| Message ID | 20240104130129.17823-4-Harald.Mommer@opensynergy.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Virtio SPI Linux driver compliant to draft spec V10 | expand |
Hi Harald, On 04-01-24, 14:01, Harald Mommer wrote: > From: Harald Mommer <harald.mommer@opensynergy.com> > > This is the virtio SPI Linux kernel driver compliant to the "PATCH v10" > draft virtio SPI specification. Its okay with the RFC, but later on, please remove the versioning part from the commit log. All such information can be added to the cover letter. > Signed-off-by: Harald Mommer <Harald.Mommer@opensynergy.com> > --- > drivers/spi/Kconfig | 11 + > drivers/spi/Makefile | 1 + > drivers/spi/spi-virtio.c | 430 +++++++++++++++++++++++++++++++++++++++ > 3 files changed, 442 insertions(+) > create mode 100644 drivers/spi/spi-virtio.c > > diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig > index ddae0fde798e..f4f617c79ad7 100644 > --- a/drivers/spi/Kconfig > +++ b/drivers/spi/Kconfig > @@ -1125,6 +1125,17 @@ config SPI_UNIPHIER > > If your SoC supports SCSSI, say Y here. > > +config SPI_VIRTIO > + tristate "Virtio SPI SPI Controller" s/SPI SPI/SPI/ ? > + depends on VIRTIO Maybe a "depends on SPI_MASTER" as well ? Or "select" ? > + help > + This enables the Virtio SPI driver. > + > + Virtio SPI is an SPI driver for virtual machines using Virtio. > + > + If your Linux is a virtual machine using Virtio, say Y here. > + If unsure, say N. > + > config SPI_XCOMM > tristate "Analog Devices AD-FMCOMMS1-EBZ SPI-I2C-bridge driver" > depends on I2C > diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile > index 4ff8d725ba5e..ff2243e44e00 100644 > --- a/drivers/spi/Makefile > +++ b/drivers/spi/Makefile > @@ -146,6 +146,7 @@ spi-thunderx-objs := spi-cavium.o spi-cavium-thunderx.o > obj-$(CONFIG_SPI_THUNDERX) += spi-thunderx.o > obj-$(CONFIG_SPI_TOPCLIFF_PCH) += spi-topcliff-pch.o > obj-$(CONFIG_SPI_UNIPHIER) += spi-uniphier.o > +obj-$(CONFIG_SPI_VIRTIO) += spi-virtio.o > obj-$(CONFIG_SPI_XCOMM) += spi-xcomm.o > obj-$(CONFIG_SPI_XILINX) += spi-xilinx.o > obj-$(CONFIG_SPI_XLP) += spi-xlp.o > diff --git a/drivers/spi/spi-virtio.c b/drivers/spi/spi-virtio.c > new file mode 100644 > index 000000000000..39eb38184793 > --- /dev/null > +++ b/drivers/spi/spi-virtio.c > @@ -0,0 +1,430 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * SPI bus driver for the Virtio SPI controller > + * Copyright (C) 2023 OpenSynergy GmbH > + */ > + > +#include <linux/completion.h> > +#include <linux/interrupt.h> > +#include <linux/io.h> > +#include <linux/kernel.h> > +#include <linux/module.h> > +#include <linux/stddef.h> > +#include <linux/virtio.h> > +#include <linux/virtio_ring.h> > +#include <linux/version.h> > +#include <linux/of.h> > +#include <linux/spi/spi.h> > +#include <linux/virtio_spi.h> Alphabetical order is preferred normally for headers. > + > +/* virtio_spi private data structure */ > +struct virtio_spi_priv { > + /* The virtio device we're associated with */ > + struct virtio_device *vdev; > + /* Pointer to the virtqueue */ > + struct virtqueue *vq; > + /* Copy of config space mode_func_supported */ > + u32 mode_func_supported; > + /* Copy of config space max_freq_hz */ > + u32 max_freq_hz; > +}; > + > +struct virtio_spi_req { > + struct completion completion; > + struct spi_transfer_head transfer_head ____cacheline_aligned; > + const uint8_t *tx_buf ____cacheline_aligned; > + uint8_t *rx_buf ____cacheline_aligned; > + struct spi_transfer_result result ____cacheline_aligned; > +}; > + > +static struct spi_board_info board_info = { > + .modalias = "spi-virtio", > +}; > + > +static void virtio_spi_msg_done(struct virtqueue *vq) > +{ > + struct virtio_spi_req *req; > + unsigned int len; > + > + while ((req = virtqueue_get_buf(vq, &len))) Do we really need a while loop here ? Since for now we are transferring the messages one by one. > + complete(&req->completion); > +} > + > +static int virtio_spi_one_transfer(struct virtio_spi_req *spi_req, > + struct spi_controller *ctrl, > + struct spi_message *msg, > + struct spi_transfer *xfer) > +{ > + struct virtio_spi_priv *priv = spi_controller_get_devdata(ctrl); > + struct device *dev = &priv->vdev->dev; > + struct spi_device *spi = msg->spi; > + struct spi_transfer_head *th; > + struct scatterlist sg_out_head, sg_out_payload; > + struct scatterlist sg_in_result, sg_in_payload; > + struct scatterlist *sgs[4]; > + unsigned int outcnt = 0u; > + unsigned int incnt = 0u; > + int ret; > + > + th = &spi_req->transfer_head; > + > + /* Fill struct spi_transfer_head */ > + th->chip_select_id = spi_get_chipselect(spi, 0); > + th->bits_per_word = spi->bits_per_word; > + /* > + * Got comment: "The virtio spec for cs_change is *not* what the Linux > + * cs_change field does, this will not do the right thing." > + * TODO: Understand/discuss this, still unclear what may be wrong here > + */ > + th->cs_change = xfer->cs_change; > + th->tx_nbits = xfer->tx_nbits; > + th->rx_nbits = xfer->rx_nbits; > + th->reserved[0] = 0; > + th->reserved[1] = 0; > + th->reserved[2] = 0; > + > + BUILD_BUG_ON(VIRTIO_SPI_CPHA != SPI_CPHA); > + BUILD_BUG_ON(VIRTIO_SPI_CPOL != SPI_CPOL); > + BUILD_BUG_ON(VIRTIO_SPI_CS_HIGH != SPI_CS_HIGH); > + BUILD_BUG_ON(VIRTIO_SPI_MODE_LSB_FIRST != SPI_LSB_FIRST); > + > + th->mode = cpu_to_le32(spi->mode & (SPI_LSB_FIRST | SPI_CS_HIGH | > + SPI_CPOL | SPI_CPHA)); > + if ((spi->mode & SPI_LOOP) != 0) > + th->mode |= cpu_to_le32(VIRTIO_SPI_MODE_LOOP); > + > + th->freq = cpu_to_le32(xfer->speed_hz); > + > + ret = spi_delay_to_ns(&xfer->word_delay, xfer); > + if (ret < 0) { > + dev_warn(dev, "Cannot convert word_delay\n"); > + goto msg_done; > + } > + th->word_delay_ns = cpu_to_le32((u32)ret); > + > + ret = spi_delay_to_ns(&xfer->delay, xfer); > + if (ret < 0) { > + dev_warn(dev, "Cannot convert delay\n"); > + goto msg_done; > + } > + th->cs_setup_ns = cpu_to_le32((u32)ret); > + th->cs_delay_hold_ns = cpu_to_le32((u32)ret); > + > + /* This is the "off" time when CS has to be deasserted for a moment */ > + ret = spi_delay_to_ns(&xfer->cs_change_delay, xfer); > + if (ret < 0) { > + dev_warn(dev, "Cannot convert cs_change_delay\n"); > + goto msg_done; > + } > + th->cs_change_delay_inactive_ns = cpu_to_le32((u32)ret); > + > + /* Set buffers */ > + spi_req->tx_buf = xfer->tx_buf; > + spi_req->rx_buf = xfer->rx_buf; > + > + /* Prepare sending of virtio message */ > + init_completion(&spi_req->completion); > + > + sg_init_one(&sg_out_head, &spi_req->transfer_head, > + sizeof(struct spi_transfer_head)); sizeof(*th) ? > + sgs[outcnt] = &sg_out_head; > + outcnt++; > + > + if (spi_req->tx_buf) { > + sg_init_one(&sg_out_payload, spi_req->tx_buf, xfer->len); > + sgs[outcnt] = &sg_out_payload; > + outcnt++; > + } > + > + if (spi_req->rx_buf) { > + sg_init_one(&sg_in_payload, spi_req->rx_buf, xfer->len); > + sgs[outcnt + incnt] = &sg_in_payload; > + incnt++; > + } > + > + sg_init_one(&sg_in_result, &spi_req->result, > + sizeof(struct spi_transfer_result)); > + sgs[outcnt + incnt] = &sg_in_result; > + incnt++; > + > + ret = virtqueue_add_sgs(priv->vq, sgs, outcnt, incnt, spi_req, > + GFP_KERNEL); > + > +msg_done: > + if (ret) > + msg->status = ret; > + > + return ret; > +} > + > +static int virtio_spi_transfer_one_message(struct spi_controller *ctrl, > + struct spi_message *msg) > +{ > + struct virtio_spi_priv *priv = spi_controller_get_devdata(ctrl); > + struct virtio_spi_req *spi_req; > + struct spi_transfer *xfer; > + int ret = 0; > + > + spi_req = kzalloc(sizeof(*spi_req), GFP_KERNEL); > + if (!spi_req) { > + ret = -ENOMEM; > + goto no_mem; > + } > + > + /* > + * Simple implementation: Process message by message and wait for each > + * message to be completed by the device side. > + */ > + list_for_each_entry(xfer, &msg->transfers, transfer_list) { > + ret = virtio_spi_one_transfer(spi_req, ctrl, msg, xfer); > + if (ret) > + goto msg_done; > + > + virtqueue_kick(priv->vq); > + > + wait_for_completion(&spi_req->completion); > + > + /* Read result from message */ > + ret = (int)spi_req->result.result; > + if (ret) > + goto msg_done; > + } > + > +msg_done: > + kfree(spi_req); > +no_mem: > + msg->status = ret; > + spi_finalize_current_message(ctrl); > + > + return ret; > +} > + > +static void virtio_spi_read_config(struct virtio_device *vdev) > +{ > + struct spi_controller *ctrl = dev_get_drvdata(&vdev->dev); > + struct virtio_spi_priv *priv = vdev->priv; > + u8 cs_max_number; > + u8 tx_nbits_supported; > + u8 rx_nbits_supported; > + > + cs_max_number = virtio_cread8(vdev, offsetof(struct virtio_spi_config, > + cs_max_number)); > + ctrl->num_chipselect = cs_max_number; > + > + /* Set the mode bits which are understood by this driver */ > + priv->mode_func_supported = > + virtio_cread32(vdev, offsetof(struct virtio_spi_config, > + mode_func_supported)); > + ctrl->mode_bits = priv->mode_func_supported & > + (VIRTIO_SPI_CS_HIGH | VIRTIO_SPI_MODE_LSB_FIRST); > + if ((priv->mode_func_supported & VIRTIO_SPI_MF_SUPPORT_CPHA_1) != 0) > + ctrl->mode_bits |= VIRTIO_SPI_CPHA; > + if ((priv->mode_func_supported & VIRTIO_SPI_MF_SUPPORT_CPOL_1) != 0) > + ctrl->mode_bits |= VIRTIO_SPI_CPOL; > + if ((priv->mode_func_supported & VIRTIO_SPI_MF_SUPPORT_LSB_FIRST) != 0) > + ctrl->mode_bits |= SPI_LSB_FIRST; > + if ((priv->mode_func_supported & VIRTIO_SPI_MF_SUPPORT_LOOPBACK) != 0) > + ctrl->mode_bits |= SPI_LOOP; > + tx_nbits_supported = > + virtio_cread8(vdev, offsetof(struct virtio_spi_config, > + tx_nbits_supported)); > + if ((tx_nbits_supported & VIRTIO_SPI_RX_TX_SUPPORT_DUAL) != 0) > + ctrl->mode_bits |= SPI_TX_DUAL; > + if ((tx_nbits_supported & VIRTIO_SPI_RX_TX_SUPPORT_QUAD) != 0) > + ctrl->mode_bits |= SPI_TX_QUAD; > + if ((tx_nbits_supported & VIRTIO_SPI_RX_TX_SUPPORT_OCTAL) != 0) > + ctrl->mode_bits |= SPI_TX_OCTAL; > + rx_nbits_supported = > + virtio_cread8(vdev, offsetof(struct virtio_spi_config, > + rx_nbits_supported)); > + if ((rx_nbits_supported & VIRTIO_SPI_RX_TX_SUPPORT_DUAL) != 0) > + ctrl->mode_bits |= SPI_RX_DUAL; > + if ((rx_nbits_supported & VIRTIO_SPI_RX_TX_SUPPORT_QUAD) != 0) > + ctrl->mode_bits |= SPI_RX_QUAD; > + if ((rx_nbits_supported & VIRTIO_SPI_RX_TX_SUPPORT_OCTAL) != 0) > + ctrl->mode_bits |= SPI_RX_OCTAL; > + > + ctrl->bits_per_word_mask = > + virtio_cread32(vdev, offsetof(struct virtio_spi_config, > + bits_per_word_mask)); > + > + priv->max_freq_hz = > + virtio_cread32(vdev, offsetof(struct virtio_spi_config, > + max_freq_hz)); > +} > + > +static int virtio_spi_find_vqs(struct virtio_spi_priv *priv) > +{ > + struct virtqueue *vq; > + > + vq = virtio_find_single_vq(priv->vdev, virtio_spi_msg_done, "spi-rq"); > + if (IS_ERR(vq)) > + return (int)PTR_ERR(vq); > + priv->vq = vq; > + return 0; > +} > + > +/* Function must not be called before virtio_spi_find_vqs() has been run */ > +static void virtio_spi_del_vq(struct virtio_device *vdev) > +{ > + virtio_reset_device(vdev); > + vdev->config->del_vqs(vdev); > +} > + > +static int virtio_spi_validate(struct virtio_device *vdev) > +{ > + /* > + * SPI needs always access to the config space. > + * Check that the driver can access the config space > + */ > + if (!vdev->config->get) { > + dev_err(&vdev->dev, "%s failure: config access disabled\n", > + __func__); > + return -EINVAL; > + } > + > + if (!virtio_has_feature(vdev, VIRTIO_F_VERSION_1)) { > + dev_err(&vdev->dev, > + "device does not comply with spec version 1.x\n"); > + return -EINVAL; > + } > + > + return 0; > +} > + > +static int virtio_spi_probe(struct virtio_device *vdev) > +{ > + struct device_node *np = vdev->dev.parent->of_node; > + struct virtio_spi_priv *priv; > + struct spi_controller *ctrl; > + int err; > + u32 bus_num; > + u16 csi; > + > + ctrl = devm_spi_alloc_host(&vdev->dev, sizeof(*priv)); > + if (!ctrl) { > + dev_err(&vdev->dev, "Kernel memory exhausted in %s()\n", > + __func__); I thought you agreed to drop it earlier ? > + err = -ENOMEM; > + goto err_return; > + } > + > + priv = spi_controller_get_devdata(ctrl); > + priv->vdev = vdev; > + vdev->priv = priv; > + dev_set_drvdata(&vdev->dev, ctrl); > + > + err = of_property_read_u32(np, "spi,bus-num", &bus_num); > + if (!err && bus_num <= S16_MAX) > + ctrl->bus_num = (s16)bus_num; > + > + virtio_spi_read_config(vdev); > + > + /* Method to transfer a single SPI message */ > + ctrl->transfer_one_message = virtio_spi_transfer_one_message; > + > + /* Initialize virtqueues */ > + err = virtio_spi_find_vqs(priv); > + if (err) { > + dev_err(&vdev->dev, "Cannot setup virtqueues\n"); > + goto err_return; > + } > + > + err = spi_register_controller(ctrl); > + if (err) { Remove virtqueues here ? > + dev_err(&vdev->dev, "Cannot register controller\n"); > + goto err_return; > + } > + > + board_info.max_speed_hz = priv->max_freq_hz; > + /* spi_new_device() currently does not use bus_num but better set it */ > + board_info.bus_num = (u16)ctrl->bus_num; > + > + /* Add chip selects to controller */ > + for (csi = 0; csi < ctrl->num_chipselect; csi++) { > + dev_dbg(&vdev->dev, "Setting up CS=%u\n", csi); > + board_info.chip_select = csi; > + /* TODO: Discuss setting of board_info.mode */ > + if (!(priv->mode_func_supported & VIRTIO_SPI_CS_HIGH)) > + board_info.mode = SPI_MODE_0; > + else > + board_info.mode = SPI_MODE_0 | SPI_CS_HIGH; > + if (!spi_new_device(ctrl, &board_info)) { > + dev_err(&vdev->dev, "Cannot setup device %u\n", csi); > + err = -ENODEV; Remove controller and virtqueues here ? > + goto err_return; > + } > + } > + > + return 0; > + > +err_return: > + return err; > +}
On 1/4/2024 9:01 PM, Harald Mommer wrote: > +static int virtio_spi_one_transfer(struct virtio_spi_req *spi_req, > + struct spi_controller *ctrl, > + struct spi_message *msg, > + struct spi_transfer *xfer) > +{ > + struct virtio_spi_priv *priv = spi_controller_get_devdata(ctrl); > + struct device *dev = &priv->vdev->dev; > + struct spi_device *spi = msg->spi; > + struct spi_transfer_head *th; > + struct scatterlist sg_out_head, sg_out_payload; > + struct scatterlist sg_in_result, sg_in_payload; > + struct scatterlist *sgs[4]; > + unsigned int outcnt = 0u; > + unsigned int incnt = 0u; > + int ret; > + > + th = &spi_req->transfer_head; > + > + /* Fill struct spi_transfer_head */ > + th->chip_select_id = spi_get_chipselect(spi, 0); > + th->bits_per_word = spi->bits_per_word; > + /* > + * Got comment: "The virtio spec for cs_change is*not* what the Linux > + * cs_change field does, this will not do the right thing." > + * TODO: Understand/discuss this, still unclear what may be wrong here > + */ > + th->cs_change = xfer->cs_change; > + th->tx_nbits = xfer->tx_nbits; > + th->rx_nbits = xfer->rx_nbits; > + th->reserved[0] = 0; > + th->reserved[1] = 0; > + th->reserved[2] = 0; > + > + BUILD_BUG_ON(VIRTIO_SPI_CPHA != SPI_CPHA); > + BUILD_BUG_ON(VIRTIO_SPI_CPOL != SPI_CPOL); > + BUILD_BUG_ON(VIRTIO_SPI_CS_HIGH != SPI_CS_HIGH); > + BUILD_BUG_ON(VIRTIO_SPI_MODE_LSB_FIRST != SPI_LSB_FIRST); > + > + th->mode = cpu_to_le32(spi->mode & (SPI_LSB_FIRST | SPI_CS_HIGH | > + SPI_CPOL | SPI_CPHA)); > + if ((spi->mode & SPI_LOOP) != 0) > + th->mode |= cpu_to_le32(VIRTIO_SPI_MODE_LOOP); > + > + th->freq = cpu_to_le32(xfer->speed_hz); > + > + ret = spi_delay_to_ns(&xfer->word_delay, xfer); > + if (ret < 0) { > + dev_warn(dev, "Cannot convert word_delay\n"); > + goto msg_done; > + } > + th->word_delay_ns = cpu_to_le32((u32)ret); > + > + ret = spi_delay_to_ns(&xfer->delay, xfer); > + if (ret < 0) { > + dev_warn(dev, "Cannot convert delay\n"); > + goto msg_done; > + } > + th->cs_setup_ns = cpu_to_le32((u32)ret); > + th->cs_delay_hold_ns = cpu_to_le32((u32)ret); > + > + /* This is the "off" time when CS has to be deasserted for a moment */ > + ret = spi_delay_to_ns(&xfer->cs_change_delay, xfer); > + if (ret < 0) { > + dev_warn(dev, "Cannot convert cs_change_delay\n"); > + goto msg_done; > + } > + th->cs_change_delay_inactive_ns = cpu_to_le32((u32)ret); Hi Harald, spi_device structure has three cs timing members, which will also affect the cs timing. struct spi_device { ... struct spi_delay cs_setup; struct spi_delay cs_hold; struct spi_delay cs_inactive; ... } These three values should also be passed to the backend, for the controller to control cs lines. spi_device->cs_setup is the delay before cs asserted, spi_device->cs_hold with spi_transfer->delay work before cs deasserted, and spi_device->cs_inactive with spi_transfer->cs_change_delay take effect at the stage after cs deasserted. Here is the diagram . . . . . . . . . . Delay + A + + B + + C + D + E + F + A + . . . . . . . . . . ___. . . . . . .___.___. . CS# |___.______.____.____.___.___| . |___._____________ . . . . . . . . . . . . . . . . . . . . SCLK__.___.___NNN_____NNN__.___.___.___.___.___.___NNN_______ NOTE: 1st transfer has two words, the delay betweent these two words are 'B' in the diagram. A => struct spi_device -> cs_setup B => max{struct spi_transfer -> word_delay, struct spi_device -> word_delay} Note: spi_device and spi_transfer both have word_delay, Linux choose the bigger one, refer to _spi_xfer_word_delay_update function C => struct spi_transfer -> delay D => struct spi_device -> cs_hold E => struct spi_device -> cs_inactive F => struct spi_transfer -> cs_change_delay So the corresponding relationship: A <===> cs_setup_ns (after CS asserted) B <===> word_delay_ns (no matter with CS) C+D <===> cs_delay_hold_ns (before CS deasserted) E+F <===> cs_change_delay_inactive_ns (after CS deasserted, these two values also recommend in Linux driver to be added up) Best Regards Haixu > + > + /* Set buffers */ > + spi_req->tx_buf = xfer->tx_buf; > + spi_req->rx_buf = xfer->rx_buf; > + > + /* Prepare sending of virtio message */ > + init_completion(&spi_req->completion); > + > + sg_init_one(&sg_out_head, &spi_req->transfer_head, > + sizeof(struct spi_transfer_head)); > + sgs[outcnt] = &sg_out_head; > + outcnt++; > + > + if (spi_req->tx_buf) { > + sg_init_one(&sg_out_payload, spi_req->tx_buf, xfer->len); > + sgs[outcnt] = &sg_out_payload; > + outcnt++; > + } > + > + if (spi_req->rx_buf) { > + sg_init_one(&sg_in_payload, spi_req->rx_buf, xfer->len); > + sgs[outcnt + incnt] = &sg_in_payload; > + incnt++; > + } > + > + sg_init_one(&sg_in_result, &spi_req->result, > + sizeof(struct spi_transfer_result)); > + sgs[outcnt + incnt] = &sg_in_result; > + incnt++; > + > + ret = virtqueue_add_sgs(priv->vq, sgs, outcnt, incnt, spi_req, > + GFP_KERNEL); > + > +msg_done: > + if (ret) > + msg->status = ret; > + > + return ret; > +}
Hello, On 29.01.24 08:06, Viresh Kumar wrote: > Hi Harald, > > On 04-01-24, 14:01, Harald Mommer wrote: >> From: Harald Mommer<harald.mommer@opensynergy.com> >> >> This is the virtio SPI Linux kernel driver compliant to the "PATCH v10" >> draft virtio SPI specification. > Its okay with the RFC, but later on, please remove the versioning part > from the commit log. All such information can be added to the cover > letter. For the future. This driver needs to remain RFC at least until the SPI specification is accepted anyway. >> Signed-off-by: Harald Mommer<Harald.Mommer@opensynergy.com> >> --- >> drivers/spi/Kconfig | 11 + >> drivers/spi/Makefile | 1 + >> drivers/spi/spi-virtio.c | 430 +++++++++++++++++++++++++++++++++++++++ >> 3 files changed, 442 insertions(+) >> create mode 100644 drivers/spi/spi-virtio.c >> >> diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig >> index ddae0fde798e..f4f617c79ad7 100644 >> --- a/drivers/spi/Kconfig >> +++ b/drivers/spi/Kconfig >> @@ -1125,6 +1125,17 @@ config SPI_UNIPHIER >> >> If your SoC supports SCSSI, say Y here. >> >> +config SPI_VIRTIO >> + tristate "Virtio SPI SPI Controller" > s/SPI SPI/SPI/ ? Will fix. >> + depends on VIRTIO > Maybe a "depends on SPI_MASTER" as well ? Or "select" ? This depends clearly on SPI_MASTER so something has to happen here. >> + help >> + This enables the Virtio SPI driver. >> + >> + Virtio SPI is an SPI driver for virtual machines using Virtio. >> + >> + If your Linux is a virtual machine using Virtio, say Y here. >> + If unsure, say N. >> + >> config SPI_XCOMM >> tristate "Analog Devices AD-FMCOMMS1-EBZ SPI-I2C-bridge driver" >> depends on I2C >> diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile >> index 4ff8d725ba5e..ff2243e44e00 100644 >> --- a/drivers/spi/Makefile >> +++ b/drivers/spi/Makefile >> @@ -146,6 +146,7 @@ spi-thunderx-objs := spi-cavium.o spi-cavium-thunderx.o >> obj-$(CONFIG_SPI_THUNDERX) += spi-thunderx.o >> obj-$(CONFIG_SPI_TOPCLIFF_PCH) += spi-topcliff-pch.o >> obj-$(CONFIG_SPI_UNIPHIER) += spi-uniphier.o >> +obj-$(CONFIG_SPI_VIRTIO) += spi-virtio.o >> obj-$(CONFIG_SPI_XCOMM) += spi-xcomm.o >> obj-$(CONFIG_SPI_XILINX) += spi-xilinx.o >> obj-$(CONFIG_SPI_XLP) += spi-xlp.o >> diff --git a/drivers/spi/spi-virtio.c b/drivers/spi/spi-virtio.c >> new file mode 100644 >> index 000000000000..39eb38184793 >> --- /dev/null >> +++ b/drivers/spi/spi-virtio.c >> @@ -0,0 +1,430 @@ >> +// SPDX-License-Identifier: GPL-2.0-only >> +/* >> + * SPI bus driver for the Virtio SPI controller >> + * Copyright (C) 2023 OpenSynergy GmbH >> + */ >> + >> +#include <linux/completion.h> >> +#include <linux/interrupt.h> >> +#include <linux/io.h> >> +#include <linux/kernel.h> >> +#include <linux/module.h> >> +#include <linux/stddef.h> >> +#include <linux/virtio.h> >> +#include <linux/virtio_ring.h> >> +#include <linux/version.h> >> +#include <linux/of.h> >> +#include <linux/spi/spi.h> >> +#include <linux/virtio_spi.h> > Alphabetical order is preferred normally for headers. Did not know, can do. As long as the compiler does not overrule me, of course. >> + >> +/* virtio_spi private data structure */ >> +struct virtio_spi_priv { >> + /* The virtio device we're associated with */ >> + struct virtio_device *vdev; >> + /* Pointer to the virtqueue */ >> + struct virtqueue *vq; >> + /* Copy of config space mode_func_supported */ >> + u32 mode_func_supported; >> + /* Copy of config space max_freq_hz */ >> + u32 max_freq_hz; >> +}; >> + >> +struct virtio_spi_req { >> + struct completion completion; >> + struct spi_transfer_head transfer_head ____cacheline_aligned; >> + const uint8_t *tx_buf ____cacheline_aligned; >> + uint8_t *rx_buf ____cacheline_aligned; >> + struct spi_transfer_result result ____cacheline_aligned; >> +}; >> + >> +static struct spi_board_info board_info = { >> + .modalias = "spi-virtio", >> +}; >> + >> +static void virtio_spi_msg_done(struct virtqueue *vq) >> +{ >> + struct virtio_spi_req *req; >> + unsigned int len; >> + >> + while ((req = virtqueue_get_buf(vq, &len))) > Do we really need a while loop here ? Since for now we are > transferring the messages one by one. Not strictly needed here yet as there is still this restriction transmitting messages. But we all know that this will not remain that way for too long, there is also no bug here so I prefer to keep it as it was done in virtio_i2c_msg_done(). >> + complete(&req->completion); >> +} >> + >> +static int virtio_spi_one_transfer(struct virtio_spi_req *spi_req, >> + struct spi_controller *ctrl, >> + struct spi_message *msg, >> + struct spi_transfer *xfer) >> +{ >> + struct virtio_spi_priv *priv = spi_controller_get_devdata(ctrl); >> + struct device *dev = &priv->vdev->dev; >> + struct spi_device *spi = msg->spi; >> + struct spi_transfer_head *th; >> + struct scatterlist sg_out_head, sg_out_payload; >> + struct scatterlist sg_in_result, sg_in_payload; >> + struct scatterlist *sgs[4]; >> + unsigned int outcnt = 0u; >> + unsigned int incnt = 0u; >> + int ret; >> + >> + th = &spi_req->transfer_head; >> + >> + /* Fill struct spi_transfer_head */ >> + th->chip_select_id = spi_get_chipselect(spi, 0); >> + th->bits_per_word = spi->bits_per_word; >> + /* >> + * Got comment: "The virtio spec for cs_change is *not* what the Linux >> + * cs_change field does, this will not do the right thing." >> + * TODO: Understand/discuss this, still unclear what may be wrong here >> + */ >> + th->cs_change = xfer->cs_change; >> + th->tx_nbits = xfer->tx_nbits; >> + th->rx_nbits = xfer->rx_nbits; >> + th->reserved[0] = 0; >> + th->reserved[1] = 0; >> + th->reserved[2] = 0; >> + >> + BUILD_BUG_ON(VIRTIO_SPI_CPHA != SPI_CPHA); >> + BUILD_BUG_ON(VIRTIO_SPI_CPOL != SPI_CPOL); >> + BUILD_BUG_ON(VIRTIO_SPI_CS_HIGH != SPI_CS_HIGH); >> + BUILD_BUG_ON(VIRTIO_SPI_MODE_LSB_FIRST != SPI_LSB_FIRST); >> + >> + th->mode = cpu_to_le32(spi->mode & (SPI_LSB_FIRST | SPI_CS_HIGH | >> + SPI_CPOL | SPI_CPHA)); >> + if ((spi->mode & SPI_LOOP) != 0) >> + th->mode |= cpu_to_le32(VIRTIO_SPI_MODE_LOOP); >> + >> + th->freq = cpu_to_le32(xfer->speed_hz); >> + >> + ret = spi_delay_to_ns(&xfer->word_delay, xfer); >> + if (ret < 0) { >> + dev_warn(dev, "Cannot convert word_delay\n"); >> + goto msg_done; >> + } >> + th->word_delay_ns = cpu_to_le32((u32)ret); >> + >> + ret = spi_delay_to_ns(&xfer->delay, xfer); >> + if (ret < 0) { >> + dev_warn(dev, "Cannot convert delay\n"); >> + goto msg_done; >> + } >> + th->cs_setup_ns = cpu_to_le32((u32)ret); >> + th->cs_delay_hold_ns = cpu_to_le32((u32)ret); >> + >> + /* This is the "off" time when CS has to be deasserted for a moment */ >> + ret = spi_delay_to_ns(&xfer->cs_change_delay, xfer); >> + if (ret < 0) { >> + dev_warn(dev, "Cannot convert cs_change_delay\n"); >> + goto msg_done; >> + } >> + th->cs_change_delay_inactive_ns = cpu_to_le32((u32)ret); >> + >> + /* Set buffers */ >> + spi_req->tx_buf = xfer->tx_buf; >> + spi_req->rx_buf = xfer->rx_buf; >> + >> + /* Prepare sending of virtio message */ >> + init_completion(&spi_req->completion); >> + >> + sg_init_one(&sg_out_head, &spi_req->transfer_head, >> + sizeof(struct spi_transfer_head)); > sizeof(*th) ? Yes. But then in the form sg_init_one(&sg_out_head, th, sizeof(*th)); >> + sgs[outcnt] = &sg_out_head; >> + outcnt++; >> + >> + if (spi_req->tx_buf) { >> + sg_init_one(&sg_out_payload, spi_req->tx_buf, xfer->len); >> + sgs[outcnt] = &sg_out_payload; >> + outcnt++; >> + } >> + >> + if (spi_req->rx_buf) { >> + sg_init_one(&sg_in_payload, spi_req->rx_buf, xfer->len); >> + sgs[outcnt + incnt] = &sg_in_payload; >> + incnt++; >> + } >> + >> + sg_init_one(&sg_in_result, &spi_req->result, >> + sizeof(struct spi_transfer_result)); >> + sgs[outcnt + incnt] = &sg_in_result; >> + incnt++; >> + >> + ret = virtqueue_add_sgs(priv->vq, sgs, outcnt, incnt, spi_req, >> + GFP_KERNEL); >> + >> +msg_done: >> + if (ret) >> + msg->status = ret; >> + >> + return ret; >> +} >> + >> +static int virtio_spi_transfer_one_message(struct spi_controller *ctrl, >> + struct spi_message *msg) >> +{ >> + struct virtio_spi_priv *priv = spi_controller_get_devdata(ctrl); >> + struct virtio_spi_req *spi_req; >> + struct spi_transfer *xfer; >> + int ret = 0; >> + >> + spi_req = kzalloc(sizeof(*spi_req), GFP_KERNEL); >> + if (!spi_req) { >> + ret = -ENOMEM; >> + goto no_mem; >> + } >> + >> + /* >> + * Simple implementation: Process message by message and wait for each >> + * message to be completed by the device side. >> + */ >> + list_for_each_entry(xfer, &msg->transfers, transfer_list) { >> + ret = virtio_spi_one_transfer(spi_req, ctrl, msg, xfer); >> + if (ret) >> + goto msg_done; >> + >> + virtqueue_kick(priv->vq); >> + >> + wait_for_completion(&spi_req->completion); >> + >> + /* Read result from message */ >> + ret = (int)spi_req->result.result; >> + if (ret) >> + goto msg_done; >> + } >> + >> +msg_done: >> + kfree(spi_req); >> +no_mem: >> + msg->status = ret; >> + spi_finalize_current_message(ctrl); >> + >> + return ret; >> +} >> + >> +static void virtio_spi_read_config(struct virtio_device *vdev) >> +{ >> + struct spi_controller *ctrl = dev_get_drvdata(&vdev->dev); >> + struct virtio_spi_priv *priv = vdev->priv; >> + u8 cs_max_number; >> + u8 tx_nbits_supported; >> + u8 rx_nbits_supported; >> + >> + cs_max_number = virtio_cread8(vdev, offsetof(struct virtio_spi_config, >> + cs_max_number)); >> + ctrl->num_chipselect = cs_max_number; >> + >> + /* Set the mode bits which are understood by this driver */ >> + priv->mode_func_supported = >> + virtio_cread32(vdev, offsetof(struct virtio_spi_config, >> + mode_func_supported)); >> + ctrl->mode_bits = priv->mode_func_supported & >> + (VIRTIO_SPI_CS_HIGH | VIRTIO_SPI_MODE_LSB_FIRST); >> + if ((priv->mode_func_supported & VIRTIO_SPI_MF_SUPPORT_CPHA_1) != 0) >> + ctrl->mode_bits |= VIRTIO_SPI_CPHA; >> + if ((priv->mode_func_supported & VIRTIO_SPI_MF_SUPPORT_CPOL_1) != 0) >> + ctrl->mode_bits |= VIRTIO_SPI_CPOL; >> + if ((priv->mode_func_supported & VIRTIO_SPI_MF_SUPPORT_LSB_FIRST) != 0) >> + ctrl->mode_bits |= SPI_LSB_FIRST; >> + if ((priv->mode_func_supported & VIRTIO_SPI_MF_SUPPORT_LOOPBACK) != 0) >> + ctrl->mode_bits |= SPI_LOOP; >> + tx_nbits_supported = >> + virtio_cread8(vdev, offsetof(struct virtio_spi_config, >> + tx_nbits_supported)); >> + if ((tx_nbits_supported & VIRTIO_SPI_RX_TX_SUPPORT_DUAL) != 0) >> + ctrl->mode_bits |= SPI_TX_DUAL; >> + if ((tx_nbits_supported & VIRTIO_SPI_RX_TX_SUPPORT_QUAD) != 0) >> + ctrl->mode_bits |= SPI_TX_QUAD; >> + if ((tx_nbits_supported & VIRTIO_SPI_RX_TX_SUPPORT_OCTAL) != 0) >> + ctrl->mode_bits |= SPI_TX_OCTAL; >> + rx_nbits_supported = >> + virtio_cread8(vdev, offsetof(struct virtio_spi_config, >> + rx_nbits_supported)); >> + if ((rx_nbits_supported & VIRTIO_SPI_RX_TX_SUPPORT_DUAL) != 0) >> + ctrl->mode_bits |= SPI_RX_DUAL; >> + if ((rx_nbits_supported & VIRTIO_SPI_RX_TX_SUPPORT_QUAD) != 0) >> + ctrl->mode_bits |= SPI_RX_QUAD; >> + if ((rx_nbits_supported & VIRTIO_SPI_RX_TX_SUPPORT_OCTAL) != 0) >> + ctrl->mode_bits |= SPI_RX_OCTAL; >> + >> + ctrl->bits_per_word_mask = >> + virtio_cread32(vdev, offsetof(struct virtio_spi_config, >> + bits_per_word_mask)); >> + >> + priv->max_freq_hz = >> + virtio_cread32(vdev, offsetof(struct virtio_spi_config, >> + max_freq_hz)); >> +} >> + >> +static int virtio_spi_find_vqs(struct virtio_spi_priv *priv) >> +{ >> + struct virtqueue *vq; >> + >> + vq = virtio_find_single_vq(priv->vdev, virtio_spi_msg_done, "spi-rq"); >> + if (IS_ERR(vq)) >> + return (int)PTR_ERR(vq); >> + priv->vq = vq; >> + return 0; >> +} >> + >> +/* Function must not be called before virtio_spi_find_vqs() has been run */ >> +static void virtio_spi_del_vq(struct virtio_device *vdev) >> +{ >> + virtio_reset_device(vdev); >> + vdev->config->del_vqs(vdev); >> +} >> + >> +static int virtio_spi_validate(struct virtio_device *vdev) >> +{ >> + /* >> + * SPI needs always access to the config space. >> + * Check that the driver can access the config space >> + */ >> + if (!vdev->config->get) { >> + dev_err(&vdev->dev, "%s failure: config access disabled\n", >> + __func__); >> + return -EINVAL; >> + } >> + >> + if (!virtio_has_feature(vdev, VIRTIO_F_VERSION_1)) { >> + dev_err(&vdev->dev, >> + "device does not comply with spec version 1.x\n"); >> + return -EINVAL; >> + } >> + >> + return 0; >> +} >> + >> +static int virtio_spi_probe(struct virtio_device *vdev) >> +{ >> + struct device_node *np = vdev->dev.parent->of_node; >> + struct virtio_spi_priv *priv; >> + struct spi_controller *ctrl; >> + int err; >> + u32 bus_num; >> + u16 csi; >> + >> + ctrl = devm_spi_alloc_host(&vdev->dev, sizeof(*priv)); >> + if (!ctrl) { >> + dev_err(&vdev->dev, "Kernel memory exhausted in %s()\n", >> + __func__); > I thought you agreed to drop it earlier ? Tried to do this. But I've to maintain a driver version which is not based on latest, our internal master from which the public version is derived. So there is code which still has to free resources, you just don't see it. Was not happy when I realized that I have not yet devm_spi_alloc_host() everywhere where I need it. In this code there is #if LINUX_VERSION_CODE < KERNEL_VERSION(6, 2, 0) ctrl = spi_alloc_master(&vdev->dev, sizeof(*priv)); #else ctrl = devm_spi_alloc_host(&vdev->dev, sizeof(*priv)); #endif .... err_return: #if LINUX_VERSION_CODE < KERNEL_VERSION(6, 2, 0) spi_controller_put(ctrl); #endif return err; Either using goto minimizing the number of #if in the code or getting an unreadable #if mess in my "master" implementation which needs to be compliant also to 6.1 and even 4.14. >> + err = -ENOMEM; >> + goto err_return; >> + } >> + >> + priv = spi_controller_get_devdata(ctrl); >> + priv->vdev = vdev; >> + vdev->priv = priv; >> + dev_set_drvdata(&vdev->dev, ctrl); >> + >> + err = of_property_read_u32(np, "spi,bus-num", &bus_num); >> + if (!err && bus_num <= S16_MAX) >> + ctrl->bus_num = (s16)bus_num; >> + >> + virtio_spi_read_config(vdev); >> + >> + /* Method to transfer a single SPI message */ >> + ctrl->transfer_one_message = virtio_spi_transfer_one_message; >> + >> + /* Initialize virtqueues */ >> + err = virtio_spi_find_vqs(priv); >> + if (err) { >> + dev_err(&vdev->dev, "Cannot setup virtqueues\n"); >> + goto err_return; >> + } >> + >> + err = spi_register_controller(ctrl); >> + if (err) { > Remove virtqueues here ? Indeed missing. I guess vdev->config->del_vqs(vdev); is still my friend here.And not only here but also below, so new label "err_return_del_vq:" to do it centrally at the end of the function. And what is also to be improved here is the spi_register_controller() as I should better use devm_spi_register_controller() to get the resource de-allocation managed. Another #if in my "master" implementation but I've to live with it. >> + dev_err(&vdev->dev, "Cannot register controller\n"); >> + goto err_return; >> + } >> + >> + board_info.max_speed_hz = priv->max_freq_hz; >> + /* spi_new_device() currently does not use bus_num but better set it */ >> + board_info.bus_num = (u16)ctrl->bus_num; >> + >> + /* Add chip selects to controller */ >> + for (csi = 0; csi < ctrl->num_chipselect; csi++) { >> + dev_dbg(&vdev->dev, "Setting up CS=%u\n", csi); >> + board_info.chip_select = csi; >> + /* TODO: Discuss setting of board_info.mode */ >> + if (!(priv->mode_func_supported & VIRTIO_SPI_CS_HIGH)) >> + board_info.mode = SPI_MODE_0; >> + else >> + board_info.mode = SPI_MODE_0 | SPI_CS_HIGH; >> + if (!spi_new_device(ctrl, &board_info)) { >> + dev_err(&vdev->dev, "Cannot setup device %u\n", csi); >> + err = -ENODEV; > Remove controller and virtqueues here ? "vdev->config->del_vqs(vdev);" is missing => goto err_return_del_vq; Not sure about controller. In my internal code also for older kernels I've a #if LINUX_VERSION_CODE < KERNEL_VERSION(6, 2, 0) spi_unregister_controller(ctrl); #endif and at the end of the function a spi_controller_put(ctrl); but nothing of this here as reading the comments devm_spi_alloc_host() => __devm_spi_alloc_controller() " * Allocate an SPI controller and automatically release a reference on it * when @dev is unbound from its driver. Drivers are thus relieved from * having to call spi_controller_put()." no spi_controller_put() with devm. Using devm_spi_register_controller() instead of the bare spi_register_controller() above it should not be necessary to do anything with the controller. >> + goto err_return; >> + } >> + } >> + >> + return 0; >> + >> +err_return: >> + return err; >> +}
Hello Haixu, Thanks. This was a hard one. I knew that I did the delay settingsmost probably somewhat wrong but I had no idea that I did it so wrong. Reworked, made a new function for this, currently testing. Added the link to the place where your E-Mail is stored https://lore.kernel.org/all/6171c1c3-55ba-4f74-ae60-764820cf1caf@quicinc.com/ as a comment to the source code and hope this will survive the reviews. Another option would be to add the diagram + the explanations below as quoted here as comment to the code. Whether 30+ lines of comments would survive the reviews I don't know. Just to say nothing in the code making live hard for people trying to understand the code is something I would like to avoid. Regards Harald On 30.01.24 04:21, Haixu Cui wrote: > . . . . . . . . . . > Delay + A + + B + + C + D + E + F + A + > . . . . . . . . . . > ___. . . . . . .___.___. . > CS# |___.______.____.____.___.___| . |___._____________ > . . . . . . . . . . > . . . . . . . . . . > SCLK__.___.___NNN_____NNN__.___.___.___.___.___.___NNN_______ > > > NOTE: 1st transfer has two words, the delay betweent these two words > are 'B' in the diagram. > > A => struct spi_device -> cs_setup > B => max{struct spi_transfer -> word_delay, > struct spi_device -> word_delay} > Note: spi_device and spi_transfer both have word_delay, Linux > choose the bigger one, refer to _spi_xfer_word_delay_update > function > C => struct spi_transfer -> delay > D => struct spi_device -> cs_hold > E => struct spi_device -> cs_inactive > F => struct spi_transfer -> cs_change_delay > > So the corresponding relationship: > A <===> cs_setup_ns (after CS asserted) > B <===> word_delay_ns (no matter with CS) > C+D <===> cs_delay_hold_ns (before CS deasserted) > E+F <===> cs_change_delay_inactive_ns (after CS deasserted, these two > values also recommend in Linux driver to be added up)
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig index ddae0fde798e..f4f617c79ad7 100644 --- a/drivers/spi/Kconfig +++ b/drivers/spi/Kconfig @@ -1125,6 +1125,17 @@ config SPI_UNIPHIER If your SoC supports SCSSI, say Y here. +config SPI_VIRTIO + tristate "Virtio SPI SPI Controller" + depends on VIRTIO + help + This enables the Virtio SPI driver. + + Virtio SPI is an SPI driver for virtual machines using Virtio. + + If your Linux is a virtual machine using Virtio, say Y here. + If unsure, say N. + config SPI_XCOMM tristate "Analog Devices AD-FMCOMMS1-EBZ SPI-I2C-bridge driver" depends on I2C diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile index 4ff8d725ba5e..ff2243e44e00 100644 --- a/drivers/spi/Makefile +++ b/drivers/spi/Makefile @@ -146,6 +146,7 @@ spi-thunderx-objs := spi-cavium.o spi-cavium-thunderx.o obj-$(CONFIG_SPI_THUNDERX) += spi-thunderx.o obj-$(CONFIG_SPI_TOPCLIFF_PCH) += spi-topcliff-pch.o obj-$(CONFIG_SPI_UNIPHIER) += spi-uniphier.o +obj-$(CONFIG_SPI_VIRTIO) += spi-virtio.o obj-$(CONFIG_SPI_XCOMM) += spi-xcomm.o obj-$(CONFIG_SPI_XILINX) += spi-xilinx.o obj-$(CONFIG_SPI_XLP) += spi-xlp.o diff --git a/drivers/spi/spi-virtio.c b/drivers/spi/spi-virtio.c new file mode 100644 index 000000000000..39eb38184793 --- /dev/null +++ b/drivers/spi/spi-virtio.c @@ -0,0 +1,430 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * SPI bus driver for the Virtio SPI controller + * Copyright (C) 2023 OpenSynergy GmbH + */ + +#include <linux/completion.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/stddef.h> +#include <linux/virtio.h> +#include <linux/virtio_ring.h> +#include <linux/version.h> +#include <linux/of.h> +#include <linux/spi/spi.h> +#include <linux/virtio_spi.h> + +/* virtio_spi private data structure */ +struct virtio_spi_priv { + /* The virtio device we're associated with */ + struct virtio_device *vdev; + /* Pointer to the virtqueue */ + struct virtqueue *vq; + /* Copy of config space mode_func_supported */ + u32 mode_func_supported; + /* Copy of config space max_freq_hz */ + u32 max_freq_hz; +}; + +struct virtio_spi_req { + struct completion completion; + struct spi_transfer_head transfer_head ____cacheline_aligned; + const uint8_t *tx_buf ____cacheline_aligned; + uint8_t *rx_buf ____cacheline_aligned; + struct spi_transfer_result result ____cacheline_aligned; +}; + +static struct spi_board_info board_info = { + .modalias = "spi-virtio", +}; + +static void virtio_spi_msg_done(struct virtqueue *vq) +{ + struct virtio_spi_req *req; + unsigned int len; + + while ((req = virtqueue_get_buf(vq, &len))) + complete(&req->completion); +} + +static int virtio_spi_one_transfer(struct virtio_spi_req *spi_req, + struct spi_controller *ctrl, + struct spi_message *msg, + struct spi_transfer *xfer) +{ + struct virtio_spi_priv *priv = spi_controller_get_devdata(ctrl); + struct device *dev = &priv->vdev->dev; + struct spi_device *spi = msg->spi; + struct spi_transfer_head *th; + struct scatterlist sg_out_head, sg_out_payload; + struct scatterlist sg_in_result, sg_in_payload; + struct scatterlist *sgs[4]; + unsigned int outcnt = 0u; + unsigned int incnt = 0u; + int ret; + + th = &spi_req->transfer_head; + + /* Fill struct spi_transfer_head */ + th->chip_select_id = spi_get_chipselect(spi, 0); + th->bits_per_word = spi->bits_per_word; + /* + * Got comment: "The virtio spec for cs_change is *not* what the Linux + * cs_change field does, this will not do the right thing." + * TODO: Understand/discuss this, still unclear what may be wrong here + */ + th->cs_change = xfer->cs_change; + th->tx_nbits = xfer->tx_nbits; + th->rx_nbits = xfer->rx_nbits; + th->reserved[0] = 0; + th->reserved[1] = 0; + th->reserved[2] = 0; + + BUILD_BUG_ON(VIRTIO_SPI_CPHA != SPI_CPHA); + BUILD_BUG_ON(VIRTIO_SPI_CPOL != SPI_CPOL); + BUILD_BUG_ON(VIRTIO_SPI_CS_HIGH != SPI_CS_HIGH); + BUILD_BUG_ON(VIRTIO_SPI_MODE_LSB_FIRST != SPI_LSB_FIRST); + + th->mode = cpu_to_le32(spi->mode & (SPI_LSB_FIRST | SPI_CS_HIGH | + SPI_CPOL | SPI_CPHA)); + if ((spi->mode & SPI_LOOP) != 0) + th->mode |= cpu_to_le32(VIRTIO_SPI_MODE_LOOP); + + th->freq = cpu_to_le32(xfer->speed_hz); + + ret = spi_delay_to_ns(&xfer->word_delay, xfer); + if (ret < 0) { + dev_warn(dev, "Cannot convert word_delay\n"); + goto msg_done; + } + th->word_delay_ns = cpu_to_le32((u32)ret); + + ret = spi_delay_to_ns(&xfer->delay, xfer); + if (ret < 0) { + dev_warn(dev, "Cannot convert delay\n"); + goto msg_done; + } + th->cs_setup_ns = cpu_to_le32((u32)ret); + th->cs_delay_hold_ns = cpu_to_le32((u32)ret); + + /* This is the "off" time when CS has to be deasserted for a moment */ + ret = spi_delay_to_ns(&xfer->cs_change_delay, xfer); + if (ret < 0) { + dev_warn(dev, "Cannot convert cs_change_delay\n"); + goto msg_done; + } + th->cs_change_delay_inactive_ns = cpu_to_le32((u32)ret); + + /* Set buffers */ + spi_req->tx_buf = xfer->tx_buf; + spi_req->rx_buf = xfer->rx_buf; + + /* Prepare sending of virtio message */ + init_completion(&spi_req->completion); + + sg_init_one(&sg_out_head, &spi_req->transfer_head, + sizeof(struct spi_transfer_head)); + sgs[outcnt] = &sg_out_head; + outcnt++; + + if (spi_req->tx_buf) { + sg_init_one(&sg_out_payload, spi_req->tx_buf, xfer->len); + sgs[outcnt] = &sg_out_payload; + outcnt++; + } + + if (spi_req->rx_buf) { + sg_init_one(&sg_in_payload, spi_req->rx_buf, xfer->len); + sgs[outcnt + incnt] = &sg_in_payload; + incnt++; + } + + sg_init_one(&sg_in_result, &spi_req->result, + sizeof(struct spi_transfer_result)); + sgs[outcnt + incnt] = &sg_in_result; + incnt++; + + ret = virtqueue_add_sgs(priv->vq, sgs, outcnt, incnt, spi_req, + GFP_KERNEL); + +msg_done: + if (ret) + msg->status = ret; + + return ret; +} + +static int virtio_spi_transfer_one_message(struct spi_controller *ctrl, + struct spi_message *msg) +{ + struct virtio_spi_priv *priv = spi_controller_get_devdata(ctrl); + struct virtio_spi_req *spi_req; + struct spi_transfer *xfer; + int ret = 0; + + spi_req = kzalloc(sizeof(*spi_req), GFP_KERNEL); + if (!spi_req) { + ret = -ENOMEM; + goto no_mem; + } + + /* + * Simple implementation: Process message by message and wait for each + * message to be completed by the device side. + */ + list_for_each_entry(xfer, &msg->transfers, transfer_list) { + ret = virtio_spi_one_transfer(spi_req, ctrl, msg, xfer); + if (ret) + goto msg_done; + + virtqueue_kick(priv->vq); + + wait_for_completion(&spi_req->completion); + + /* Read result from message */ + ret = (int)spi_req->result.result; + if (ret) + goto msg_done; + } + +msg_done: + kfree(spi_req); +no_mem: + msg->status = ret; + spi_finalize_current_message(ctrl); + + return ret; +} + +static void virtio_spi_read_config(struct virtio_device *vdev) +{ + struct spi_controller *ctrl = dev_get_drvdata(&vdev->dev); + struct virtio_spi_priv *priv = vdev->priv; + u8 cs_max_number; + u8 tx_nbits_supported; + u8 rx_nbits_supported; + + cs_max_number = virtio_cread8(vdev, offsetof(struct virtio_spi_config, + cs_max_number)); + ctrl->num_chipselect = cs_max_number; + + /* Set the mode bits which are understood by this driver */ + priv->mode_func_supported = + virtio_cread32(vdev, offsetof(struct virtio_spi_config, + mode_func_supported)); + ctrl->mode_bits = priv->mode_func_supported & + (VIRTIO_SPI_CS_HIGH | VIRTIO_SPI_MODE_LSB_FIRST); + if ((priv->mode_func_supported & VIRTIO_SPI_MF_SUPPORT_CPHA_1) != 0) + ctrl->mode_bits |= VIRTIO_SPI_CPHA; + if ((priv->mode_func_supported & VIRTIO_SPI_MF_SUPPORT_CPOL_1) != 0) + ctrl->mode_bits |= VIRTIO_SPI_CPOL; + if ((priv->mode_func_supported & VIRTIO_SPI_MF_SUPPORT_LSB_FIRST) != 0) + ctrl->mode_bits |= SPI_LSB_FIRST; + if ((priv->mode_func_supported & VIRTIO_SPI_MF_SUPPORT_LOOPBACK) != 0) + ctrl->mode_bits |= SPI_LOOP; + tx_nbits_supported = + virtio_cread8(vdev, offsetof(struct virtio_spi_config, + tx_nbits_supported)); + if ((tx_nbits_supported & VIRTIO_SPI_RX_TX_SUPPORT_DUAL) != 0) + ctrl->mode_bits |= SPI_TX_DUAL; + if ((tx_nbits_supported & VIRTIO_SPI_RX_TX_SUPPORT_QUAD) != 0) + ctrl->mode_bits |= SPI_TX_QUAD; + if ((tx_nbits_supported & VIRTIO_SPI_RX_TX_SUPPORT_OCTAL) != 0) + ctrl->mode_bits |= SPI_TX_OCTAL; + rx_nbits_supported = + virtio_cread8(vdev, offsetof(struct virtio_spi_config, + rx_nbits_supported)); + if ((rx_nbits_supported & VIRTIO_SPI_RX_TX_SUPPORT_DUAL) != 0) + ctrl->mode_bits |= SPI_RX_DUAL; + if ((rx_nbits_supported & VIRTIO_SPI_RX_TX_SUPPORT_QUAD) != 0) + ctrl->mode_bits |= SPI_RX_QUAD; + if ((rx_nbits_supported & VIRTIO_SPI_RX_TX_SUPPORT_OCTAL) != 0) + ctrl->mode_bits |= SPI_RX_OCTAL; + + ctrl->bits_per_word_mask = + virtio_cread32(vdev, offsetof(struct virtio_spi_config, + bits_per_word_mask)); + + priv->max_freq_hz = + virtio_cread32(vdev, offsetof(struct virtio_spi_config, + max_freq_hz)); +} + +static int virtio_spi_find_vqs(struct virtio_spi_priv *priv) +{ + struct virtqueue *vq; + + vq = virtio_find_single_vq(priv->vdev, virtio_spi_msg_done, "spi-rq"); + if (IS_ERR(vq)) + return (int)PTR_ERR(vq); + priv->vq = vq; + return 0; +} + +/* Function must not be called before virtio_spi_find_vqs() has been run */ +static void virtio_spi_del_vq(struct virtio_device *vdev) +{ + virtio_reset_device(vdev); + vdev->config->del_vqs(vdev); +} + +static int virtio_spi_validate(struct virtio_device *vdev) +{ + /* + * SPI needs always access to the config space. + * Check that the driver can access the config space + */ + if (!vdev->config->get) { + dev_err(&vdev->dev, "%s failure: config access disabled\n", + __func__); + return -EINVAL; + } + + if (!virtio_has_feature(vdev, VIRTIO_F_VERSION_1)) { + dev_err(&vdev->dev, + "device does not comply with spec version 1.x\n"); + return -EINVAL; + } + + return 0; +} + +static int virtio_spi_probe(struct virtio_device *vdev) +{ + struct device_node *np = vdev->dev.parent->of_node; + struct virtio_spi_priv *priv; + struct spi_controller *ctrl; + int err; + u32 bus_num; + u16 csi; + + ctrl = devm_spi_alloc_host(&vdev->dev, sizeof(*priv)); + if (!ctrl) { + dev_err(&vdev->dev, "Kernel memory exhausted in %s()\n", + __func__); + err = -ENOMEM; + goto err_return; + } + + priv = spi_controller_get_devdata(ctrl); + priv->vdev = vdev; + vdev->priv = priv; + dev_set_drvdata(&vdev->dev, ctrl); + + err = of_property_read_u32(np, "spi,bus-num", &bus_num); + if (!err && bus_num <= S16_MAX) + ctrl->bus_num = (s16)bus_num; + + virtio_spi_read_config(vdev); + + /* Method to transfer a single SPI message */ + ctrl->transfer_one_message = virtio_spi_transfer_one_message; + + /* Initialize virtqueues */ + err = virtio_spi_find_vqs(priv); + if (err) { + dev_err(&vdev->dev, "Cannot setup virtqueues\n"); + goto err_return; + } + + err = spi_register_controller(ctrl); + if (err) { + dev_err(&vdev->dev, "Cannot register controller\n"); + goto err_return; + } + + board_info.max_speed_hz = priv->max_freq_hz; + /* spi_new_device() currently does not use bus_num but better set it */ + board_info.bus_num = (u16)ctrl->bus_num; + + /* Add chip selects to controller */ + for (csi = 0; csi < ctrl->num_chipselect; csi++) { + dev_dbg(&vdev->dev, "Setting up CS=%u\n", csi); + board_info.chip_select = csi; + /* TODO: Discuss setting of board_info.mode */ + if (!(priv->mode_func_supported & VIRTIO_SPI_CS_HIGH)) + board_info.mode = SPI_MODE_0; + else + board_info.mode = SPI_MODE_0 | SPI_CS_HIGH; + if (!spi_new_device(ctrl, &board_info)) { + dev_err(&vdev->dev, "Cannot setup device %u\n", csi); + err = -ENODEV; + goto err_return; + } + } + + return 0; + +err_return: + return err; +} + +static void virtio_spi_remove(struct virtio_device *vdev) +{ + struct spi_controller *ctrl = dev_get_drvdata(&vdev->dev); + + spi_unregister_controller(ctrl); + virtio_spi_del_vq(vdev); +} + +static int virtio_spi_freeze(struct virtio_device *vdev) +{ + struct device *dev = &vdev->dev; + struct spi_controller *ctrl = dev_get_drvdata(dev); + int ret; + + /* Stop the queue running */ + ret = spi_controller_suspend(ctrl); + if (ret) { + dev_warn(dev, "cannot suspend controller (%d)\n", ret); + return ret; + } + + virtio_spi_del_vq(vdev); + return 0; +} + +static int virtio_spi_restore(struct virtio_device *vdev) +{ + struct device *dev = &vdev->dev; + struct spi_controller *ctrl = dev_get_drvdata(dev); + int ret; + + ret = virtio_spi_find_vqs(vdev->priv); + if (ret) { + dev_err(dev, "problem starting vqueue (%d)\n", ret); + return ret; + } + + ret = spi_controller_resume(ctrl); + if (ret) + dev_err(dev, "problem resuming controller (%d)\n", ret); + + return ret; +} + +static struct virtio_device_id virtio_spi_id_table[] = { + { VIRTIO_ID_SPI, VIRTIO_DEV_ANY_ID }, + { 0 }, +}; + +static struct virtio_driver virtio_spi_driver = { + .driver.name = KBUILD_MODNAME, + .driver.owner = THIS_MODULE, + .id_table = virtio_spi_id_table, + .validate = virtio_spi_validate, + .probe = virtio_spi_probe, + .remove = virtio_spi_remove, + .freeze = pm_sleep_ptr(virtio_spi_freeze), + .restore = pm_sleep_ptr(virtio_spi_restore), +}; + +module_virtio_driver(virtio_spi_driver); +MODULE_DEVICE_TABLE(virtio, virtio_spi_id_table); + +MODULE_AUTHOR("OpenSynergy GmbH"); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Virtio SPI bus driver");