[2/5] i2c: sh_mobile: add DMA support

Message ID	1415355104-2031-3-git-send-email-wsa@the-dreams.de (mailing list archive)
State	Awaiting Upstream
Delegated to:	Geert Uytterhoeven
Headers	show Return-Path: <linux-sh-owner@kernel.org> From: Wolfram Sang <wsa@the-dreams.de> To: linux-i2c@vger.kernel.org Cc: linux-sh@vger.kernel.org, Wolfram Sang <wsa@the-dreams.de>, Magnus Damm <magnus.damm@gmail.com>, Simon Horman <horms@verge.net.au>, Laurent Pinchart <laurent.pinchart@ideasonboard.com>, Geert Uytterhoeven <geert@linux-m68k.org> Subject: [PATCH 2/5] i2c: sh_mobile: add DMA support Date: Fri, 7 Nov 2014 11:11:41 +0100 Message-Id: <1415355104-2031-3-git-send-email-wsa@the-dreams.de> In-Reply-To: <1415355104-2031-1-git-send-email-wsa@the-dreams.de> References: <1415355104-2031-1-git-send-email-wsa@the-dreams.de> Sender: linux-sh-owner@vger.kernel.org Precedence: bulk

diff --git a/Documentation/devicetree/bindings/i2c/i2c-sh_mobile.txt b/Documentation/devicetree/bindings/i2c/i2c-sh_mobile.txt index d2153ce36fa8..58dcf7d71e9c 100644 --- a/Documentation/devicetree/bindings/i2c/i2c-sh_mobile.txt +++ b/Documentation/devicetree/bindings/i2c/i2c-sh_mobile.txt @@ -10,6 +10,11 @@ Required properties: Optional properties: - clock-frequency : frequency of bus clock in Hz. Default 100kHz if unset. +- dmas : Must contain a list of two references to DMA + specifiers, one for transmission, and one for + reception. +- dma-names : Must contain a list of two DMA names, "tx" and "rx". + Pinctrl properties might be needed, too. See there. diff --git a/drivers/i2c/busses/i2c-sh_mobile.c b/drivers/i2c/busses/i2c-sh_mobile.c index 84efe09eb898..1e0aa597dd04 100644 --- a/drivers/i2c/busses/i2c-sh_mobile.c +++ b/drivers/i2c/busses/i2c-sh_mobile.c @@ -1,6 +1,8 @@ /* * SuperH Mobile I2C Controller * + * Copyright (C) 2014 Wolfram Sang <wsa@sang-engineering.com> + * * Copyright (C) 2008 Magnus Damm * * Portions of the code based on out-of-tree driver i2c-sh7343.c @@ -22,6 +24,8 @@ #include <linux/clk.h> #include <linux/delay.h> +#include <linux/dmaengine.h> +#include <linux/dma-mapping.h> #include <linux/err.h> #include <linux/i2c.h> #include <linux/i2c/i2c-sh_mobile.h> @@ -114,6 +118,7 @@ enum sh_mobile_i2c_op { OP_TX_FIRST, OP_TX, OP_TX_STOP, + OP_TX_STOP_DATA, OP_TX_TO_RX, OP_RX, OP_RX_STOP, @@ -138,6 +143,11 @@ struct sh_mobile_i2c_data { int pos; int sr; bool send_stop; + + struct dma_chan *dma_tx; + struct dma_chan *dma_rx; + struct scatterlist sg; + enum dma_data_direction dma_direction; }; struct sh_mobile_dt_config { @@ -175,6 +185,8 @@ struct sh_mobile_dt_config { #define ICIC_ICCLB8 0x80 #define ICIC_ICCHB8 0x40 +#define ICIC_TDMAE 0x20 +#define ICIC_RDMAE 0x10 #define ICIC_ALE 0x08 #define ICIC_TACKE 0x04 #define ICIC_WAITE 0x02 @@ -336,8 +348,10 @@ static unsigned char i2c_op(struct sh_mobile_i2c_data *pd, case OP_TX: /* write data */ iic_wr(pd, ICDR, data); break; - case OP_TX_STOP: /* write data and issue a stop afterwards */ + case OP_TX_STOP_DATA: /* write data and issue a stop afterwards */ iic_wr(pd, ICDR, data); + /* fallthrough */ + case OP_TX_STOP: /* issue a stop */ iic_wr(pd, ICCR, pd->send_stop ? ICCR_ICE | ICCR_TRS : ICCR_ICE | ICCR_TRS | ICCR_BBSY); break; @@ -393,13 +407,17 @@ static int sh_mobile_i2c_isr_tx(struct sh_mobile_i2c_data *pd) { unsigned char data; - if (pd->pos == pd->msg->len) + if (pd->pos == pd->msg->len) { + /* Send stop if we haven't yet (DMA case) */ + if (pd->send_stop && (iic_rd(pd, ICCR) & ICCR_BBSY)) + i2c_op(pd, OP_TX_STOP, data); return 1; + } sh_mobile_i2c_get_data(pd, &data); if (sh_mobile_i2c_is_last_byte(pd)) - i2c_op(pd, OP_TX_STOP, data); + i2c_op(pd, OP_TX_STOP_DATA, data); else if (sh_mobile_i2c_is_first_byte(pd)) i2c_op(pd, OP_TX_FIRST, data); else @@ -454,7 +472,7 @@ static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id) struct platform_device *dev = dev_id; struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev); unsigned char sr; - int wakeup; + int wakeup = 0; sr = iic_rd(pd, ICSR); pd->sr |= sr; /* remember state */ @@ -463,15 +481,21 @@ static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id) (pd->msg->flags & I2C_M_RD) ? "read" : "write", pd->pos, pd->msg->len); - if (sr & (ICSR_AL | ICSR_TACK)) { + /* Kick off TxDMA after preface was done */ + if (pd->dma_direction == DMA_TO_DEVICE && pd->pos == 0) + iic_set_clr(pd, ICIC, ICIC_TDMAE, 0); + else if (sr & (ICSR_AL | ICSR_TACK)) /* don't interrupt transaction - continue to issue stop */ iic_wr(pd, ICSR, sr & ~(ICSR_AL | ICSR_TACK)); - wakeup = 0; - } else if (pd->msg->flags & I2C_M_RD) + else if (pd->msg->flags & I2C_M_RD) wakeup = sh_mobile_i2c_isr_rx(pd); else wakeup = sh_mobile_i2c_isr_tx(pd); + /* Kick off RxDMA after preface was done */ + if (pd->dma_direction == DMA_FROM_DEVICE && pd->pos == 1) + iic_set_clr(pd, ICIC, ICIC_RDMAE, 0); + if (sr & ICSR_WAIT) /* TODO: add delay here to support slow acks */ iic_wr(pd, ICSR, sr & ~ICSR_WAIT); @@ -486,6 +510,79 @@ static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id) return IRQ_HANDLED; } +static void sh_mobile_i2c_cleanup_dma(struct sh_mobile_i2c_data *pd) +{ + if (pd->dma_direction == DMA_NONE) + return; + else if (pd->dma_direction == DMA_FROM_DEVICE) + dmaengine_terminate_all(pd->dma_rx); + else if (pd->dma_direction == DMA_TO_DEVICE) + dmaengine_terminate_all(pd->dma_tx); + + dma_unmap_single(pd->dev, sg_dma_address(&pd->sg), + pd->msg->len, pd->dma_direction); + + pd->dma_direction = DMA_NONE; +} + +static void sh_mobile_i2c_dma_callback(void *data) +{ + struct sh_mobile_i2c_data *pd = data; + + dma_unmap_single(pd->dev, sg_dma_address(&pd->sg), + pd->msg->len, pd->dma_direction); + + pd->dma_direction = DMA_NONE; + pd->pos = pd->msg->len; + + iic_set_clr(pd, ICIC, 0, ICIC_TDMAE | ICIC_RDMAE); +} + +static void sh_mobile_i2c_xfer_dma(struct sh_mobile_i2c_data *pd) +{ + bool read = pd->msg->flags & I2C_M_RD; + enum dma_data_direction dir = read ? DMA_FROM_DEVICE : DMA_TO_DEVICE; + struct dma_chan *chan = read ? pd->dma_rx : pd->dma_tx; + struct dma_async_tx_descriptor *txdesc; + dma_addr_t dma_addr; + dma_cookie_t cookie; + + if (!chan) + return; + + dma_addr = dma_map_single(pd->dev, pd->msg->buf, pd->msg->len, dir); + if (dma_mapping_error(pd->dev, dma_addr)) { + dev_dbg(pd->dev, "dma map failed, using PIO\n"); + return; + } + + sg_dma_len(&pd->sg) = pd->msg->len; + sg_dma_address(&pd->sg) = dma_addr; + + pd->dma_direction = dir; + + txdesc = dmaengine_prep_slave_sg(chan, &pd->sg, 1, + read ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!txdesc) { + dev_dbg(pd->dev, "dma prep slave sg failed, using PIO\n"); + sh_mobile_i2c_cleanup_dma(pd); + return; + } + + txdesc->callback = sh_mobile_i2c_dma_callback; + txdesc->callback_param = pd; + + cookie = dmaengine_submit(txdesc); + if (dma_submit_error(cookie)) { + dev_dbg(pd->dev, "submitting dma failed, using PIO\n"); + sh_mobile_i2c_cleanup_dma(pd); + return; + } + + dma_async_issue_pending(chan); +} + static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg, bool do_init) { @@ -510,6 +607,9 @@ static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg, pd->pos = -1; pd->sr = 0; + if (pd->msg->len > 8) + sh_mobile_i2c_xfer_dma(pd); + /* Enable all interrupts to begin with */ iic_wr(pd, ICIC, ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE); return 0; @@ -593,6 +693,9 @@ static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter, 5 * HZ); if (!k) { dev_err(pd->dev, "Transfer request timed out\n"); + if (pd->dma_direction != DMA_NONE) + sh_mobile_i2c_cleanup_dma(pd); + err = -ETIMEDOUT; break; } @@ -641,6 +744,62 @@ static const struct of_device_id sh_mobile_i2c_dt_ids[] = { }; MODULE_DEVICE_TABLE(of, sh_mobile_i2c_dt_ids); +static int sh_mobile_i2c_request_dma_chan(struct device *dev, enum dma_transfer_direction dir, + dma_addr_t port_addr, struct dma_chan **chan_ptr) +{ + dma_cap_mask_t mask; + struct dma_chan *chan; + struct dma_slave_config cfg; + char *chan_name = dir == DMA_MEM_TO_DEV ? "tx" : "rx"; + int ret; + + dma_cap_zero(mask); + dma_cap_set(DMA_SLAVE, mask); + *chan_ptr = NULL; + + chan = dma_request_slave_channel_reason(dev, chan_name); + if (IS_ERR(chan)) { + ret = PTR_ERR(chan); + dev_dbg(dev, "request_channel failed for %s (%d)\n", chan_name, ret); + return ret; + } + + memset(&cfg, 0, sizeof(cfg)); + cfg.direction = dir; + if (dir == DMA_MEM_TO_DEV) { + cfg.dst_addr = port_addr; + cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; + } else { + cfg.src_addr = port_addr; + cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; + } + + ret = dmaengine_slave_config(chan, &cfg); + if (ret) { + dev_dbg(dev, "slave_config failed for %s (%d)\n", chan_name, ret); + dma_release_channel(chan); + return ret; + } + + *chan_ptr = chan; + + dev_dbg(dev, "got DMA channel for %s\n", chan_name); + return 0; +} + +static void sh_mobile_i2c_release_dma(struct sh_mobile_i2c_data *pd) +{ + if (pd->dma_tx) { + dma_release_channel(pd->dma_tx); + pd->dma_tx = NULL; + } + + if (pd->dma_rx) { + dma_release_channel(pd->dma_rx); + pd->dma_rx = NULL; + } +} + static int sh_mobile_i2c_hook_irqs(struct platform_device *dev) { struct resource *res; @@ -727,6 +886,21 @@ static int sh_mobile_i2c_probe(struct platform_device *dev) if (ret) return ret; + /* Init DMA */ + sg_init_table(&pd->sg, 1); + pd->dma_direction = DMA_NONE; + ret = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_DEV_TO_MEM, + res->start + ICDR, &pd->dma_rx); + if (ret == -EPROBE_DEFER) + return ret; + + ret = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_MEM_TO_DEV, + res->start + ICDR, &pd->dma_tx); + if (ret == -EPROBE_DEFER) { + sh_mobile_i2c_release_dma(pd); + return ret; + } + /* Enable Runtime PM for this device. * * Also tell the Runtime PM core to ignore children @@ -758,6 +932,7 @@ static int sh_mobile_i2c_probe(struct platform_device *dev) ret = i2c_add_numbered_adapter(adap); if (ret < 0) { + sh_mobile_i2c_release_dma(pd); dev_err(&dev->dev, "cannot add numbered adapter\n"); return ret; } @@ -774,6 +949,7 @@ static int sh_mobile_i2c_remove(struct platform_device *dev) struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev); i2c_del_adapter(&pd->adap); + sh_mobile_i2c_release_dma(pd); pm_runtime_disable(&dev->dev); return 0; } @@ -810,16 +986,15 @@ static int __init sh_mobile_i2c_adap_init(void) { return platform_driver_register(&sh_mobile_i2c_driver); } +subsys_initcall(sh_mobile_i2c_adap_init); static void __exit sh_mobile_i2c_adap_exit(void) { platform_driver_unregister(&sh_mobile_i2c_driver); } - -subsys_initcall(sh_mobile_i2c_adap_init); module_exit(sh_mobile_i2c_adap_exit); MODULE_DESCRIPTION("SuperH Mobile I2C Bus Controller driver"); -MODULE_AUTHOR("Magnus Damm"); +MODULE_AUTHOR("Magnus Damm and Wolfram Sang"); MODULE_LICENSE("GPL v2"); MODULE_ALIAS("platform:i2c-sh_mobile");

[2/5] i2c: sh_mobile: add DMA support

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