@@ -140,3 +140,10 @@ config IBMEBUS
bool "Support for GX bus based adapters"
help
Bus device driver for GX bus based adapters.
+
+config PAPR_SCM
+ depends on PPC_PSERIES && MEMORY_HOTPLUG
+ select LIBNVDIMM
+ tristate "Support for the PAPR Storage Class Memory interface"
+ help
+ Enable access to hypervisor provided storage class memory.
@@ -24,6 +24,7 @@ obj-$(CONFIG_IO_EVENT_IRQ) += io_event_irq.o
obj-$(CONFIG_LPARCFG) += lparcfg.o
obj-$(CONFIG_IBMVIO) += vio.o
obj-$(CONFIG_IBMEBUS) += ibmebus.o
+obj-$(CONFIG_PAPR_SCM) += papr_scm.o
ifdef CONFIG_PPC_PSERIES
obj-$(CONFIG_SUSPEND) += suspend.o
new file mode 100644
@@ -0,0 +1,345 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define pr_fmt(fmt) "papr-scm: " fmt
+
+#include <linux/of.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/ioport.h>
+#include <linux/slab.h>
+#include <linux/ndctl.h>
+#include <linux/sched.h>
+#include <linux/libnvdimm.h>
+#include <linux/platform_device.h>
+
+#include <asm/plpar_wrappers.h>
+
+#define BIND_ANY_ADDR (~0ul)
+
+#define PAPR_SCM_DIMM_CMD_MASK \
+ ((1ul << ND_CMD_GET_CONFIG_SIZE) | \
+ (1ul << ND_CMD_GET_CONFIG_DATA) | \
+ (1ul << ND_CMD_SET_CONFIG_DATA))
+
+struct papr_scm_priv {
+ struct platform_device *pdev;
+ struct device_node *dn;
+ uint32_t drc_index;
+ uint64_t blocks;
+ uint64_t block_size;
+ int metadata_size;
+
+ uint64_t bound_addr;
+
+ struct nvdimm_bus_descriptor bus_desc;
+ struct nvdimm_bus *bus;
+ struct nvdimm *nvdimm;
+ struct resource res;
+ struct nd_region *region;
+ struct nd_interleave_set nd_set;
+};
+
+static int drc_pmem_bind(struct papr_scm_priv *p)
+{
+ unsigned long ret[PLPAR_HCALL_BUFSIZE];
+ uint64_t rc, token;
+
+ /*
+ * When the hypervisor cannot map all the requested memory in a single
+ * hcall it returns H_BUSY and we call again with the token until
+ * we get H_SUCCESS. Aborting the retry loop before getting H_SUCCESS
+ * leave the system in an undefined state, so we wait.
+ */
+ token = 0;
+
+ do {
+ rc = plpar_hcall(H_SCM_BIND_MEM, ret, p->drc_index, 0,
+ p->blocks, BIND_ANY_ADDR, token);
+ token = be64_to_cpu(ret[0]);
+ cond_resched();
+ } while (rc == H_BUSY);
+
+ if (rc) {
+ dev_err(&p->pdev->dev, "bind err: %lld\n", rc);
+ return -ENXIO;
+ }
+
+ p->bound_addr = be64_to_cpu(ret[1]);
+
+ dev_dbg(&p->pdev->dev, "bound drc %x to %pR\n", p->drc_index, &p->res);
+
+ return 0;
+}
+
+static int drc_pmem_unbind(struct papr_scm_priv *p)
+{
+ unsigned long ret[PLPAR_HCALL_BUFSIZE];
+ uint64_t rc, token;
+
+ token = 0;
+
+ /* NB: unbind has the same retry requirements mentioned above */
+ do {
+ rc = plpar_hcall(H_SCM_UNBIND_MEM, ret, p->drc_index,
+ p->bound_addr, p->blocks, token);
+ token = be64_to_cpu(ret);
+ cond_resched();
+ } while (rc == H_BUSY);
+
+ if (rc)
+ dev_err(&p->pdev->dev, "unbind error: %lld\n", rc);
+
+ return !!rc;
+}
+
+static int papr_scm_meta_get(struct papr_scm_priv *p,
+ struct nd_cmd_get_config_data_hdr *hdr)
+{
+ unsigned long data[PLPAR_HCALL_BUFSIZE];
+ int64_t ret;
+
+ if (hdr->in_offset >= p->metadata_size || hdr->in_length != 1)
+ return -EINVAL;
+
+ ret = plpar_hcall(H_SCM_READ_METADATA, data, p->drc_index,
+ hdr->in_offset, 1);
+
+ if (ret == H_PARAMETER) /* bad DRC index */
+ return -ENODEV;
+ if (ret)
+ return -EINVAL; /* other invalid parameter */
+
+ hdr->out_buf[0] = data[0] & 0xff;
+
+ return 0;
+}
+
+static int papr_scm_meta_set(struct papr_scm_priv *p,
+ struct nd_cmd_set_config_hdr *hdr)
+{
+ int64_t ret;
+
+ if (hdr->in_offset >= p->metadata_size || hdr->in_length != 1)
+ return -EINVAL;
+
+ ret = plpar_hcall_norets(H_SCM_WRITE_METADATA,
+ p->drc_index, hdr->in_offset, hdr->in_buf[0], 1);
+
+ if (ret == H_PARAMETER) /* bad DRC index */
+ return -ENODEV;
+ if (ret)
+ return -EINVAL; /* other invalid parameter */
+
+ return 0;
+}
+
+int papr_scm_ndctl(struct nvdimm_bus_descriptor *nd_desc, struct nvdimm *nvdimm,
+ unsigned int cmd, void *buf, unsigned int buf_len, int *cmd_rc)
+{
+ struct nd_cmd_get_config_size *get_size_hdr;
+ struct papr_scm_priv *p;
+
+ /* Only dimm-specific calls are supported atm */
+ if (!nvdimm)
+ return -EINVAL;
+
+ p = nvdimm_provider_data(nvdimm);
+
+ switch (cmd) {
+ case ND_CMD_GET_CONFIG_SIZE:
+ get_size_hdr = buf;
+
+ get_size_hdr->status = 0;
+ get_size_hdr->max_xfer = 1;
+ get_size_hdr->config_size = p->metadata_size;
+ *cmd_rc = 0;
+ break;
+
+ case ND_CMD_GET_CONFIG_DATA:
+ *cmd_rc = papr_scm_meta_get(p, buf);
+ break;
+
+ case ND_CMD_SET_CONFIG_DATA:
+ *cmd_rc = papr_scm_meta_set(p, buf);
+ break;
+
+ default:
+ return -EINVAL;
+ }
+
+ dev_dbg(&p->pdev->dev, "returned with cmd_rc = %d\n", *cmd_rc);
+
+ return 0;
+}
+
+static const struct attribute_group *region_attr_groups[] = {
+ &nd_region_attribute_group,
+ &nd_device_attribute_group,
+ &nd_mapping_attribute_group,
+ &nd_numa_attribute_group,
+ NULL,
+};
+
+static const struct attribute_group *bus_attr_groups[] = {
+ &nvdimm_bus_attribute_group,
+ NULL,
+};
+
+static const struct attribute_group *papr_scm_dimm_groups[] = {
+ &nvdimm_attribute_group,
+ &nd_device_attribute_group,
+ NULL,
+};
+
+static int papr_scm_nvdimm_init(struct papr_scm_priv *p)
+{
+ struct device *dev = &p->pdev->dev;
+ struct nd_mapping_desc mapping;
+ struct nd_region_desc ndr_desc;
+ unsigned long dimm_flags;
+
+ p->bus_desc.ndctl = papr_scm_ndctl;
+ p->bus_desc.module = THIS_MODULE;
+ p->bus_desc.of_node = p->pdev->dev.of_node;
+ p->bus_desc.attr_groups = bus_attr_groups;
+ p->bus_desc.provider_name = kstrdup(p->pdev->name, GFP_KERNEL);
+
+ if (!p->bus_desc.provider_name)
+ return -ENOMEM;
+
+ p->bus = nvdimm_bus_register(NULL, &p->bus_desc);
+ if (!p->bus) {
+ dev_err(dev, "Error creating nvdimm bus %pOF\n", p->dn);
+ return -ENXIO;
+ }
+
+ dimm_flags = 0;
+ set_bit(NDD_ALIASING, &dimm_flags);
+
+ p->nvdimm = nvdimm_create(p->bus, p, papr_scm_dimm_groups,
+ dimm_flags, PAPR_SCM_DIMM_CMD_MASK, 0, NULL);
+ if (!p->nvdimm) {
+ dev_err(dev, "Error creating DIMM object for %pOF\n", p->dn);
+ goto err;
+ }
+
+ /* now add the region */
+
+ memset(&mapping, 0, sizeof(mapping));
+ mapping.nvdimm = p->nvdimm;
+ mapping.start = 0;
+ mapping.size = p->blocks * p->block_size; // XXX: potential overflow?
+
+ memset(&ndr_desc, 0, sizeof(ndr_desc));
+ ndr_desc.attr_groups = region_attr_groups;
+ ndr_desc.numa_node = dev_to_node(&p->pdev->dev);
+ ndr_desc.res = &p->res;
+ ndr_desc.of_node = p->dn;
+ ndr_desc.provider_data = p;
+ ndr_desc.mapping = &mapping;
+ ndr_desc.num_mappings = 1;
+ ndr_desc.nd_set = &p->nd_set;
+ set_bit(ND_REGION_PAGEMAP, &ndr_desc.flags);
+
+ p->region = nvdimm_pmem_region_create(p->bus, &ndr_desc);
+ if (!p->region) {
+ dev_err(dev, "Error registering region %pR from %pOF\n",
+ ndr_desc.res, p->dn);
+ goto err;
+ }
+
+ return 0;
+
+err: nvdimm_bus_unregister(p->bus);
+ kfree(p->bus_desc.provider_name);
+ return -ENXIO;
+}
+
+static int papr_scm_probe(struct platform_device *pdev)
+{
+ uint32_t drc_index, metadata_size, unit_cap[2];
+ struct device_node *dn = pdev->dev.of_node;
+ struct papr_scm_priv *p;
+ int rc;
+
+ /* check we have all the required DT properties */
+ if (of_property_read_u32(dn, "ibm,my-drc-index", &drc_index)) {
+ dev_err(&pdev->dev, "%pOF: missing drc-index!\n", dn);
+ return -ENODEV;
+ }
+
+ if (of_property_read_u32_array(dn, "ibm,unit-capacity", unit_cap, 2)) {
+ dev_err(&pdev->dev, "%pOF: missing unit-capacity!\n", dn);
+ return -ENODEV;
+ }
+
+ p = kzalloc(sizeof(*p), GFP_KERNEL);
+ if (!p)
+ return -ENOMEM;
+
+ /* optional DT properties */
+ of_property_read_u32(dn, "ibm,metadata-size", &metadata_size);
+
+ p->dn = dn;
+ p->drc_index = drc_index;
+ p->block_size = unit_cap[0];
+ p->blocks = unit_cap[1];
+
+ /* might be zero */
+ p->metadata_size = metadata_size;
+ p->pdev = pdev;
+
+ /* request the hypervisor to bind this region to somewhere in memory */
+ rc = drc_pmem_bind(p);
+ if (rc)
+ goto err;
+
+ /* setup the resource for the newly bound range */
+ p->res.start = p->bound_addr;
+ p->res.end = p->bound_addr + p->blocks * p->block_size;
+ p->res.name = pdev->name;
+ p->res.flags = IORESOURCE_MEM;
+
+ rc = papr_scm_nvdimm_init(p);
+ if (rc)
+ goto err2;
+
+ platform_set_drvdata(pdev, p);
+
+ return 0;
+
+err2: drc_pmem_unbind(p);
+err: kfree(p);
+ return rc;
+}
+
+static int papr_scm_remove(struct platform_device *pdev)
+{
+ struct papr_scm_priv *p = platform_get_drvdata(pdev);
+
+ nvdimm_bus_unregister(p->bus);
+ drc_pmem_unbind(p);
+ kfree(p);
+
+ return 0;
+}
+
+static const struct of_device_id papr_scm_match[] = {
+ { .compatible = "ibm,pmemory" },
+ { },
+};
+
+static struct platform_driver papr_scm_driver = {
+ .probe = papr_scm_probe,
+ .remove = papr_scm_remove,
+ .driver = {
+ .name = "papr_scm",
+ .owner = THIS_MODULE,
+ .of_match_table = papr_scm_match,
+ },
+};
+
+module_platform_driver(papr_scm_driver);
+MODULE_DEVICE_TABLE(of, papr_scm_match);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("IBM Corporation");
Adds a driver that implements support for enabling and accessing PAPR SCM regions. Unfortunately due to how the PAPR interface works we can't use the existing of_pmem driver (yet) because: a) The guest is required to use the H_SCM_BIND_MEM h-call to add add the SCM region to it's physical address space, and b) There is currently no mechanism for relating a bare of_pmem region to the backing DIMM (or not-a-DIMM for our case). Both of these are easily handled by rolling the functionality into a seperate driver so here we are... Acked-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Oliver O'Halloran <oohall@gmail.com> --- The alternative implementation here is that we have the pseries code do the h-calls and craft a pmem-region@<addr> node based on that. However, that doesn't solve b) and mpe has expressed his dislike of adding new stuff to the DT at runtime so i'd say that's a non-starter. --- v2: no change v3: Corrected the mapping to use a DPA start address of zero Added cond_resched() calls in the bind/unbind loops --- arch/powerpc/platforms/pseries/Kconfig | 7 + arch/powerpc/platforms/pseries/Makefile | 1 + arch/powerpc/platforms/pseries/papr_scm.c | 345 ++++++++++++++++++++++++++++++ 3 files changed, 353 insertions(+) create mode 100644 arch/powerpc/platforms/pseries/papr_scm.c