On Mon, Nov 11, 2019 at 9:37 PM Dan Williams [off-list ref] wrote:

On Mon, Nov 11, 2019 at 3:34 AM Aneesh Kumar K.V
[off-list ref] wrote:

quoted

"Alastair D'Silva" [off-list ref] writes:

quoted

From: Alastair D'Silva <redacted>

This driver exposes LPC memory on OpenCAPI SCM cards
as an NVDIMM, allowing the existing nvram infrastructure
to be used.

Signed-off-by: Alastair D'Silva <redacted>
---
 drivers/nvdimm/Kconfig             |   17 +
 drivers/nvdimm/Makefile            |    3 +
 drivers/nvdimm/ocxl-scm.c          | 2210 ++++++++++++++++++++++++++++
 drivers/nvdimm/ocxl-scm_internal.c |  232 +++
 drivers/nvdimm/ocxl-scm_internal.h |  331 +++++
 drivers/nvdimm/ocxl-scm_sysfs.c    |  219 +++
 include/uapi/linux/ocxl-scm.h      |  128 ++
 mm/memory_hotplug.c                |    2 +-
 8 files changed, 3141 insertions(+), 1 deletion(-)
 create mode 100644 drivers/nvdimm/ocxl-scm.c
 create mode 100644 drivers/nvdimm/ocxl-scm_internal.c
 create mode 100644 drivers/nvdimm/ocxl-scm_internal.h
 create mode 100644 drivers/nvdimm/ocxl-scm_sysfs.c
 create mode 100644 include/uapi/linux/ocxl-scm.h

diff --git a/drivers/nvdimm/Kconfig b/drivers/nvdimm/Kconfig
index 36af7af6b7cf..e4f7b6b08efd 100644
--- a/drivers/nvdimm/Kconfig
+++ b/drivers/nvdimm/Kconfig

@@ -130,4 +130,21 @@ config NVDIMM_TEST_BUILD
        core devm_memremap_pages() implementation and other
        infrastructure.

+config OCXL_SCM
+     tristate "OpenCAPI Storage Class Memory"
+     depends on LIBNVDIMM
+     select ZONE_DEVICE
+     select OCXL
+     help
+       Exposes devices that implement the OpenCAPI Storage Class Memory
+       specification as persistent memory regions.
+
+       Select N if unsure.
+
+config OCXL_SCM_DEBUG
+     bool "OpenCAPI Storage Class Memory debugging"
+     depends on OCXL_SCM
+     help
+       Enables low level IOCTLs for OpenCAPI SCM firmware development
+
 endif

diff --git a/drivers/nvdimm/Makefile b/drivers/nvdimm/Makefile
index 29203f3d3069..43d826397bfc 100644
--- a/drivers/nvdimm/Makefile
+++ b/drivers/nvdimm/Makefile

@@ -6,6 +6,9 @@ obj-$(CONFIG_ND_BLK) += nd_blk.o
 obj-$(CONFIG_X86_PMEM_LEGACY) += nd_e820.o
 obj-$(CONFIG_OF_PMEM) += of_pmem.o
 obj-$(CONFIG_VIRTIO_PMEM) += virtio_pmem.o nd_virtio.o
+obj-$(CONFIG_OCXL_SCM) += ocxlscm.o
+
+ocxlscm-y := ocxl-scm.o ocxl-scm_internal.o ocxl-scm_sysfs.o

 nd_pmem-y := pmem.o

diff --git a/drivers/nvdimm/ocxl-scm.c b/drivers/nvdimm/ocxl-scm.c
new file mode 100644
index 000000000000..f4e6cc022de8
--- /dev/null
+++ b/drivers/nvdimm/ocxl-scm.c

how about drivers/nvdimm/ocxl/scm.c ? Or may be place the driver as an
ocxl driver.

quoted

@@ -0,0 +1,2210 @@
+// SPDX-License-Identifier: GPL-2.0+
+// Copyright 2019 IBM Corp.
+
+/*
+ * A driver for Storage Class Memory, connected via OpenCAPI
+ */
+
+#include <linux/module.h>
+#include <misc/ocxl.h>
+#include <linux/delay.h>
+#include <linux/ndctl.h>
+#include <linux/eventfd.h>
+#include <linux/fs.h>
+#include <linux/mm_types.h>
+#include <linux/memory_hotplug.h>
+#include "ocxl-scm_internal.h"
+
+
+static const struct pci_device_id scm_pci_tbl[] = {
+     { PCI_DEVICE(PCI_VENDOR_ID_IBM, 0x0625), },
+     { }
+};
+
+MODULE_DEVICE_TABLE(pci, scm_pci_tbl);
+
+#define SCM_NUM_MINORS 256 // Total to reserve
+#define SCM_USABLE_TIMEOUT 120 // seconds
+
+static dev_t scm_dev;
+static struct class *scm_class;
+static struct mutex minors_idr_lock;
+static struct idr minors_idr;
+
+static const struct attribute_group *scm_pmem_attribute_groups[] = {
+     &nvdimm_bus_attribute_group,
+     NULL,
+};
+
+static const struct attribute_group *scm_pmem_region_attribute_groups[] = {
+     &nd_region_attribute_group,
+     &nd_device_attribute_group,
+     &nd_mapping_attribute_group,
+     &nd_numa_attribute_group,
+     NULL,
+};
+

There is another patch series that is moving this from device driver to
nvdimm core.

https://lore.kernel.org/linux-mm/157309899529.1582359.15358067933360719580.stgit@dwillia2-desk3.amr.corp.intel.com (local)

quoted

+/**
+ * scm_ndctl_config_write() - Handle a ND_CMD_SET_CONFIG_DATA command from ndctl
+ * @scm_data: the SCM metadata
+ * @command: the incoming data to write
+ * Return: 0 on success, negative on failure
+ */
+static int scm_ndctl_config_write(struct scm_data *scm_data,
+                               struct nd_cmd_set_config_hdr *command)
+{
+     if (command->in_offset + command->in_length > SCM_LABEL_AREA_SIZE)
+             return -EINVAL;
+
+     memcpy_flushcache(scm_data->metadata_addr + command->in_offset, command->in_buf,
+                       command->in_length);
+
+     return 0;
+}
+
+/**
+ * scm_ndctl_config_read() - Handle a ND_CMD_GET_CONFIG_DATA command from ndctl
+ * @scm_data: the SCM metadata
+ * @command: the read request
+ * Return: 0 on success, negative on failure
+ */
+static int scm_ndctl_config_read(struct scm_data *scm_data,
+                              struct nd_cmd_get_config_data_hdr *command)
+{
+     if (command->in_offset + command->in_length > SCM_LABEL_AREA_SIZE)
+             return -EINVAL;
+
+     memcpy(command->out_buf, scm_data->metadata_addr + command->in_offset,
+            command->in_length);
+

memcpy_mcsafe()?

quoted

+     return 0;
+}
+
+/**
+ * scm_ndctl_config_size() - Handle a ND_CMD_GET_CONFIG_SIZE command from ndctl
+ * @scm_data: the SCM metadata
+ * @command: the read request
+ * Return: 0 on success, negative on failure
+ */
+static int scm_ndctl_config_size(struct nd_cmd_get_config_size *command)
+{
+     command->status = 0;
+     command->config_size = SCM_LABEL_AREA_SIZE;
+     command->max_xfer = PAGE_SIZE;
+
+     return 0;
+}
+
+static int read_smart_attrib(struct scm_data *scm_data, u16 offset,
+                          struct scm_smart_attribs *attribs)
+{
+     u64 val;
+     int rc;
+     struct scm_smart_attrib *attrib;
+     u8 attrib_id;
+
+     rc = ocxl_global_mmio_read64(scm_data->ocxl_afu, offset, OCXL_LITTLE_ENDIAN,
+                                  &val);
+     if (rc)
+             return rc;
+
+     attrib_id = (val >> 56) & 0xff;
+     switch (attrib_id) {
+     case SCM_SMART_ATTR_POWER_ON_HOURS:
+             attrib = &attribs->power_on_hours;
+             break;
+
+     case SCM_SMART_ATTR_TEMPERATURE:
+             attrib = &attribs->temperature;
+             break;
+
+     case SCM_SMART_ATTR_LIFE_REMAINING:
+             attrib = &attribs->life_remaining;
+             break;
+
+     default:
+             dev_err(&scm_data->dev, "Unknown smart attrib '%d'", attrib_id);
+             return -EFAULT;
+     }
+
+     attrib->id = attrib_id;
+     attrib->attribute_flags = (val >> 40) & 0xffff;
+     attrib->current_val = (val >> 32) & 0xff;
+     attrib->threshold_val = (val >> 24) & 0xff;
+     attrib->worst_val = (val >> 16) & 0xff;
+
+     rc = ocxl_global_mmio_read64(scm_data->ocxl_afu, offset + 0x08,
+                                  OCXL_LITTLE_ENDIAN, &val);
+     if (rc)
+             return rc;
+
+     attrib->raw_val = val;
+
+     return 0;
+}
+
+static int scm_smart_offset_0x00(struct scm_data *scm_data, u32 *length)
+'

What is special about _0x00?

{

quoted

+     int rc;
+     u64 val;
+
+     u16 data_identifier;
+     u32 data_length;
+
+     rc = ocxl_global_mmio_read64(scm_data->ocxl_afu,
+                                  scm_data->admin_command.data_offset,
+                                  OCXL_LITTLE_ENDIAN, &val);
+     if (rc)
+             return rc;
+
+     data_identifier = val >> 48;
+     data_length = val & 0xFFFFFFFF;
+
+     if (data_identifier != 0x534D) {
+             dev_err(&scm_data->dev,
+                     "Bad data identifier for smart data, expected 'SM', got '%-.*s'\n",
+                     2, (char *)&data_identifier);
+             return -EFAULT;
+     }
+
+     *length = data_length;
+     return 0;
+}
+
+static int scm_smart_update(struct scm_data *scm_data)
+{
+     u32 length, i;
+     int rc;
+
+     mutex_lock(&scm_data->admin_command.lock);
+
+     rc = scm_admin_command_request(scm_data, ADMIN_COMMAND_SMART);
+     if (rc)
+             goto out;
+
+     rc = scm_admin_command_execute(scm_data);
+     if (rc)
+             goto out;
+
+     rc = scm_admin_command_complete_timeout(scm_data, ADMIN_COMMAND_SMART);
+     if (rc < 0) {
+             dev_err(&scm_data->dev, "SMART timeout\n");
+             goto out;
+     }
+
+     rc = scm_admin_response(scm_data);
+     if (rc < 0)
+             goto out;
+     if (rc != STATUS_SUCCESS) {
+             scm_warn_status(scm_data, "Unexpected status from SMART", rc);
+             goto out;
+     }
+
+     rc = scm_smart_offset_0x00(scm_data, &length);
+     if (rc)
+             goto out;
+
+     length /= 0x10; // Length now contains the number of attributes
+
+     for (i = 0; i < length; i++)
+             read_smart_attrib(scm_data,
+                               scm_data->admin_command.data_offset + 0x08 + i * 0x10,
+                               &scm_data->smart);
+
+     rc = scm_admin_response_handled(scm_data);
+     if (rc)
+             goto out;
+
+     rc = 0;
+     goto out;
+
+out:
+     mutex_unlock(&scm_data->admin_command.lock);
+     return rc;
+}
+
+static int scm_ndctl_smart(struct scm_data *scm_data, void *buf,
+                        unsigned int buf_len)
+{
+     int rc;
+
+     if (buf_len != sizeof(scm_data->smart))
+             return -EINVAL;
+
+     rc = scm_smart_update(scm_data);
+     if (rc)
+             return rc;
+
+     memcpy(buf, &scm_data->smart, buf_len);
+
+     return 0;
+}
+
+
+static int scm_ndctl(struct nvdimm_bus_descriptor *nd_desc,
+                  struct nvdimm *nvdimm,
+                  unsigned int cmd, void *buf, unsigned int buf_len, int *cmd_rc)
+{
+     struct scm_data *scm_data = container_of(nd_desc, struct scm_data, bus_desc);
+
+     switch (cmd) {
+     case ND_CMD_SMART:
+             *cmd_rc = scm_ndctl_smart(scm_data, buf, buf_len);
+             return 0;
+
+     case ND_CMD_GET_CONFIG_SIZE:
+             *cmd_rc = scm_ndctl_config_size(buf);
+             return 0;
+
+     case ND_CMD_GET_CONFIG_DATA:
+             *cmd_rc = scm_ndctl_config_read(scm_data, buf);
+             return 0;
+
+     case ND_CMD_SET_CONFIG_DATA:
+             *cmd_rc = scm_ndctl_config_write(scm_data, buf);
+             return 0;
+
+     default:
+             return -ENOTTY;
+     }
+}
+
+static ssize_t serial_show(struct device *dev,
+                        struct device_attribute *attr, char *buf)
+{
+     struct nvdimm *nvdimm = to_nvdimm(dev);
+     struct scm_data *scm_data = nvdimm_provider_data(nvdimm);
+     const struct ocxl_fn_config *config = ocxl_function_config(scm_data->ocxl_fn);
+
+     return sprintf(buf, "0x%llx\n", config->serial);
+}
+static DEVICE_ATTR_RO(serial);
+
+static struct attribute *scm_dimm_attributes[] = {
+     &dev_attr_serial.attr,
+     NULL,
+};
+
+static umode_t scm_dimm_attr_visible(struct kobject *kobj,
+                                  struct attribute *a, int n)
+{
+     return a->mode;
+}
+
+static const struct attribute_group scm_dimm_attribute_group = {
+     .name = "scm",
+     .attrs = scm_dimm_attributes,
+     .is_visible = scm_dimm_attr_visible,
+};
+

That is a generic name for dimm attribute

quoted

+static const struct attribute_group *scm_dimm_attribute_groups[] = {
+     &nvdimm_attribute_group,
+     &nd_device_attribute_group,
+     &scm_dimm_attribute_group,
+     NULL,
+};
+
+/**
+ * scm_reserve_metadata() - Reserve space for nvdimm metadata
+ * @scm_data: The SCM device data
+ * @lpc_mem: The resource representing the LPC memory of the SCM device
+ */
+static int scm_reserve_metadata(struct scm_data *scm_data,
+                             struct resource *lpc_mem)
+{
+     scm_data->metadata_addr = devm_memremap(&scm_data->dev, lpc_mem->start,
+                                             SCM_LABEL_AREA_SIZE, MEMREMAP_WB);
+     if (IS_ERR(scm_data->metadata_addr))
+             return PTR_ERR(scm_data->metadata_addr);
+
+     return 0;
+}
+
+/**
+ * scm_overwrite() - Overwrite all data on the card
+ * @scm_data: The SCM device data
+ * Return: 0 on success
+ */
+int scm_overwrite(struct scm_data *scm_data)
+{
+     int rc;
+
+     mutex_lock(&scm_data->ns_command.lock);
+
+     rc = scm_ns_command_request(scm_data, NS_COMMAND_SECURE_ERASE);
+     if (rc)
+             goto out;
+
+     rc = scm_ns_command_execute(scm_data);
+     if (rc)
+             goto out;
+
+     scm_data->overwrite_state = SCM_OVERWRITE_BUSY;
+
+     return 0;
+
+out:
+     mutex_unlock(&scm_data->ns_command.lock);
+     return rc;
+}
+
+/**
+ * scm_secop_overwrite() - Overwrite all data on the card
+ * @nvdimm: The nvdimm representation of the SCM device to start the overwrite on
+ * @key_data: Unused (no security key implementation)
+ * Return: 0 on success
+ */
+static int scm_secop_overwrite(struct nvdimm *nvdimm,
+                            const struct nvdimm_key_data *key_data)
+{
+     struct scm_data *scm_data = nvdimm_provider_data(nvdimm);
+
+     return scm_overwrite(scm_data);
+}
+
+/**
+ * scm_secop_query_overwrite() - Get the current overwrite state
+ * @nvdimm: The nvdimm representation of the SCM device to start the overwrite on
+ * Return: 0 if successful or idle, -EBUSY if busy, -EFAULT if failed
+ */
+static int scm_secop_query_overwrite(struct nvdimm *nvdimm)
+{
+     struct scm_data *scm_data = nvdimm_provider_data(nvdimm);
+
+     if (scm_data->overwrite_state == SCM_OVERWRITE_BUSY)
+             return -EBUSY;
+
+     if (scm_data->overwrite_state == SCM_OVERWRITE_FAILED)
+             return -EFAULT;
+
+     return 0;
+}
+
+/**
+ * scm_secop_get_flags() - return the security flags for the SCM device
+ */
+static unsigned long scm_secop_get_flags(struct nvdimm *nvdimm,
+             enum nvdimm_passphrase_type ptype)
+{
+     struct scm_data *scm_data = nvdimm_provider_data(nvdimm);
+
+     if (scm_data->overwrite_state == SCM_OVERWRITE_BUSY)
+             return BIT(NVDIMM_SECURITY_OVERWRITE);
+
+     return BIT(NVDIMM_SECURITY_DISABLED);
+}
+
+static const struct nvdimm_security_ops sec_ops  = {
+     .get_flags = scm_secop_get_flags,
+     .overwrite = scm_secop_overwrite,
+     .query_overwrite = scm_secop_query_overwrite,
+};
+
+/**
+ * scm_register_lpc_mem() - Discover persistent memory on a device and register it with the NVDIMM subsystem
+ * @scm_data: The SCM device data
+ * Return: 0 on success
+ */
+static int scm_register_lpc_mem(struct scm_data *scm_data)
+{
+     struct nd_region_desc region_desc;
+     struct nd_mapping_desc nd_mapping_desc;
+     struct resource *lpc_mem;
+     const struct ocxl_afu_config *config;
+     const struct ocxl_fn_config *fn_config;
+     int rc;
+     unsigned long nvdimm_cmd_mask = 0;
+     unsigned long nvdimm_flags = 0;
+     int target_node;
+     char serial[16+1];
+
+     // Set up the reserved metadata area
+     rc = ocxl_afu_map_lpc_mem(scm_data->ocxl_afu);
+     if (rc < 0)
+             return rc;
+
+     lpc_mem = ocxl_afu_lpc_mem(scm_data->ocxl_afu);
+     if (lpc_mem == NULL)
+             return -EINVAL;
+
+     config = ocxl_afu_config(scm_data->ocxl_afu);
+     fn_config = ocxl_function_config(scm_data->ocxl_fn);
+
+     rc = scm_reserve_metadata(scm_data, lpc_mem);
+     if (rc)
+             return rc;
+
+     scm_data->bus_desc.attr_groups = scm_pmem_attribute_groups;
+     scm_data->bus_desc.provider_name = "scm";
+     scm_data->bus_desc.ndctl = scm_ndctl;
+     scm_data->bus_desc.module = THIS_MODULE;
+
+     scm_data->nvdimm_bus = nvdimm_bus_register(&scm_data->dev,
+                            &scm_data->bus_desc);
+     if (!scm_data->nvdimm_bus)
+             return -EINVAL;
+
+     scm_data->scm_res.start = (u64)lpc_mem->start + SCM_LABEL_AREA_SIZE;
+     scm_data->scm_res.end = (u64)lpc_mem->start + config->lpc_mem_size - 1;
+     scm_data->scm_res.name = "SCM persistent memory";
+
+     set_bit(ND_CMD_GET_CONFIG_SIZE, &nvdimm_cmd_mask);
+     set_bit(ND_CMD_GET_CONFIG_DATA, &nvdimm_cmd_mask);
+     set_bit(ND_CMD_SET_CONFIG_DATA, &nvdimm_cmd_mask);
+     set_bit(ND_CMD_SMART, &nvdimm_cmd_mask);
+
+     set_bit(NDD_ALIASING, &nvdimm_flags);
+
+     snprintf(serial, sizeof(serial), "%llx", fn_config->serial);
+     nd_mapping_desc.nvdimm = __nvdimm_create(scm_data->nvdimm_bus, scm_data,
+                              scm_dimm_attribute_groups,
+                              nvdimm_flags, nvdimm_cmd_mask,
+                              0, NULL, serial, &sec_ops);

nvdimm_create()?

quoted

+     if (!nd_mapping_desc.nvdimm)
+             return -ENOMEM;
+
+     if (nvdimm_bus_check_dimm_count(scm_data->nvdimm_bus, 1))
+             return -EINVAL;
+
+     nd_mapping_desc.start = scm_data->scm_res.start;
+     nd_mapping_desc.size = resource_size(&scm_data->scm_res);
+     nd_mapping_desc.position = 0;
+
+     scm_data->nd_set.cookie1 = fn_config->serial + 1; // allow for empty serial
+     scm_data->nd_set.cookie2 = fn_config->serial + 1;
+
+     target_node = of_node_to_nid(scm_data->pdev->dev.of_node);
+
+     memset(&region_desc, 0, sizeof(region_desc));
+     region_desc.res = &scm_data->scm_res;
+     region_desc.attr_groups = scm_pmem_region_attribute_groups;
+     region_desc.numa_node = NUMA_NO_NODE;
+     region_desc.target_node = target_node;
+     region_desc.num_mappings = 1;
+     region_desc.mapping = &nd_mapping_desc;
+     region_desc.nd_set = &scm_data->nd_set;
+
+     set_bit(ND_REGION_PAGEMAP, &region_desc.flags);
+     /*
+      * NB: libnvdimm copies the data from ndr_desc into it's own
+      * structures so passing a stack pointer is fine.
+      */
+     scm_data->nd_region = nvdimm_pmem_region_create(scm_data->nvdimm_bus,
+                           &region_desc);
+     if (!scm_data->nd_region)
+             return -EINVAL;
+
+     dev_info(&scm_data->dev,
+              "Onlining %lluMB of persistent memory\n",
+              nd_mapping_desc.size / SZ_1M);
+
+     return 0;
+}
+

Would it be possible to split the driver such that we add features like
security ops in later patch? Can this patch be a baisc dirver that just get
the nvdimm initialized. Any attribute specific to ocxl can be exported
in follow up patches?

Yes, please. This diffstat:

8 files changed, 3141 insertions(+), 1 deletion(-)

...is too big for a single patch, and one sentence of changelog for
that diffstat is too small.

You might look at the early history of driver/nvdimm/
drivers/acpi/nfit* to get some ideas on how to break this up into
smaller pieces that just do one theme per patch.

Also, given the timeframe / proximity to the v5.5 merge window opening
we're looking at the v5.6 merge window as the target.