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SubjectRe: [PATCH v3 14/27] powerpc/powernv/pmem: Add support for Admin commands
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On 21/2/20 2:27 pm, Alastair D'Silva wrote:
> From: Alastair D'Silva <alastair@d-silva.org>
>
> This patch requests the metadata required to issue admin commands, as well
> as some helper functions to construct and check the completion of the
> commands.
>
> Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
> ---
> arch/powerpc/platforms/powernv/pmem/ocxl.c | 65 ++++++++
> .../platforms/powernv/pmem/ocxl_internal.c | 153 ++++++++++++++++++
> .../platforms/powernv/pmem/ocxl_internal.h | 61 +++++++
> 3 files changed, 279 insertions(+)
>
> diff --git a/arch/powerpc/platforms/powernv/pmem/ocxl.c b/arch/powerpc/platforms/powernv/pmem/ocxl.c
> index 431212c9f0cc..4e782d22605b 100644
> --- a/arch/powerpc/platforms/powernv/pmem/ocxl.c
> +++ b/arch/powerpc/platforms/powernv/pmem/ocxl.c
> @@ -216,6 +216,58 @@ static int register_lpc_mem(struct ocxlpmem *ocxlpmem)
> return 0;
> }
>
> +/**
> + * extract_command_metadata() - Extract command data from MMIO & save it for further use
> + * @ocxlpmem: the device metadata
> + * @offset: The base address of the command data structures (address of CREQO)
> + * @command_metadata: A pointer to the command metadata to populate
> + * Return: 0 on success, negative on failure
> + */
> +static int extract_command_metadata(struct ocxlpmem *ocxlpmem, u32 offset,
> + struct command_metadata *command_metadata)
> +{
> + int rc;
> + u64 tmp;
> +
> + rc = ocxl_global_mmio_read64(ocxlpmem->ocxl_afu, offset, OCXL_LITTLE_ENDIAN,
> + &tmp);
> + if (rc)
> + return rc;
> +
> + command_metadata->request_offset = tmp >> 32;
> + command_metadata->response_offset = tmp & 0xFFFFFFFF;
> +
> + rc = ocxl_global_mmio_read64(ocxlpmem->ocxl_afu, offset + 8, OCXL_LITTLE_ENDIAN,
> + &tmp);
> + if (rc)
> + return rc;
> +
> + command_metadata->data_offset = tmp >> 32;
> + command_metadata->data_size = tmp & 0xFFFFFFFF;
> +
> + command_metadata->id = 0;
> +
> + return 0;
> +}
> +
> +/**
> + * setup_command_metadata() - Set up the command metadata
> + * @ocxlpmem: the device metadata
> + */
> +static int setup_command_metadata(struct ocxlpmem *ocxlpmem)
> +{
> + int rc;
> +
> + mutex_init(&ocxlpmem->admin_command.lock);
> +
> + rc = extract_command_metadata(ocxlpmem, GLOBAL_MMIO_ACMA_CREQO,
> + &ocxlpmem->admin_command);
> + if (rc)
> + return rc;
> +
> + return 0;
> +}
> +
> /**
> * is_usable() - Is a controller usable?
> * @ocxlpmem: the device metadata
> @@ -456,6 +508,14 @@ static int probe(struct pci_dev *pdev, const struct pci_device_id *ent)
> }
> ocxlpmem->pdev = pdev;
>
> + ocxlpmem->timeouts[ADMIN_COMMAND_ERRLOG] = 2000; // ms
> + ocxlpmem->timeouts[ADMIN_COMMAND_HEARTBEAT] = 100; // ms
> + ocxlpmem->timeouts[ADMIN_COMMAND_SMART] = 100; // ms
> + ocxlpmem->timeouts[ADMIN_COMMAND_CONTROLLER_DUMP] = 1000; // ms
> + ocxlpmem->timeouts[ADMIN_COMMAND_CONTROLLER_STATS] = 100; // ms
> + ocxlpmem->timeouts[ADMIN_COMMAND_SHUTDOWN] = 1000; // ms
> + ocxlpmem->timeouts[ADMIN_COMMAND_FW_UPDATE] = 16000; // ms

Why are we keeping these timeouts in a per device struct? I can't see
anywhere where we change these values.

> +
> pci_set_drvdata(pdev, ocxlpmem);
>
> ocxlpmem->ocxl_fn = ocxl_function_open(pdev);
> @@ -501,6 +561,11 @@ static int probe(struct pci_dev *pdev, const struct pci_device_id *ent)
> goto err;
> }
>
> + if (setup_command_metadata(ocxlpmem)) {
> + dev_err(&pdev->dev, "Could not read OCXL command matada\n");

metadata

Also, "OCXL command metadata" is misleading, this is a pmem specific
thing, not an OpenCAPI thing, I would prefer just "command metadata".

> + goto err;
> + }
> +
> elapsed = 0;
> timeout = ocxlpmem->readiness_timeout + ocxlpmem->memory_available_timeout;
> while (!is_usable(ocxlpmem, false)) {
> diff --git a/arch/powerpc/platforms/powernv/pmem/ocxl_internal.c b/arch/powerpc/platforms/powernv/pmem/ocxl_internal.c
> index 617ca943b1b8..583f48023025 100644
> --- a/arch/powerpc/platforms/powernv/pmem/ocxl_internal.c
> +++ b/arch/powerpc/platforms/powernv/pmem/ocxl_internal.c
> @@ -17,3 +17,156 @@ int ocxlpmem_chi(const struct ocxlpmem *ocxlpmem, u64 *chi)
>
> return 0;
> }
> +
> +#define COMMAND_REQUEST_SIZE (8 * sizeof(u64))
> +static int scm_command_request(const struct ocxlpmem *ocxlpmem,
> + struct command_metadata *cmd, u8 op_code)
> +{
> + u64 val = op_code;
> + int rc;
> + u8 i;
> +
> + cmd->op_code = op_code;
> + cmd->id++;
> +
> + val |= ((u64)cmd->id) << 16;
> +
> + rc = ocxl_global_mmio_write64(ocxlpmem->ocxl_afu, cmd->request_offset,
> + OCXL_LITTLE_ENDIAN, val);
> + if (rc)
> + return rc;
> +
> + for (i = sizeof(u64); i < COMMAND_REQUEST_SIZE; i += sizeof(u64)) {
> + rc = ocxl_global_mmio_write64(ocxlpmem->ocxl_afu,
> + cmd->request_offset + i,
> + OCXL_LITTLE_ENDIAN, 0);
> + if (rc)
> + return rc;
> + }
> +
> + return 0;
> +}
> +
> +int admin_command_request(struct ocxlpmem *ocxlpmem, u8 op_code)
> +{
> + u64 val;
> + int rc = ocxl_global_mmio_read64(ocxlpmem->ocxl_afu, GLOBAL_MMIO_CHI,
> + OCXL_LITTLE_ENDIAN, &val);
> + if (rc)
> + return rc;

Ignoring the value here expected, you're just trying to verify that you
don't see an error on the read?

> +
> + return scm_command_request(ocxlpmem, &ocxlpmem->admin_command, op_code);
> +}
> +
> +static int command_response(const struct ocxlpmem *ocxlpmem,
> + const struct command_metadata *cmd)
> +{
> + u64 val;
> + u16 id;
> + u8 status;
> + int rc = ocxl_global_mmio_read64(ocxlpmem->ocxl_afu,
> + cmd->response_offset,
> + OCXL_LITTLE_ENDIAN, &val);
> + if (rc)
> + return rc;
> +
> + status = val & 0xff;
> + id = (val >> 16) & 0xffff;
> +
> + if (id != cmd->id) {
> + dev_warn(&ocxlpmem->dev,
> + "Expected response for command %d, but received response for command %d instead.\n",
> + cmd->id, id);

If this happens I imagine something's gone pretty wrong - this should
probably be a dev_err()? And perhaps we want to make sure we return an
error code rather than whatever status code we get from the MMIO?

> + }
> +
> + return status;
> +}
> +
> +int admin_response(const struct ocxlpmem *ocxlpmem)
> +{
> + return command_response(ocxlpmem, &ocxlpmem->admin_command);
> +}
> +
> +
> +int admin_command_execute(const struct ocxlpmem *ocxlpmem)
> +{
> + return ocxl_global_mmio_set64(ocxlpmem->ocxl_afu, GLOBAL_MMIO_HCI,
> + OCXL_LITTLE_ENDIAN, GLOBAL_MMIO_HCI_ACRW);
> +}
> +
> +static bool admin_command_complete(const struct ocxlpmem *ocxlpmem)
> +{
> + u64 val = 0;
> +
> + int rc = ocxlpmem_chi(ocxlpmem, &val);
> +
> + WARN_ON(rc);
> +
> + return (val & GLOBAL_MMIO_CHI_ACRA) != 0;
> +}
> +
> +int admin_command_complete_timeout(const struct ocxlpmem *ocxlpmem,
> + int command)
> +{
> + u32 timeout = ocxlpmem->timeouts[command];
> + // 32 is the next power of 2 greater than the 20ms minimum for msleep
> +#define TIMEOUT_SLEEP_MILLIS 32
> + timeout /= TIMEOUT_SLEEP_MILLIS;
> + if (!timeout)
> + timeout = DEFAULT_TIMEOUT / TIMEOUT_SLEEP_MILLIS;
> +
> + while (timeout-- > 0) {
> + if (admin_command_complete(ocxlpmem))
> + return 0;
> + msleep(TIMEOUT_SLEEP_MILLIS);
> + }

I think the more traditional way to implement timeouts is something more
like:

unsigned long timeout = jiffies + msecs_to_jiffies(<timeout period>);
do {
<check>
<sleep>
} while (time_before(jiffies, timeout));

> +
> + if (admin_command_complete(ocxlpmem))
> + return 0;
> +
> + return -EBUSY;
> +}
> +
> +int admin_response_handled(const struct ocxlpmem *ocxlpmem)
> +{
> + return ocxl_global_mmio_set64(ocxlpmem->ocxl_afu, GLOBAL_MMIO_CHIC,
> + OCXL_LITTLE_ENDIAN, GLOBAL_MMIO_CHI_ACRA);
> +}

This looks wrong? My reading of the spec is that you're meant to *clear*
ACRA upon completion of handing, this looks like it's setting ACRA to 1.

> +
> +void warn_status(const struct ocxlpmem *ocxlpmem, const char *message,
> + u8 status)
> +{
> + const char *text = "Unknown";
> +
> + switch (status) {
> + case STATUS_SUCCESS:
> + text = "Success";
> + break;
> +
> + case STATUS_MEM_UNAVAILABLE:
> + text = "Persistent memory unavailable";
> + break;
> +
> + case STATUS_BAD_OPCODE:
> + text = "Bad opcode";
> + break;
> +
> + case STATUS_BAD_REQUEST_PARM:
> + text = "Bad request parameter";
> + break;
> +
> + case STATUS_BAD_DATA_PARM:
> + text = "Bad data parameter";
> + break;
> +
> + case STATUS_DEBUG_BLOCKED:
> + text = "Debug action blocked";
> + break;
> +
> + case STATUS_FAIL:
> + text = "Failed";
> + break;
> + }
> +
> + dev_warn(&ocxlpmem->dev, "%s: %s (%x)\n", message, text, status);
> +}
> diff --git a/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h b/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h
> index ba0301533d00..2fef68c71271 100644
> --- a/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h
> +++ b/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h
> @@ -7,6 +7,7 @@
> #include <linux/mm.h>
>
> #define LABEL_AREA_SIZE (1UL << PA_SECTION_SHIFT)
> +#define DEFAULT_TIMEOUT 100
>
> #define GLOBAL_MMIO_CHI 0x000
> #define GLOBAL_MMIO_CHIC 0x008
> @@ -80,6 +81,16 @@
> #define STATUS_FW_ARG_INVALID 0x51
> #define STATUS_FW_INVALID 0x52
>
> +struct command_metadata {
> + u32 request_offset;
> + u32 response_offset;
> + u32 data_offset;
> + u32 data_size;
> + struct mutex lock;
> + u16 id;
> + u8 op_code;
> +};
> +
> struct ocxlpmem_function0 {
> struct pci_dev *pdev;
> struct ocxl_fn *ocxl_fn;
> @@ -95,9 +106,11 @@ struct ocxlpmem {
> struct ocxl_afu *ocxl_afu;
> struct ocxl_context *ocxl_context;
> void *metadata_addr;
> + struct command_metadata admin_command;
> struct resource pmem_res;
> struct nd_region *nd_region;
> char fw_version[8+1];
> + u32 timeouts[ADMIN_COMMAND_MAX+1];
>
> u32 max_controller_dump_size;
> u16 scm_revision; // major/minor
> @@ -122,3 +135,51 @@ struct ocxlpmem {
> * Returns 0 on success, negative on error
> */
> int ocxlpmem_chi(const struct ocxlpmem *ocxlpmem, u64 *chi);
> +
> +/**
> + * admin_command_request() - Issue an admin command request
> + * @ocxlpmem: the device metadata
> + * @op_code: The op-code for the command
> + *
> + * Returns an identifier for the command, or negative on error
> + */
> +int admin_command_request(struct ocxlpmem *ocxlpmem, u8 op_code);
> +
> +/**
> + * admin_response() - Validate an admin response
> + * @ocxlpmem: the device metadata
> + * Returns the status code of the command, or negative on error
> + */
> +int admin_response(const struct ocxlpmem *ocxlpmem);
> +
> +/**
> + * admin_command_execute() - Notify the controller to start processing a pending admin command
> + * @ocxlpmem: the device metadata
> + * Returns 0 on success, negative on error
> + */
> +int admin_command_execute(const struct ocxlpmem *ocxlpmem);
> +
> +/**
> + * admin_command_complete_timeout() - Wait for an admin command to finish executing
> + * @ocxlpmem: the device metadata
> + * @command: the admin command to wait for completion (determines the timeout)
> + * Returns 0 on success, -EBUSY on timeout
> + */
> +int admin_command_complete_timeout(const struct ocxlpmem *ocxlpmem,
> + int command);
> +
> +/**
> + * admin_response_handled() - Notify the controller that the admin response has been handled
> + * @ocxlpmem: the device metadata
> + * Returns 0 on success, negative on failure
> + */
> +int admin_response_handled(const struct ocxlpmem *ocxlpmem);
> +
> +/**
> + * warn_status() - Emit a kernel warning showing a command status.
> + * @ocxlpmem: the device metadata
> + * @message: A message to accompany the warning
> + * @status: The command status
> + */
> +void warn_status(const struct ocxlpmem *ocxlpmem, const char *message,
> + u8 status);
>

--
Andrew Donnellan OzLabs, ADL Canberra
ajd@linux.ibm.com IBM Australia Limited
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