Subject: Re: [PATCH v2 13/27] nvdimm/ocxl: Add support for Admin commands

From: Jonathan Cameron <[email-masked]>
Date: Mon, 3 Feb 2020 14:18:46 +0000

On Tue, 3 Dec 2019 14:46:41 +1100
Alastair D'Silva <[email-masked]> wrote:

> From: Alastair D'Silva <[email-masked]>
> 
> 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 <[email-masked]>

A few trivial bits inline.

Jonathan

> ---
>  drivers/nvdimm/ocxl/scm.c          |  67 +++++++++++++
>  drivers/nvdimm/ocxl/scm_internal.c | 152 +++++++++++++++++++++++++++++
>  drivers/nvdimm/ocxl/scm_internal.h |  62 ++++++++++++
>  3 files changed, 281 insertions(+)
> 
> diff --git a/drivers/nvdimm/ocxl/scm.c b/drivers/nvdimm/ocxl/scm.c
> index 8088f65c289e..1e175f3c3cf2 100644
> --- a/drivers/nvdimm/ocxl/scm.c
> +++ b/drivers/nvdimm/ocxl/scm.c
> @@ -267,6 +267,58 @@ static int scm_register_lpc_mem(struct scm_data *scm_data)
>  	return 0;
>  }
>  
> +/**
> + * scm_extract_command_metadata() - Extract command data from MMIO & save it for further use
> + * @scm_data: a pointer to the SCM device data
> + * @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 scm_extract_command_metadata(struct scm_data *scm_data, u32 offset,
> +					struct command_metadata *command_metadata)
> +{
> +	int rc;
> +	u64 tmp;
> +
> +	rc = ocxl_global_mmio_read64(scm_data->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(scm_data->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;
> +}
> +
> +/**
> + * scm_setup_command_metadata() - Set up the command metadata
> + * @scm_data: a pointer to the SCM device data
> + */
> +static int scm_setup_command_metadata(struct scm_data *scm_data)
> +{
> +	int rc;
> +
> +	mutex_init(&scm_data->admin_command.lock);
> +
> +	rc = scm_extract_command_metadata(scm_data, GLOBAL_MMIO_ACMA_CREQO,
> +					  &scm_data->admin_command);
> +	if (rc)
> +		return rc;

Unless you are adding to this later in the series.

	return scm_extract_command_metadata(scm_data,...)

> +
> +	return 0;
> +}
> +
>  /**
>   * scm_is_usable() - Is a controller usable?
>   * @scm_data: a pointer to the SCM device data
> @@ -276,6 +328,8 @@ static bool scm_is_usable(const struct scm_data *scm_data)
>  {
>  	u64 chi = 0;
>  	int rc = scm_chi(scm_data, &chi);
> +	if (rc)
> +		return false;
>  
>  	if (!(chi & GLOBAL_MMIO_CHI_CRDY)) {
>  		dev_err(&scm_data->dev, "SCM controller is not ready.\n");
> @@ -502,6 +556,14 @@ static int scm_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>  	}
>  	scm_data->pdev = pdev;
>  
> +	scm_data->timeouts[ADMIN_COMMAND_ERRLOG] = 2000; // ms
> +	scm_data->timeouts[ADMIN_COMMAND_HEARTBEAT] = 100; // ms
> +	scm_data->timeouts[ADMIN_COMMAND_SMART] = 100; // ms
> +	scm_data->timeouts[ADMIN_COMMAND_CONTROLLER_DUMP] = 1000; // ms
> +	scm_data->timeouts[ADMIN_COMMAND_CONTROLLER_STATS] = 100; // ms
> +	scm_data->timeouts[ADMIN_COMMAND_SHUTDOWN] = 1000; // ms
> +	scm_data->timeouts[ADMIN_COMMAND_FW_UPDATE] = 16000; // ms
> +
>  	pci_set_drvdata(pdev, scm_data);
>  
>  	scm_data->ocxl_fn = ocxl_function_open(pdev);
> @@ -543,6 +605,11 @@ static int scm_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>  		goto err;
>  	}
>  
> +	if (scm_setup_command_metadata(scm_data)) {
> +		dev_err(&pdev->dev, "Could not read OCXL command matada\n");
> +		goto err;
> +	}
> +
>  	elapsed = 0;
>  	timeout = scm_data->readiness_timeout + scm_data->memory_available_timeout;
>  	while (!scm_is_usable(scm_data)) {
> diff --git a/drivers/nvdimm/ocxl/scm_internal.c b/drivers/nvdimm/ocxl/scm_internal.c
> index 72d3c0e7d846..7b11b56863fb 100644
> --- a/drivers/nvdimm/ocxl/scm_internal.c
> +++ b/drivers/nvdimm/ocxl/scm_internal.c
> @@ -17,3 +17,155 @@ int scm_chi(const struct scm_data *scm_data, u64 *chi)
>  
>  	return 0;
>  }
> +
> +static int scm_command_request(const struct scm_data *scm_data,
> +			       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(scm_data->ocxl_afu, cmd->request_offset,
> +				      OCXL_LITTLE_ENDIAN, val);
> +	if (rc)
> +		return rc;
> +
> +	for (i = 0x08; i <= 0x38; i += 0x08) {

perhaps use sizeof(u64) to explain where the 0x08s come from.
For the 0x38, might be worth a define.

> +		rc = ocxl_global_mmio_write64(scm_data->ocxl_afu,
> +					      cmd->request_offset + i,
> +					      OCXL_LITTLE_ENDIAN, 0);
> +		if (rc)
> +			return rc;
> +	}
> +
> +	return 0;
> +}
> +
> +int scm_admin_command_request(struct scm_data *scm_data, u8 op_code)
> +{
> +	u64 val;
> +	int rc = ocxl_global_mmio_read64(scm_data->ocxl_afu, GLOBAL_MMIO_CHI,
> +					 OCXL_LITTLE_ENDIAN, &val);
> +	if (rc)
> +		return rc;
> +
> +	return scm_command_request(scm_data, &scm_data->admin_command, op_code);
> +}
> +
> +static int scm_command_response(const struct scm_data *scm_data,
> +			 const struct command_metadata *cmd)
> +{
> +	u64 val;
> +	u16 id;
> +	u8 status;
> +	int rc = ocxl_global_mmio_read64(scm_data->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(&scm_data->dev,
> +			 "Expected response for command %d, but received response for command %d instead.\n",
> +			 cmd->id, id);
> +	}
> +
> +	return status;
> +}
> +
> +int scm_admin_response(const struct scm_data *scm_data)
> +{
> +	return scm_command_response(scm_data, &scm_data->admin_command);
> +}
> +
> +
> +int scm_admin_command_execute(const struct scm_data *scm_data)
> +{
> +	return ocxl_global_mmio_set64(scm_data->ocxl_afu, GLOBAL_MMIO_HCI,
> +				      OCXL_LITTLE_ENDIAN, GLOBAL_MMIO_HCI_ACRW);
> +}
> +
> +static bool scm_admin_command_complete(const struct scm_data *scm_data)
> +{
> +	u64 val = 0;
> +
> +	int rc = scm_chi(scm_data, &val);
> +
> +	WARN_ON(rc);
> +
> +	return (val & GLOBAL_MMIO_CHI_ACRA) != 0;
> +}
> +
> +int scm_admin_command_complete_timeout(const struct scm_data *scm_data,
> +				       int command)
> +{
> +	u32 timeout = scm_data->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 = SCM_DEFAULT_TIMEOUT / TIMEOUT_SLEEP_MILLIS;
> +
> +	while (timeout-- > 0) {
> +		if (scm_admin_command_complete(scm_data))
> +			return 0;
> +		msleep(TIMEOUT_SLEEP_MILLIS);
> +	}
> +
> +	if (scm_admin_command_complete(scm_data))
> +		return 0;
> +
> +	return -EBUSY;
> +}
> +
> +int scm_admin_response_handled(const struct scm_data *scm_data)
> +{
> +	return ocxl_global_mmio_set64(scm_data->ocxl_afu, GLOBAL_MMIO_CHIC,
> +				      OCXL_LITTLE_ENDIAN, GLOBAL_MMIO_CHI_ACRA);
> +}
> +
> +void scm_warn_status(const struct scm_data *scm_data, 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(&scm_data->dev, "%s: %s (%x)\n", message, text, status);
> +}
> diff --git a/drivers/nvdimm/ocxl/scm_internal.h b/drivers/nvdimm/ocxl/scm_internal.h
> index 584450f55e30..9bff684cd069 100644
> --- a/drivers/nvdimm/ocxl/scm_internal.h
> +++ b/drivers/nvdimm/ocxl/scm_internal.h
> @@ -6,6 +6,8 @@
>  #include <linux/libnvdimm.h>
>  #include <linux/mm.h>
>  
> +#define SCM_DEFAULT_TIMEOUT 100
> +
>  #define GLOBAL_MMIO_CHI		0x000
>  #define GLOBAL_MMIO_CHIC	0x008
>  #define GLOBAL_MMIO_CHIE	0x010
> @@ -80,6 +82,16 @@
>  
>  #define SCM_LABEL_AREA_SIZE	(1UL << PA_SECTION_SHIFT)
>  
> +struct command_metadata {
> +	u32 request_offset;
> +	u32 response_offset;
> +	u32 data_offset;
> +	u32 data_size;
> +	struct mutex lock;
> +	u16 id;
> +	u8 op_code;
> +};
> +
>  struct scm_function_0 {
>  	struct pci_dev *pdev;
>  	struct ocxl_fn *ocxl_fn;
> @@ -95,9 +107,11 @@ struct scm_data {
>  	struct ocxl_afu *ocxl_afu;
>  	struct ocxl_context *ocxl_context;
>  	void *metadata_addr;
> +	struct command_metadata admin_command;
>  	struct resource scm_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 +136,51 @@ struct scm_data {
>   * Returns 0 on success, negative on error
>   */
>  int scm_chi(const struct scm_data *scm_data, u64 *chi);
> +
> +/**
> + * scm_admin_command_request() - Issue an admin command request
> + * @scm_data: a pointer to the SCM device data
> + * @op_code: The op-code for the command
> + *
> + * Returns an identifier for the command, or negative on error
> + */
> +int scm_admin_command_request(struct scm_data *scm_data, u8 op_code);
> +
> +/**
> + * scm_admin_response() - Validate an admin response
> + * @scm_data: a pointer to the SCM device data
> + * Returns the status code of the command, or negative on error
> + */
> +int scm_admin_response(const struct scm_data *scm_data);
> +
> +/**
> + * scm_admin_command_execute() - Notify the controller to start processing a pending admin command
> + * @scm_data: a pointer to the SCM device data
> + * Returns 0 on success, negative on error
> + */
> +int scm_admin_command_execute(const struct scm_data *scm_data);
> +
> +/**
> + * scm_admin_command_complete_timeout() - Wait for an admin command to finish executing
> + * @scm_data: a pointer to the SCM device data
> + * @command: the admin command to wait for completion (determines the timeout)
> + * Returns 0 on success, -EBUSY on timeout
> + */
> +int scm_admin_command_complete_timeout(const struct scm_data *scm_data,
> +				       int command);
> +
> +/**
> + * scm_admin_response_handled() - Notify the controller that the admin response has been handled
> + * @scm_data: a pointer to the SCM device data
> + * Returns 0 on success, negative on failure
> + */
> +int scm_admin_response_handled(const struct scm_data *scm_data);
> +
> +/**
> + * scm_warn_status() - Emit a kernel warning showing a command status.
> + * @scm_data: a pointer to the SCM device data
> + * @message: A message to accompany the warning
> + * @status: The command status
> + */
> +void scm_warn_status(const struct scm_data *scm_data, const char *message,
> +		     u8 status);