Commit b64955a9 authored by Dan Williams's avatar Dan Williams
Browse files

cxl/mbox: Introduce the mbox_send operation 



In preparation for implementing a unit test backend transport for ioctl
operations, and making the mailbox available to the cxl/pmem
infrastructure, move the existing PCI specific portion of mailbox handling
to an "mbox_send" operation.

With this split all the PCI-specific transport details are comprehended
by a single operation and the rest of the mailbox infrastructure is
'struct cxl_mem' and 'struct cxl_memdev' generic.

Acked-by: default avatarBen Widawsky <ben.widawsky@intel.com>
Reviewed-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: default avatarBen Widawsky <ben.widawsky@intel.com>
Link: https://lore.kernel.org/r/163116434098.2460985.9004760022659400540.stgit@dwillia2-desk3.amr.corp.intel.com


Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 13e7749d

drivers/cxl/cxlmem.h

+42 −0
Original line number Diff line number Diff line
@@ -66,6 +66,45 @@ struct cxl_memdev * 
devm_cxl_add_memdev(struct cxl_mem *cxlm,

		    const struct cdevm_file_operations *cdevm_fops);



/**

 * struct cxl_mbox_cmd - A command to be submitted to hardware.

 * @opcode: (input) The command set and command submitted to hardware.

 * @payload_in: (input) Pointer to the input payload.

 * @payload_out: (output) Pointer to the output payload. Must be allocated by

 *		 the caller.

 * @size_in: (input) Number of bytes to load from @payload_in.

 * @size_out: (input) Max number of bytes loaded into @payload_out.

 *            (output) Number of bytes generated by the device. For fixed size

 *            outputs commands this is always expected to be deterministic. For

 *            variable sized output commands, it tells the exact number of bytes

 *            written.

 * @return_code: (output) Error code returned from hardware.

 *

 * This is the primary mechanism used to send commands to the hardware.

 * All the fields except @payload_* correspond exactly to the fields described in

 * Command Register section of the CXL 2.0 8.2.8.4.5. @payload_in and

 * @payload_out are written to, and read from the Command Payload Registers

 * defined in CXL 2.0 8.2.8.4.8.

 */

struct cxl_mbox_cmd {

	u16 opcode;

	void *payload_in;

	void *payload_out;

	size_t size_in;

	size_t size_out;

	u16 return_code;

#define CXL_MBOX_SUCCESS 0

};



/*

 * CXL 2.0 - Memory capacity multiplier

 * See Section 8.2.9.5

 *

 * Volatile, Persistent, and Partition capacities are specified to be in

 * multiples of 256MB - define a multiplier to convert to/from bytes.

 */

#define CXL_CAPACITY_MULTIPLIER SZ_256M



/**

 * struct cxl_mem - A CXL memory device

 * @dev: The device associated with this CXL device.
@@ -88,6 +127,7 @@ devm_cxl_add_memdev(struct cxl_mem *cxlm, 
 * @active_persistent_bytes: sum of hard + soft persistent

 * @next_volatile_bytes: volatile capacity change pending device reset

 * @next_persistent_bytes: persistent capacity change pending device reset

 * @mbox_send: @dev specific transport for transmitting mailbox commands

 *

 * See section 8.2.9.5.2 Capacity Configuration and Label Storage for

 * details on capacity parameters.
@@ -115,5 +155,7 @@ struct cxl_mem { 
	u64 active_persistent_bytes;

	u64 next_volatile_bytes;

	u64 next_persistent_bytes;



	int (*mbox_send)(struct cxl_mem *cxlm, struct cxl_mbox_cmd *cmd);

};

#endif /* __CXL_MEM_H__ */

drivers/cxl/pci.c

+21 −55
Original line number Diff line number Diff line
@@ -64,45 +64,6 @@ enum opcode { 
	CXL_MBOX_OP_MAX			= 0x10000

};



/*

 * CXL 2.0 - Memory capacity multiplier

 * See Section 8.2.9.5

 *

 * Volatile, Persistent, and Partition capacities are specified to be in

 * multiples of 256MB - define a multiplier to convert to/from bytes.

 */

#define CXL_CAPACITY_MULTIPLIER SZ_256M



/**

 * struct mbox_cmd - A command to be submitted to hardware.

 * @opcode: (input) The command set and command submitted to hardware.

 * @payload_in: (input) Pointer to the input payload.

 * @payload_out: (output) Pointer to the output payload. Must be allocated by

 *		 the caller.

 * @size_in: (input) Number of bytes to load from @payload_in.

 * @size_out: (input) Max number of bytes loaded into @payload_out.

 *            (output) Number of bytes generated by the device. For fixed size

 *            outputs commands this is always expected to be deterministic. For

 *            variable sized output commands, it tells the exact number of bytes

 *            written.

 * @return_code: (output) Error code returned from hardware.

 *

 * This is the primary mechanism used to send commands to the hardware.

 * All the fields except @payload_* correspond exactly to the fields described in

 * Command Register section of the CXL 2.0 8.2.8.4.5. @payload_in and

 * @payload_out are written to, and read from the Command Payload Registers

 * defined in CXL 2.0 8.2.8.4.8.

 */

struct mbox_cmd {

	u16 opcode;

	void *payload_in;

	void *payload_out;

	size_t size_in;

	size_t size_out;

	u16 return_code;

#define CXL_MBOX_SUCCESS 0

};



static DECLARE_RWSEM(cxl_memdev_rwsem);

static struct dentry *cxl_debugfs;

static bool cxl_raw_allow_all;
@@ -266,7 +227,7 @@ static bool cxl_is_security_command(u16 opcode) 
}



static void cxl_mem_mbox_timeout(struct cxl_mem *cxlm,

				 struct mbox_cmd *mbox_cmd)

				 struct cxl_mbox_cmd *mbox_cmd)

{

	struct device *dev = cxlm->dev;
@@ -297,7 +258,7 @@ static void cxl_mem_mbox_timeout(struct cxl_mem *cxlm, 
 * mailbox.

 */

static int __cxl_mem_mbox_send_cmd(struct cxl_mem *cxlm,

				   struct mbox_cmd *mbox_cmd)

				   struct cxl_mbox_cmd *mbox_cmd)

{

	void __iomem *payload = cxlm->regs.mbox + CXLDEV_MBOX_PAYLOAD_OFFSET;

	struct device *dev = cxlm->dev;
@@ -472,6 +433,20 @@ static void cxl_mem_mbox_put(struct cxl_mem *cxlm) 
	mutex_unlock(&cxlm->mbox_mutex);

}



static int cxl_pci_mbox_send(struct cxl_mem *cxlm, struct cxl_mbox_cmd *cmd)

{

	int rc;



	rc = cxl_mem_mbox_get(cxlm);

	if (rc)

		return rc;



	rc = __cxl_mem_mbox_send_cmd(cxlm, cmd);

	cxl_mem_mbox_put(cxlm);



	return rc;

}



/**

 * handle_mailbox_cmd_from_user() - Dispatch a mailbox command for userspace.

 * @cxlm: The CXL memory device to communicate with.
@@ -503,7 +478,7 @@ static int handle_mailbox_cmd_from_user(struct cxl_mem *cxlm, 
					s32 *size_out, u32 *retval)

{

	struct device *dev = cxlm->dev;

	struct mbox_cmd mbox_cmd = {

	struct cxl_mbox_cmd mbox_cmd = {

		.opcode = cmd->opcode,

		.size_in = cmd->info.size_in,

		.size_out = cmd->info.size_out,
@@ -525,10 +500,6 @@ static int handle_mailbox_cmd_from_user(struct cxl_mem *cxlm, 
		}

	}



	rc = cxl_mem_mbox_get(cxlm);

	if (rc)

		goto out;



	dev_dbg(dev,

		"Submitting %s command for user\n"

		"\topcode: %x\n"
@@ -539,8 +510,7 @@ static int handle_mailbox_cmd_from_user(struct cxl_mem *cxlm, 
	dev_WARN_ONCE(dev, cmd->info.id == CXL_MEM_COMMAND_ID_RAW,

		      "raw command path used\n");



	rc = __cxl_mem_mbox_send_cmd(cxlm, &mbox_cmd);

	cxl_mem_mbox_put(cxlm);

	rc = cxlm->mbox_send(cxlm, &mbox_cmd);

	if (rc)

		goto out;
@@ -874,7 +844,7 @@ static int cxl_mem_mbox_send_cmd(struct cxl_mem *cxlm, u16 opcode, 
				 void *out, size_t out_size)

{

	const struct cxl_mem_command *cmd = cxl_mem_find_command(opcode);

	struct mbox_cmd mbox_cmd = {

	struct cxl_mbox_cmd mbox_cmd = {

		.opcode = opcode,

		.payload_in = in,

		.size_in = in_size,
@@ -886,12 +856,7 @@ static int cxl_mem_mbox_send_cmd(struct cxl_mem *cxlm, u16 opcode, 
	if (out_size > cxlm->payload_size)

		return -E2BIG;



	rc = cxl_mem_mbox_get(cxlm);

	if (rc)

		return rc;



	rc = __cxl_mem_mbox_send_cmd(cxlm, &mbox_cmd);

	cxl_mem_mbox_put(cxlm);

	rc = cxlm->mbox_send(cxlm, &mbox_cmd);

	if (rc)

		return rc;
@@ -913,6 +878,7 @@ static int cxl_mem_setup_mailbox(struct cxl_mem *cxlm) 
{

	const int cap = readl(cxlm->regs.mbox + CXLDEV_MBOX_CAPS_OFFSET);



	cxlm->mbox_send = cxl_pci_mbox_send;

	cxlm->payload_size =

		1 << FIELD_GET(CXLDEV_MBOX_CAP_PAYLOAD_SIZE_MASK, cap);