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cxl/mbox: Introduce the mbox_send operation
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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: Ben Widawsky <ben.widawsky@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Ben Widawsky <ben.widawsky@intel.com>
Link: https://lore.kernel.org/r/163116434098.2460985.9004760022659400540.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
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Dan Williams committed Sep 21, 2021
1 parent 13e7749 commit b64955a
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Showing 2 changed files with 63 additions and 55 deletions.
42 changes: 42 additions & 0 deletions drivers/cxl/cxlmem.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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.
Expand All @@ -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.
Expand Down Expand Up @@ -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__ */
76 changes: 21 additions & 55 deletions drivers/cxl/pci.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down Expand Up @@ -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;

Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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.
Expand Down Expand Up @@ -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,
Expand All @@ -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"
Expand All @@ -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;

Expand Down Expand Up @@ -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,
Expand All @@ -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;

Expand All @@ -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);

Expand Down

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