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: 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>

diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
index e14bcd7..c142532 100644 (file)
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h
@@ -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__ */

diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
index 8077d90..e2f2767 100644 (file)
--- a/drivers/cxl/pci.c
+++ b/drivers/cxl/pci.c
@@ -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);