[RFC PATCH v2 3/4] cxl: Abort background operation in case of timeout

[Ravis OpenSrc <Ravis.OpenSrc@micron.com>]

Adding support for aborting timed out background operations

CXL r3.1 8.2.9.1.5 Request Abort Background Operation.

If the status of a mailbox command is identified as timedout,
an abort background operation request is sent to the device.

Link:
https://lore.kernel.org/linux-cxl/66035c2e8ba17_770232948b@dwillia2-xfh.jf.intel.com.notmuch/

Suggested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Ajay Joshi <ajay.opensrc@micron.com>
Signed-off-by: Ravi Shankar <ravis.opensrc@micron.com>
---
 drivers/cxl/cxlmem.h |  1 +
 drivers/cxl/pci.c    | 11 +++++++++++
 2 files changed, 12 insertions(+)

diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
index d8c0894797ac..808fb8712145 100644
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h
@@ -516,6 +516,7 @@ to_cxl_memdev_state(struct cxl_dev_state *cxlds)
 enum cxl_opcode {
         CXL_MBOX_OP_INVALID             = 0x0000,
         CXL_MBOX_OP_RAW                 = CXL_MBOX_OP_INVALID,
+       CXL_MBOX_OP_REQ_ABRT_BACKGROUND_OPERATION    = 0x0005,
         CXL_MBOX_OP_GET_EVENT_RECORD    = 0x0100,
         CXL_MBOX_OP_CLEAR_EVENT_RECORD  = 0x0101,
         CXL_MBOX_OP_GET_EVT_INT_POLICY  = 0x0102,
diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
index d5d6142f6aa3..95c1f329bca2 100644
--- a/drivers/cxl/pci.c
+++ b/drivers/cxl/pci.c
@@ -394,6 +394,17 @@ static int cxl_pci_mbox_send(struct cxl_mailbox *cxl_mbox,
 
         mutex_lock_io(&cxl_mbox->mbox_mutex);
         rc = __cxl_pci_mbox_send_cmd(cxl_mbox, cmd);
+       if (rc == -ETIMEDOUT &&
+               cmd->return_code == CXL_MBOX_CMD_RC_BACKGROUND) {
+               struct cxl_mbox_cmd abort_cmd = {
+                       .opcode = CXL_MBOX_OP_REQ_ABRT_BACKGROUND_OPERATION
+               };
+
+               rc = __cxl_pci_mbox_send_cmd(cxl_mbox, &abort_cmd);
+               if (!rc)
+                       rc = -ECANCELED;
+       }
+
         mutex_unlock(&cxl_mbox->mbox_mutex);
 
         return rc;
-- 
2.43.0