[dpdk-dev] [PATCH v3 09/32] qede: serialize access to MFW mbox
Rasesh Mody
rasesh.mody at qlogic.com
Sat Oct 15 22:07:46 CEST 2016
From: Harish Patil <harish.patil at qlogic.com>
Add ecore_mcp_mb_lock() and ecore_mcp_mb_unlock() APIs to ensure
a single thread is accessing MFW mailbox.
Signed-off-by: Harish Patil <harish.patil at qlogic.com>
---
drivers/net/qede/base/ecore_mcp.c | 70 ++++++++++++++++++++++++++++++++++-----
drivers/net/qede/base/ecore_mcp.h | 4 +++
2 files changed, 66 insertions(+), 8 deletions(-)
diff --git a/drivers/net/qede/base/ecore_mcp.c b/drivers/net/qede/base/ecore_mcp.c
index 24211a3..12e1ec1 100644
--- a/drivers/net/qede/base/ecore_mcp.c
+++ b/drivers/net/qede/base/ecore_mcp.c
@@ -202,6 +202,51 @@ err:
return ECORE_NOMEM;
}
+/* Locks the MFW mailbox of a PF to ensure a single access.
+ * The lock is achieved in most cases by holding a spinlock, causing other
+ * threads to wait till a previous access is done.
+ * In some cases (currently when a [UN]LOAD_REQ commands are sent), the single
+ * access is achieved by setting a blocking flag, which will fail other
+ * competing contexts to send their mailboxes.
+ */
+static enum _ecore_status_t ecore_mcp_mb_lock(struct ecore_hwfn *p_hwfn,
+ u32 cmd)
+{
+ OSAL_SPIN_LOCK(&p_hwfn->mcp_info->lock);
+
+ /* The spinlock shouldn't be acquired when the mailbox command is
+ * [UN]LOAD_REQ, since the engine is locked by the MFW, and a parallel
+ * pending [UN]LOAD_REQ command of another PF together with a spinlock
+ * (i.e. interrupts are disabled) - can lead to a deadlock.
+ * It is assumed that for a single PF, no other mailbox commands can be
+ * sent from another context while sending LOAD_REQ, and that any
+ * parallel commands to UNLOAD_REQ can be cancelled.
+ */
+ if (cmd == DRV_MSG_CODE_LOAD_DONE || cmd == DRV_MSG_CODE_UNLOAD_DONE)
+ p_hwfn->mcp_info->block_mb_sending = false;
+
+ if (p_hwfn->mcp_info->block_mb_sending) {
+ DP_NOTICE(p_hwfn, false,
+ "Trying to send a MFW mailbox command [0x%x] in parallel to [UN]LOAD_REQ. Aborting.\n",
+ cmd);
+ OSAL_SPIN_UNLOCK(&p_hwfn->mcp_info->lock);
+ return ECORE_BUSY;
+ }
+
+ if (cmd == DRV_MSG_CODE_LOAD_REQ || cmd == DRV_MSG_CODE_UNLOAD_REQ) {
+ p_hwfn->mcp_info->block_mb_sending = true;
+ OSAL_SPIN_UNLOCK(&p_hwfn->mcp_info->lock);
+ }
+
+ return ECORE_SUCCESS;
+}
+
+static void ecore_mcp_mb_unlock(struct ecore_hwfn *p_hwfn, u32 cmd)
+{
+ if (cmd != DRV_MSG_CODE_LOAD_REQ && cmd != DRV_MSG_CODE_UNLOAD_REQ)
+ OSAL_SPIN_UNLOCK(&p_hwfn->mcp_info->lock);
+}
+
enum _ecore_status_t ecore_mcp_reset(struct ecore_hwfn *p_hwfn,
struct ecore_ptt *p_ptt)
{
@@ -214,8 +259,12 @@ enum _ecore_status_t ecore_mcp_reset(struct ecore_hwfn *p_hwfn,
if (CHIP_REV_IS_EMUL(p_hwfn->p_dev))
delay = EMUL_MCP_RESP_ITER_US;
#endif
-
- OSAL_SPIN_LOCK(&p_hwfn->mcp_info->lock);
+ /* Ensure that only a single thread is accessing the mailbox at a
+ * certain time.
+ */
+ rc = ecore_mcp_mb_lock(p_hwfn, DRV_MSG_CODE_MCP_RESET);
+ if (rc != ECORE_SUCCESS)
+ return rc;
/* Set drv command along with the updated sequence */
org_mcp_reset_seq = ecore_rd(p_hwfn, p_ptt, MISCS_REG_GENERIC_POR_0);
@@ -238,7 +287,7 @@ enum _ecore_status_t ecore_mcp_reset(struct ecore_hwfn *p_hwfn,
rc = ECORE_AGAIN;
}
- OSAL_SPIN_UNLOCK(&p_hwfn->mcp_info->lock);
+ ecore_mcp_mb_unlock(p_hwfn, DRV_MSG_CODE_MCP_RESET);
return rc;
}
@@ -327,14 +376,16 @@ ecore_mcp_cmd_and_union(struct ecore_hwfn *p_hwfn, struct ecore_ptt *p_ptt,
return ECORE_BUSY;
}
- /* Acquiring a spinlock is needed to ensure that only a single thread
- * is accessing the mailbox at a certain time.
- */
- OSAL_SPIN_LOCK(&p_hwfn->mcp_info->lock);
-
union_data_addr = p_hwfn->mcp_info->drv_mb_addr +
OFFSETOF(struct public_drv_mb, union_data);
+ /* Ensure that only a single thread is accessing the mailbox at a
+ * certain time.
+ */
+ rc = ecore_mcp_mb_lock(p_hwfn, p_mb_params->cmd);
+ if (rc != ECORE_SUCCESS)
+ return rc;
+
if (p_mb_params->p_data_src != OSAL_NULL)
ecore_memcpy_to(p_hwfn, p_ptt, union_data_addr,
p_mb_params->p_data_src,
@@ -348,6 +399,9 @@ ecore_mcp_cmd_and_union(struct ecore_hwfn *p_hwfn, struct ecore_ptt *p_ptt,
ecore_memcpy_from(p_hwfn, p_ptt, p_mb_params->p_data_dst,
union_data_addr,
sizeof(*p_mb_params->p_data_dst));
+
+ ecore_mcp_mb_unlock(p_hwfn, p_mb_params->cmd);
+
return rc;
}
diff --git a/drivers/net/qede/base/ecore_mcp.h b/drivers/net/qede/base/ecore_mcp.h
index 28a8f93..e055835 100644
--- a/drivers/net/qede/base/ecore_mcp.h
+++ b/drivers/net/qede/base/ecore_mcp.h
@@ -32,6 +32,10 @@
((_p_hwfn)->p_dev->num_ports_in_engines * 2))
struct ecore_mcp_info {
osal_spinlock_t lock; /* Spinlock used for accessing MCP mailbox */
+
+ /* Flag to indicate whether sending a MFW mailbox is forbidden */
+ bool block_mb_sending;
+
u32 public_base; /* Address of the MCP public area */
u32 drv_mb_addr; /* Address of the driver mailbox */
u32 mfw_mb_addr; /* Address of the MFW mailbox */
--
1.8.3.1
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