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Date: Tue, 14 Apr 2015 18:00:45 +0530
From: Hariprasad Shenai <hariprasad@...lsio.com>
To: netdev@...r.kernel.org
Cc: davem@...emloft.net, leedom@...lsio.com, nirranjan@...lsio.com,
Hariprasad Shenai <hariprasad@...lsio.com>
Subject: [PATCH net] cxgb4vf: Implement mailbox access locking and list management
Implement queue mechanism using list for avoiding concurrent access to mailbox
and provide fair access to mailbox for all commands being executed
Signed-off-by: Hariprasad Shenai <hariprasad@...lsio.com>
---
drivers/net/ethernet/chelsio/cxgb4vf/adapter.h | 8 ++++
.../net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c | 3 ++
drivers/net/ethernet/chelsio/cxgb4vf/t4vf_hw.c | 56 +++++++++++++++++++++-
3 files changed, 66 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/chelsio/cxgb4vf/adapter.h b/drivers/net/ethernet/chelsio/cxgb4vf/adapter.h
index 6049f70..15d9440 100644
--- a/drivers/net/ethernet/chelsio/cxgb4vf/adapter.h
+++ b/drivers/net/ethernet/chelsio/cxgb4vf/adapter.h
@@ -348,6 +348,10 @@ struct sge {
#define for_each_ethrxq(sge, iter) \
for (iter = 0; iter < (sge)->ethqsets; iter++)
+struct mbox_list {
+ struct list_head list;
+};
+
/*
* Per-"adapter" (Virtual Function) information.
*/
@@ -381,6 +385,10 @@ struct adapter {
/* various locks */
spinlock_t stats_lock;
+
+ /* support for single-threading access to adapter mailbox registers */
+ spinlock_t mbox_lock;
+ struct mbox_list mlist;
};
enum { /* adapter flags */
diff --git a/drivers/net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c b/drivers/net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c
index 122e296..6ca1540 100644
--- a/drivers/net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c
+++ b/drivers/net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c
@@ -2680,6 +2680,9 @@ static int cxgb4vf_pci_probe(struct pci_dev *pdev,
*/
spin_lock_init(&adapter->stats_lock);
+ spin_lock_init(&adapter->mbox_lock);
+ INIT_LIST_HEAD(&adapter->mlist.list);
+
/*
* Map our I/O registers in BAR0.
*/
diff --git a/drivers/net/ethernet/chelsio/cxgb4vf/t4vf_hw.c b/drivers/net/ethernet/chelsio/cxgb4vf/t4vf_hw.c
index 280b4a2..fb4c135 100644
--- a/drivers/net/ethernet/chelsio/cxgb4vf/t4vf_hw.c
+++ b/drivers/net/ethernet/chelsio/cxgb4vf/t4vf_hw.c
@@ -125,6 +125,7 @@ int t4vf_wr_mbox_core(struct adapter *adapter, const void *cmd, int size,
const __be64 *p;
u32 mbox_data = T4VF_MBDATA_BASE_ADDR;
u32 mbox_ctl = T4VF_CIM_BASE_ADDR + CIM_VF_EXT_MAILBOX_CTRL;
+ struct mbox_list entry;
/*
* Commands must be multiples of 16 bytes in length and may not be
@@ -134,6 +135,49 @@ int t4vf_wr_mbox_core(struct adapter *adapter, const void *cmd, int size,
size > NUM_CIM_VF_MAILBOX_DATA_INSTANCES * 4)
return -EINVAL;
+ /* Queue ourselves onto the mailbox access list. When our entry is at
+ * the front of the list, we have rights to access the mailbox. So we
+ * wait [for a while] till we're at the front [or bail out with an
+ * EBUSY] ...
+ */
+ spin_lock(&adapter->mbox_lock);
+ list_add_tail(&entry.list, &adapter->mlist.list);
+ spin_unlock(&adapter->mbox_lock);
+
+ delay_idx = 0;
+ ms = delay[0];
+
+ for (i = 0; ; i += ms) {
+ /* If we've waited too long, return a busy indication. This
+ * really ought to be based on our initial position in the
+ * mailbox access list but this is a start. We very rarely
+ * contend on access to the mailbox ...
+ */
+ if (i > 4 * FW_CMD_MAX_TIMEOUT) {
+ spin_lock(&adapter->mbox_lock);
+ list_del(&entry.list);
+ spin_unlock(&adapter->mbox_lock);
+ return -EBUSY;
+ }
+
+ /* If we're at the head, break out and start the mailbox
+ * protocol.
+ */
+ if (list_first_entry(&adapter->mlist.list,
+ struct mbox_list, list) == &entry)
+ break;
+
+ /* Delay for a bit before checking again ...*/
+ if (sleep_ok) {
+ ms = delay[delay_idx]; /* last element may repeat */
+ if (delay_idx < ARRAY_SIZE(delay) - 1)
+ delay_idx++;
+ msleep(ms);
+ } else {
+ mdelay(ms);
+ }
+ }
+
/*
* Loop trying to get ownership of the mailbox. Return an error
* if we can't gain ownership.
@@ -141,8 +185,12 @@ int t4vf_wr_mbox_core(struct adapter *adapter, const void *cmd, int size,
v = MBOWNER_G(t4_read_reg(adapter, mbox_ctl));
for (i = 0; v == MBOX_OWNER_NONE && i < 3; i++)
v = MBOWNER_G(t4_read_reg(adapter, mbox_ctl));
- if (v != MBOX_OWNER_DRV)
+ if (v != MBOX_OWNER_DRV) {
+ spin_lock(&adapter->mbox_lock);
+ list_del(&entry.list);
+ spin_unlock(&adapter->mbox_lock);
return v == MBOX_OWNER_FW ? -EBUSY : -ETIMEDOUT;
+ }
/*
* Write the command array into the Mailbox Data register array and
@@ -218,6 +266,9 @@ int t4vf_wr_mbox_core(struct adapter *adapter, const void *cmd, int size,
}
t4_write_reg(adapter, mbox_ctl,
MBOWNER_V(MBOX_OWNER_NONE));
+ spin_lock(&adapter->mbox_lock);
+ list_del(&entry.list);
+ spin_unlock(&adapter->mbox_lock);
return -FW_CMD_RETVAL_G(v);
}
}
@@ -226,6 +277,9 @@ int t4vf_wr_mbox_core(struct adapter *adapter, const void *cmd, int size,
* We timed out. Return the error ...
*/
dump_mbox(adapter, "FW Timeout", mbox_data);
+ spin_lock(&adapter->mbox_lock);
+ list_del(&entry.list);
+ spin_unlock(&adapter->mbox_lock);
return -ETIMEDOUT;
}
--
2.3.4
--
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