net: ipa: signal when tag transfer completes

There are times, such as when the modem crashes, when we issue
commands to clear the IPA hardware pipeline.  These commands include
a data transfer command that delivers a small packet directly to the
default (AP<-LAN RX) endpoint.

The places that do this wait for the transactions that contain these
commands to complete, but the pipeline can't be assumed clear until
the sent packet has been *received*.

The small transfer will be delivered with a status structure, and
that status will indicate its tag is valid.  This is the only place
we send a tagged packet, so we use the tag to determine when the
pipeline clear packet has arrived.

Add a completion to the IPA structure to to be used to signal
the receipt of a pipeline clear packet.  Create a new function
ipa_cmd_pipeline_clear_wait() that will wait for that completion.

Reinitialize the completion whenever pipeline clear commands are
added to a transaction.  Extend ipa_endpoint_status_tag() to check
whether a packet whose status contains a valid tag was sent from the
AP->command TX endpoint, and if so, signal the new IPA completion.

Have all callers of ipa_cmd_pipeline_clear_add() wait for the
pipeline clear indication after the transaction that clears the
pipeline has completed.

Signed-off-by: Alex Elder <elder@linaro.org>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ipa/ipa.h b/drivers/net/ipa/ipa.h
index c6c6a7f6909c184744b332d9699aa280fd150015..8020776313716897b7de7f68456a1632074d3afe 100644 (file)
--- a/drivers/net/ipa/ipa.h
+++ b/drivers/net/ipa/ipa.h
@@ -43,6 +43,7 @@ enum ipa_flag {
  * @flags:             Boolean state flags
  * @version:           IPA hardware version
  * @pdev:              Platform device
+ * @completion:                Used to signal pipeline clear transfer complete
  * @smp2p:             SMP2P information
  * @clock:             IPA clocking information
  * @table_addr:                DMA address of filter/route table content
@@ -82,6 +83,7 @@ struct ipa {
        DECLARE_BITMAP(flags, IPA_FLAG_COUNT);
        enum ipa_version version;
        struct platform_device *pdev;
+       struct completion completion;
        struct notifier_block nb;
        void *notifier;
        struct ipa_smp2p *smp2p;

diff --git a/drivers/net/ipa/ipa_cmd.c b/drivers/net/ipa/ipa_cmd.c
index 27630244512d82e466110f943933e7893dd414ee..7df0072bddccecb96f398c90cf4d1327d0adf4e3 100644 (file)
--- a/drivers/net/ipa/ipa_cmd.c
+++ b/drivers/net/ipa/ipa_cmd.c
@@ -573,6 +573,9 @@ void ipa_cmd_pipeline_clear_add(struct gsi_trans *trans)
        struct ipa *ipa = container_of(trans->gsi, struct ipa, gsi);
        struct ipa_endpoint *endpoint;
 
+       /* This will complete when the transfer is received */
+       reinit_completion(&ipa->completion);
+
        /* Issue a no-op register write command (mask 0 means no write) */
        ipa_cmd_register_write_add(trans, 0, 0, 0, true);
 
@@ -596,6 +599,11 @@ u32 ipa_cmd_pipeline_clear_count(void)
        return 4;
 }
 
+void ipa_cmd_pipeline_clear_wait(struct ipa *ipa)
+{
+       wait_for_completion(&ipa->completion);
+}
+
 void ipa_cmd_pipeline_clear(struct ipa *ipa)
 {
        u32 count = ipa_cmd_pipeline_clear_count();
@@ -605,6 +613,7 @@ void ipa_cmd_pipeline_clear(struct ipa *ipa)
        if (trans) {
                ipa_cmd_pipeline_clear_add(trans);
                gsi_trans_commit_wait(trans);
+               ipa_cmd_pipeline_clear_wait(ipa);
        } else {
                dev_err(&ipa->pdev->dev,
                        "error allocating %u entry tag transaction\n", count);

diff --git a/drivers/net/ipa/ipa_cmd.h b/drivers/net/ipa/ipa_cmd.h
index a41a58cc2c5acb2f1c11fc074b9adab27c427315..6dd3d35cf315d45300b2677d84740768f05e4b56 100644 (file)
--- a/drivers/net/ipa/ipa_cmd.h
+++ b/drivers/net/ipa/ipa_cmd.h
@@ -170,8 +170,15 @@ void ipa_cmd_pipeline_clear_add(struct gsi_trans *trans);
  */
 u32 ipa_cmd_pipeline_clear_count(void);
 
+/**
+ * ipa_cmd_pipeline_clear_wait() - Wait pipeline clear to complete
+ * @ipa:       - IPA pointer
+ */
+void ipa_cmd_pipeline_clear_wait(struct ipa *ipa);
+
 /**
  * ipa_cmd_pipeline_clear() - Clear the hardware pipeline
+ * @ipa:       - IPA pointer
  */
 void ipa_cmd_pipeline_clear(struct ipa *ipa);
 

diff --git a/drivers/net/ipa/ipa_endpoint.c b/drivers/net/ipa/ipa_endpoint.c
index 68970a3baa47acbc6ba5d97a5fec5446c49ea509..8313220d41e7046b806b99bc23e16b8e20248522 100644 (file)
--- a/drivers/net/ipa/ipa_endpoint.c
+++ b/drivers/net/ipa/ipa_endpoint.c
@@ -436,6 +436,8 @@ int ipa_endpoint_modem_exception_reset_all(struct ipa *ipa)
        /* XXX This should have a 1 second timeout */
        gsi_trans_commit_wait(trans);
 
+       ipa_cmd_pipeline_clear_wait(ipa);
+
        return 0;
 }
 
@@ -1178,7 +1180,30 @@ static bool ipa_endpoint_status_skip(struct ipa_endpoint *endpoint,
 static bool ipa_endpoint_status_tag(struct ipa_endpoint *endpoint,
                                    const struct ipa_status *status)
 {
-       return !!le16_get_bits(status->mask, IPA_STATUS_MASK_TAG_VALID_FMASK);
+       struct ipa_endpoint *command_endpoint;
+       struct ipa *ipa = endpoint->ipa;
+       u32 endpoint_id;
+
+       if (!le16_get_bits(status->mask, IPA_STATUS_MASK_TAG_VALID_FMASK))
+               return false;   /* No valid tag */
+
+       /* The status contains a valid tag.  We know the packet was sent to
+        * this endpoint (already verified by ipa_endpoint_status_skip()).
+        * If the packet came from the AP->command TX endpoint we know
+        * this packet was sent as part of the pipeline clear process.
+        */
+       endpoint_id = u8_get_bits(status->endp_src_idx,
+                                 IPA_STATUS_SRC_IDX_FMASK);
+       command_endpoint = ipa->name_map[IPA_ENDPOINT_AP_COMMAND_TX];
+       if (endpoint_id == command_endpoint->endpoint_id) {
+               complete(&ipa->completion);
+       } else {
+               dev_err(&ipa->pdev->dev,
+                       "unexpected tagged packet from endpoint %u\n",
+                       endpoint_id);
+       }
+
+       return true;
 }
 
 /* Return whether the status indicates the packet should be dropped */

diff --git a/drivers/net/ipa/ipa_main.c b/drivers/net/ipa/ipa_main.c
index ab0fd5cb49277d724b58f92f853d193100a905a1..c10e7340b03186e34b1b39dcd5cf22b9d1ae4b40 100644 (file)
--- a/drivers/net/ipa/ipa_main.c
+++ b/drivers/net/ipa/ipa_main.c
@@ -831,6 +831,7 @@ static int ipa_probe(struct platform_device *pdev)
        dev_set_drvdata(dev, ipa);
        ipa->clock = clock;
        ipa->version = data->version;
+       init_completion(&ipa->completion);
 
        ret = ipa_reg_init(ipa);
        if (ret)