Re: [PATCH] rpmsg: qcom_smd: Access APCS through mailbox framework

[Arun Kumar Neelakantam]

On 11/16/2017 12:38 PM, Bjorn Andersson wrote:

Attempt to acquire the APCS IPC through the mailbox framework and fall
back to the old syscon based approach, to allow us to move away from
using the syscon.

Signed-off-by: Bjorn Andersson <bjorn.anders...@linaro.org>

Reviewed-by: Arun Kumar Neelakantam <ane...@codeaurora.org>

---
  drivers/rpmsg/qcom_smd.c | 62 +++++++++++++++++++++++++++++++++---------------
  1 file changed, 43 insertions(+), 19 deletions(-)

diff --git a/drivers/rpmsg/qcom_smd.c b/drivers/rpmsg/qcom_smd.c
index b01774e9fac0..ef2a526ebc8f 100644
--- a/drivers/rpmsg/qcom_smd.c
+++ b/drivers/rpmsg/qcom_smd.c
@@ -14,6 +14,7 @@

#include <linux/interrupt.h>

  #include <linux/io.h>
+#include <linux/mailbox_client.h>
  #include <linux/mfd/syscon.h>
  #include <linux/module.h>
  #include <linux/of_irq.h>
@@ -107,6 +108,8 @@ static const struct {
   * @ipc_regmap:               regmap handle holding the outgoing ipc register
   * @ipc_offset:               offset within @ipc_regmap of the register for 
ipc
   * @ipc_bit:          bit in the register at @ipc_offset of @ipc_regmap
+ * @mbox_client:       mailbox client handle
+ * @mbox_chan:         apcs ipc mailbox channel handle
   * @channels:         list of all channels detected on this edge
   * @channels_lock:    guard for modifications of @channels
   * @allocated:                array of bitmaps representing already allocated 
channels
@@ -129,6 +132,9 @@ struct qcom_smd_edge {
        int ipc_offset;
        int ipc_bit;

+ struct mbox_client mbox_client;

+       struct mbox_chan *mbox_chan;
+
        struct list_head channels;
        spinlock_t channels_lock;

@@ -365,7 +371,12 @@ static void qcom_smd_signal_channel(struct qcom_smd_channel *channel)

  {
        struct qcom_smd_edge *edge = channel->edge;

- regmap_write(edge->ipc_regmap, edge->ipc_offset, BIT(edge->ipc_bit));

+       if (edge->mbox_chan) {
+               mbox_send_message(edge->mbox_chan, NULL);
+               mbox_client_txdone(edge->mbox_chan, 0);
+       } else {
+               regmap_write(edge->ipc_regmap, edge->ipc_offset, 
BIT(edge->ipc_bit));
+       }
  }

/*

@@ -1268,27 +1279,37 @@ static int qcom_smd_parse_edge(struct device *dev,
        key = "qcom,remote-pid";
        of_property_read_u32(node, key, &edge->remote_pid);

- syscon_np = of_parse_phandle(node, "qcom,ipc", 0);

-       if (!syscon_np) {
-               dev_err(dev, "no qcom,ipc node\n");
-               return -ENODEV;
-       }
+       edge->mbox_client.dev = dev;
+       edge->mbox_client.knows_txdone = true;
+       edge->mbox_chan = mbox_request_channel(&edge->mbox_client, 0);
+       if (IS_ERR(edge->mbox_chan)) {
+               if (PTR_ERR(edge->mbox_chan) != -ENODEV)
+                       return PTR_ERR(edge->mbox_chan);

- edge->ipc_regmap = syscon_node_to_regmap(syscon_np);

-       if (IS_ERR(edge->ipc_regmap))
-               return PTR_ERR(edge->ipc_regmap);
+               edge->mbox_chan = NULL;

- key = "qcom,ipc";

-       ret = of_property_read_u32_index(node, key, 1, &edge->ipc_offset);
-       if (ret < 0) {
-               dev_err(dev, "no offset in %s\n", key);
-               return -EINVAL;
-       }
+               syscon_np = of_parse_phandle(node, "qcom,ipc", 0);
+               if (!syscon_np) {
+                       dev_err(dev, "no qcom,ipc node\n");
+                       return -ENODEV;
+               }

- ret = of_property_read_u32_index(node, key, 2, &edge->ipc_bit);

-       if (ret < 0) {
-               dev_err(dev, "no bit in %s\n", key);
-               return -EINVAL;
+               edge->ipc_regmap = syscon_node_to_regmap(syscon_np);
+               if (IS_ERR(edge->ipc_regmap))
+                       return PTR_ERR(edge->ipc_regmap);
+
+               key = "qcom,ipc";
+               ret = of_property_read_u32_index(node, key, 1, 
&edge->ipc_offset);
+               if (ret < 0) {
+                       dev_err(dev, "no offset in %s\n", key);
+                       return -EINVAL;
+               }
+
+               ret = of_property_read_u32_index(node, key, 2, &edge->ipc_bit);
+               if (ret < 0) {
+                       dev_err(dev, "no bit in %s\n", key);
+                       return -EINVAL;
+               }
        }

ret = of_property_read_string(node, "label", &edge->name);

@@ -1394,6 +1415,8 @@ struct qcom_smd_edge *qcom_smd_register_edge(struct 
device *parent,
        return edge;

unregister_dev:

+       if (!IS_ERR_OR_NULL(edge->mbox_chan))
+               mbox_free_channel(edge->mbox_chan);
        put_device(&edge->dev);
        return ERR_PTR(ret);
  }
@@ -1422,6 +1445,7 @@ int qcom_smd_unregister_edge(struct qcom_smd_edge *edge)
        if (ret)
                dev_warn(&edge->dev, "can't remove smd device: %d\n", ret);

+ mbox_free_channel(edge->mbox_chan);

        device_unregister(&edge->dev);

return 0;