[PATCH] soc: qcom: smp2p: Access APCS as mailbox client

[Bjorn Andersson]

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>
---
 drivers/soc/qcom/Kconfig |  1 +
 drivers/soc/qcom/smp2p.c | 38 ++++++++++++++++++++++++++++++++------
 2 files changed, 33 insertions(+), 6 deletions(-)

diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
index b00bccddcd3b..e67d9534fca0 100644
--- a/drivers/soc/qcom/Kconfig
+++ b/drivers/soc/qcom/Kconfig
@@ -64,6 +64,7 @@ config QCOM_SMEM_STATE
 
 config QCOM_SMP2P
        tristate "Qualcomm Shared Memory Point to Point support"
+       depends on MAILBOX
        depends on QCOM_SMEM
        select QCOM_SMEM_STATE
        help
diff --git a/drivers/soc/qcom/smp2p.c b/drivers/soc/qcom/smp2p.c
index f51fb2ea7200..7fdbb64142a0 100644
--- a/drivers/soc/qcom/smp2p.c
+++ b/drivers/soc/qcom/smp2p.c
@@ -18,6 +18,7 @@
 #include <linux/of.h>
 #include <linux/irq.h>
 #include <linux/irqdomain.h>
+#include <linux/mailbox_client.h>
 #include <linux/mfd/syscon.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
@@ -126,6 +127,8 @@ struct smp2p_entry {
  * @ipc_regmap:        regmap for the outbound ipc
  * @ipc_offset:        offset within the regmap
  * @ipc_bit:   bit in regmap@offset to kick to signal remote processor
+ * @mbox_client: mailbox client handle
+ * @mbox_chan: apcs ipc mailbox channel handle
  * @inbound:   list of inbound entries
  * @outbound:  list of outbound entries
  */
@@ -146,6 +149,9 @@ struct qcom_smp2p {
        int ipc_offset;
        int ipc_bit;
 
+       struct mbox_client mbox_client;
+       struct mbox_chan *mbox_chan;
+
        struct list_head inbound;
        struct list_head outbound;
 };
@@ -154,7 +160,13 @@ static void qcom_smp2p_kick(struct qcom_smp2p *smp2p)
 {
        /* Make sure any updated data is written before the kick */
        wmb();
-       regmap_write(smp2p->ipc_regmap, smp2p->ipc_offset, BIT(smp2p->ipc_bit));
+
+       if (smp2p->mbox_chan) {
+               mbox_send_message(smp2p->mbox_chan, NULL);
+               mbox_client_txdone(smp2p->mbox_chan, 0);
+       } else {
+               regmap_write(smp2p->ipc_regmap, smp2p->ipc_offset, 
BIT(smp2p->ipc_bit));
+       }
 }
 
 /**
@@ -453,10 +465,6 @@ static int qcom_smp2p_probe(struct platform_device *pdev)
 
        platform_set_drvdata(pdev, smp2p);
 
-       ret = smp2p_parse_ipc(smp2p);
-       if (ret)
-               return ret;
-
        key = "qcom,smem";
        ret = of_property_read_u32_array(pdev->dev.of_node, key,
                                         smp2p->smem_items, 2);
@@ -483,9 +491,22 @@ static int qcom_smp2p_probe(struct platform_device *pdev)
                return irq;
        }
 
+       smp2p->mbox_client.dev = &pdev->dev;
+       smp2p->mbox_chan = mbox_request_channel(&smp2p->mbox_client, 0);
+       if (IS_ERR(smp2p->mbox_chan)) {
+               if (PTR_ERR(smp2p->mbox_chan) != -ENODEV)
+                       return PTR_ERR(smp2p->mbox_chan);
+
+               smp2p->mbox_chan = NULL;
+
+               ret = smp2p_parse_ipc(smp2p);
+               if (ret)
+                       return ret;
+       }
+
        ret = qcom_smp2p_alloc_outbound_item(smp2p);
        if (ret < 0)
-               return ret;
+               goto release_mbox;
 
        for_each_available_child_of_node(pdev->dev.of_node, node) {
                entry = devm_kzalloc(&pdev->dev, sizeof(*entry), GFP_KERNEL);
@@ -540,6 +561,9 @@ static int qcom_smp2p_probe(struct platform_device *pdev)
 
        smp2p->out->valid_entries = 0;
 
+release_mbox:
+       mbox_free_channel(smp2p->mbox_chan);
+
        return ret;
 }
 
@@ -554,6 +578,8 @@ static int qcom_smp2p_remove(struct platform_device *pdev)
        list_for_each_entry(entry, &smp2p->outbound, node)
                qcom_smem_state_unregister(entry->state);
 
+       mbox_free_channel(smp2p->mbox_chan);
+
        smp2p->out->valid_entries = 0;
 
        return 0;
-- 
2.15.0