This will add support for ACPI parsing of the mboxes attribute
when booting with ACPI table. The client will have a attribute
mimic the dts call "mboxes". In the ACPI case, the client will
mark "mboxes" with the ACPI HID of the mbox it wishes to use.

        Name (_DSD, Package () {
                ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
                Package () {
                        Package (2) {"mboxes", "ACPIHID"},
                }
        })

Signed-off-by: Feng Kan <f...@apm.com>
---
 drivers/mailbox/mailbox.c          | 121 +++++++++++++++++++++++++++++--------
 include/linux/mailbox_controller.h |   2 +
 2 files changed, 99 insertions(+), 24 deletions(-)

diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c
index 19b491d..9f2d0e3 100644
--- a/drivers/mailbox/mailbox.c
+++ b/drivers/mailbox/mailbox.c
@@ -9,6 +9,7 @@
  * published by the Free Software Foundation.
  */
 
+#include <linux/acpi.h>
 #include <linux/interrupt.h>
 #include <linux/spinlock.h>
 #include <linux/mutex.h>
@@ -278,6 +279,87 @@ int mbox_send_message(struct mbox_chan *chan, void *mssg)
 }
 EXPORT_SYMBOL_GPL(mbox_send_message);
 
+static acpi_status
+mbox_acpi_find(acpi_handle handle, u32 lvl, void *context, void **rv)
+{
+       struct acpi_device *acpi_dev;
+
+       if (acpi_bus_get_device(handle, &acpi_dev))
+               return AE_OK;
+
+       if (strcmp(acpi_device_hid(acpi_dev), (const char *)context) == 0)
+               *rv = acpi_dev;
+
+       return AE_OK;
+}
+
+static struct mbox_chan *mbox_acpi_parse_chan(struct device *dev, int index)
+{
+       const char *mbox_attr = "mboxes";
+       struct acpi_device *acpi_dev;
+       struct mbox_controller *mbox;
+       struct mbox_chan *chan;
+       int status;
+       char *hid_str;
+
+       status = device_property_read_string(dev, mbox_attr,
+                                            (const char **)&hid_str);
+       if (status)
+               return ERR_PTR(-ENODEV);
+
+       status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
+                                    ACPI_UINT32_MAX, mbox_acpi_find, NULL,
+                                    (void *)hid_str, (void **)&acpi_dev);
+       if (ACPI_FAILURE(status) || !acpi_dev) {
+               dev_dbg(dev, "mbox: no matching mboxes %s found in ACPI 
table\n",
+                       hid_str);
+               return ERR_PTR(-ENODEV);
+       }
+
+       chan = NULL;
+       list_for_each_entry(mbox, &mbox_cons, node)
+               if (ACPI_COMPANION(mbox->dev) == acpi_dev) {
+                       chan = mbox->acpi_xlate(mbox, index);
+                       break;
+               }
+
+       return chan;
+}
+
+static struct mbox_chan *mbox_of_parse_chan(struct device *dev, int index)
+{
+       struct of_phandle_args spec;
+       struct mbox_controller *mbox;
+       struct mbox_chan *chan;
+
+       if (of_parse_phandle_with_args(dev->of_node, "mboxes",
+                                      "#mbox-cells", index, &spec)) {
+               dev_dbg(dev, "%s: can't parse \"mboxes\" property\n", __func__);
+               return ERR_PTR(-ENODEV);
+       }
+
+       chan = NULL;
+       list_for_each_entry(mbox, &mbox_cons, node)
+               if (mbox->dev->of_node == spec.np) {
+                       chan = mbox->of_xlate(mbox, &spec);
+                       break;
+               }
+
+       of_node_put(spec.np);
+       return chan;
+}
+
+static struct mbox_chan *mbox_parse_chan(struct device *dev, int index)
+{
+       if (!dev)
+               return ERR_PTR(-ENODEV);
+
+       if (dev->of_node)
+               return mbox_of_parse_chan(dev, index);
+       else
+               return mbox_acpi_parse_chan(dev, index);
+}
+
 /**
  * mbox_request_channel - Request a mailbox channel.
  * @cl: Identity of the client requesting the channel.
@@ -298,36 +380,15 @@ EXPORT_SYMBOL_GPL(mbox_send_message);
 struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index)
 {
        struct device *dev = cl->dev;
-       struct mbox_controller *mbox;
-       struct of_phandle_args spec;
        struct mbox_chan *chan;
        unsigned long flags;
        int ret;
 
-       if (!dev || !dev->of_node) {
-               pr_debug("%s: No owner device node\n", __func__);
-               return ERR_PTR(-ENODEV);
-       }
-
        mutex_lock(&con_mutex);
+       chan = mbox_parse_chan(dev, index);
 
-       if (of_parse_phandle_with_args(dev->of_node, "mboxes",
-                                      "#mbox-cells", index, &spec)) {
-               dev_dbg(dev, "%s: can't parse \"mboxes\" property\n", __func__);
-               mutex_unlock(&con_mutex);
-               return ERR_PTR(-ENODEV);
-       }
-
-       chan = NULL;
-       list_for_each_entry(mbox, &mbox_cons, node)
-               if (mbox->dev->of_node == spec.np) {
-                       chan = mbox->of_xlate(mbox, &spec);
-                       break;
-               }
-
-       of_node_put(spec.np);
-
-       if (!chan || chan->cl || !try_module_get(mbox->dev->driver->owner)) {
+       if (!chan || chan->cl ||
+           !try_module_get(chan->mbox->dev->driver->owner)) {
                dev_dbg(dev, "%s: mailbox not free\n", __func__);
                mutex_unlock(&con_mutex);
                return ERR_PTR(-EBUSY);
@@ -384,6 +445,15 @@ void mbox_free_channel(struct mbox_chan *chan)
 EXPORT_SYMBOL_GPL(mbox_free_channel);
 
 static struct mbox_chan *
+acpi_mbox_index_xlate(struct mbox_controller *mbox, int chan)
+{
+       if (chan >= mbox->num_chans)
+               return NULL;
+
+       return &mbox->chans[chan];
+}
+
+static struct mbox_chan *
 of_mbox_index_xlate(struct mbox_controller *mbox,
                    const struct of_phandle_args *sp)
 {
@@ -434,6 +504,9 @@ int mbox_controller_register(struct mbox_controller *mbox)
        if (!mbox->of_xlate)
                mbox->of_xlate = of_mbox_index_xlate;
 
+       if (!mbox->acpi_xlate)
+               mbox->acpi_xlate = acpi_mbox_index_xlate;
+
        mutex_lock(&con_mutex);
        list_add_tail(&mbox->node, &mbox_cons);
        mutex_unlock(&con_mutex);
diff --git a/include/linux/mailbox_controller.h 
b/include/linux/mailbox_controller.h
index d4cf96f..f61d9d4 100644
--- a/include/linux/mailbox_controller.h
+++ b/include/linux/mailbox_controller.h
@@ -80,6 +80,8 @@ struct mbox_controller {
        unsigned txpoll_period;
        struct mbox_chan *(*of_xlate)(struct mbox_controller *mbox,
                                      const struct of_phandle_args *sp);
+       struct mbox_chan *(*acpi_xlate)(struct mbox_controller *mbox,
+                                       int chan);
        /* Internal to API */
        struct timer_list poll;
        struct list_head node;
-- 
1.9.1

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