firmware: zynqmp: Probe driver before use

Probe the driver before use to ensure that the driver is always
available and the global data are valid. Initialize the global data
with zero and probe the driver if the global data are still zero. This
allows a usage of the firmware functions from other drivers with
arbitrary order between the drivers.

Signed-off-by: Stefan Herbrechtsmeier <stefan.herbrechtsmeier@weidmueller.com>
Link: https://lore.kernel.org/r/20220620163650.18756-2-stefan.herbrechtsmeier-oss@weidmueller.com
Signed-off-by: Michal Simek <michal.simek@amd.com>

diff --git a/drivers/firmware/firmware-zynqmp.c b/drivers/firmware/firmware-zynqmp.c
index 341d7cf..b0cd647 100644 (file)
--- a/drivers/firmware/firmware-zynqmp.c
+++ b/drivers/firmware/firmware-zynqmp.c
@@ -26,7 +26,7 @@
 struct zynqmp_power {
        struct mbox_chan tx_chan;
        struct mbox_chan rx_chan;
-} zynqmp_power;
+} zynqmp_power = {};
 
 #define NODE_ID_LOCATION       5
 
@@ -79,6 +79,20 @@ int zynqmp_pmufw_node(u32 id)
        return 0;
 }
 
+static int do_pm_probe(void)
+{
+       struct udevice *dev;
+       int ret;
+
+       ret = uclass_get_device_by_driver(UCLASS_FIRMWARE,
+                                         DM_DRIVER_GET(zynqmp_power),
+                                         &dev);
+       if (ret)
+               debug("%s: Probing device failed: %d\n", __func__, ret);
+
+       return ret;
+}
+
 static int ipi_req(const u32 *req, size_t req_len, u32 *res, size_t res_maxlen)
 {
        struct zynqmp_ipi_msg msg;
@@ -92,8 +106,11 @@ static int ipi_req(const u32 *req, size_t req_len, u32 *res, size_t res_maxlen)
            res_maxlen > PMUFW_PAYLOAD_ARG_CNT)
                return -EINVAL;
 
-       if (!(zynqmp_power.tx_chan.dev) || !(zynqmp_power.rx_chan.dev))
-               return -EINVAL;
+       if (!(zynqmp_power.tx_chan.dev) || !(zynqmp_power.rx_chan.dev)) {
+               ret = do_pm_probe();
+               if (ret)
+                       return ret;
+       }
 
        debug("%s, Sending IPI message with ID: 0x%0x\n", __func__, req[0]);
        msg.buf = (u32 *)req;