Merge tag 'imx-drivers-5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/shawnguo/linux into arm/drivers

i.MX drivers update for 5.5:
 - Skip return check for those SCU firmware APIs that are defined as
   void function in firmware.
 - Use established serial_number attribute instead of custom one to show
   SoC's unique ID for i.MX8 SoC drivers.
 - Read i.MX8MQ SOC revision from TF-A which parses ROM and exposes the
   value through a SMC call. This improves the situation that SOC
   revision reports 'unknown' on some older revisions.
 - Add a check and warn on unexpected SCU RX to avoid potential stack
   corruption in imx-scu driver.
 - Fix a sparse warning in imx-scu-irq driver by adding missing header.
 - Remove an unneeded call to devm_of_platform_populate() from imx-dsp
   driver.

* tag 'imx-drivers-5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/shawnguo/linux:
  soc: imx8mq: Read SOC revision from TF-A
  soc: imx-scu: Using existing serial_number instead of UID
  soc: imx8: Using existing serial_number instead of UID
  firmware: imx: add missing include of <linux/firmware/imx/sci.h>
  firmware: imx: Remove call to devm_of_platform_populate
  firmware: imx: Skip return value check for some special SCU firmware APIs
  firmware: imx: warn on unexpected RX

Link: https://lore.kernel.org/r/20191105150315.15477-1-shawnguo@kernel.org
Signed-off-by: Olof Johansson <olof@lixom.net>

3 files changed, 25 insertions, 2 deletions

diff --git a/drivers/firmware/imx/imx-dsp.c b/drivers/firmware/imx/imx-dsp.c
index a43d2db5cbdb..4265e9dbed84 100644
--- a/drivers/firmware/imx/imx-dsp.c
+++ b/drivers/firmware/imx/imx-dsp.c
@@ -114,7 +114,7 @@ static int imx_dsp_probe(struct platform_device *pdev)
 
 	dev_info(dev, "NXP i.MX DSP IPC initialized\n");
 
-	return devm_of_platform_populate(dev);
+	return 0;
 out:
 	kfree(chan_name);
 	for (j = 0; j < i; j++) {
diff --git a/drivers/firmware/imx/imx-scu-irq.c b/drivers/firmware/imx/imx-scu-irq.c
index 687121f8c4d5..db655e87cdc8 100644
--- a/drivers/firmware/imx/imx-scu-irq.c
+++ b/drivers/firmware/imx/imx-scu-irq.c
@@ -8,6 +8,7 @@
 
 #include <dt-bindings/firmware/imx/rsrc.h>
 #include <linux/firmware/imx/ipc.h>
+#include <linux/firmware/imx/sci.h>
 #include <linux/mailbox_client.h>
 
 #define IMX_SC_IRQ_FUNC_ENABLE	1
diff --git a/drivers/firmware/imx/imx-scu.c b/drivers/firmware/imx/imx-scu.c
index 04a24a863d6e..03b43b7a6d1d 100644
--- a/drivers/firmware/imx/imx-scu.c
+++ b/drivers/firmware/imx/imx-scu.c
@@ -107,6 +107,12 @@ static void imx_scu_rx_callback(struct mbox_client *c, void *msg)
 	struct imx_sc_rpc_msg *hdr;
 	u32 *data = msg;
 
+	if (!sc_ipc->msg) {
+		dev_warn(sc_ipc->dev, "unexpected rx idx %d 0x%08x, ignore!\n",
+				sc_chan->idx, *data);
+		return;
+	}
+
 	if (sc_chan->idx == 0) {
 		hdr = msg;
 		sc_ipc->rx_size = hdr->size;
@@ -156,6 +162,7 @@ static int imx_scu_ipc_write(struct imx_sc_ipc *sc_ipc, void *msg)
  */
 int imx_scu_call_rpc(struct imx_sc_ipc *sc_ipc, void *msg, bool have_resp)
 {
+	uint8_t saved_svc, saved_func;
 	struct imx_sc_rpc_msg *hdr;
 	int ret;
 
@@ -165,7 +172,11 @@ int imx_scu_call_rpc(struct imx_sc_ipc *sc_ipc, void *msg, bool have_resp)
 	mutex_lock(&sc_ipc->lock);
 	reinit_completion(&sc_ipc->done);
 
-	sc_ipc->msg = msg;
+	if (have_resp) {
+		sc_ipc->msg = msg;
+		saved_svc = ((struct imx_sc_rpc_msg *)msg)->svc;
+		saved_func = ((struct imx_sc_rpc_msg *)msg)->func;
+	}
 	sc_ipc->count = 0;
 	ret = imx_scu_ipc_write(sc_ipc, msg);
 	if (ret < 0) {
@@ -184,9 +195,20 @@ int imx_scu_call_rpc(struct imx_sc_ipc *sc_ipc, void *msg, bool have_resp)
 		/* response status is stored in hdr->func field */
 		hdr = msg;
 		ret = hdr->func;
+		/*
+		 * Some special SCU firmware APIs do NOT have return value
+		 * in hdr->func, but they do have response data, those special
+		 * APIs are defined as void function in SCU firmware, so they
+		 * should be treated as return success always.
+		 */
+		if ((saved_svc == IMX_SC_RPC_SVC_MISC) &&
+			(saved_func == IMX_SC_MISC_FUNC_UNIQUE_ID ||
+			 saved_func == IMX_SC_MISC_FUNC_GET_BUTTON_STATUS))
+			ret = 0;
 	}
 
 out:
+	sc_ipc->msg = NULL;
 	mutex_unlock(&sc_ipc->lock);
 
 	dev_dbg(sc_ipc->dev, "RPC SVC done\n");