Merge tag 'scmi-fixes-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux into soc/fixes

Arm SCMI fixes for v6.3

Few fixes addressing issues around validation of device tree SCMI node,
allowing raw SCMI access even on systems which fail to probe the normal
driver stack, duplicate header inclusion, clean up return statement using
literal values instead of variable to simplify and use of devm_bitmap_zalloc
instead of devm_kcalloc to improve semantic.

* tag 'scmi-fixes-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux:
  firmware: arm_scmi: Use the bitmap API to allocate bitmaps
  firmware: arm_scmi: Fix device node validation for mailbox transport
  firmware: arm_scmi: Fix raw coexistence mode behaviour on failure path
  firmware: arm_scmi: Remove duplicate include header inclusion
  firmware: arm_scmi: Return a literal instead of a variable
  firmware: arm_scmi: Clean up a return statement in scmi_probe

Link: https://lore.kernel.org/r/20230315193557.1709241-1-sudeep.holla@arm.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

3 files changed, 45 insertions, 9 deletions

diff --git a/drivers/firmware/arm_scmi/bus.c b/drivers/firmware/arm_scmi/bus.c
index 73140b854b31..c15928b8c5cc 100644
--- a/drivers/firmware/arm_scmi/bus.c
+++ b/drivers/firmware/arm_scmi/bus.c
@@ -14,7 +14,6 @@
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/device.h>
-#include <linux/of.h>
 
 #include "common.h"
 
@@ -436,7 +435,7 @@ struct scmi_device *scmi_device_create(struct device_node *np,
 	/* Nothing to do. */
 	if (!phead) {
 		mutex_unlock(&scmi_requested_devices_mtx);
-		return scmi_dev;
+		return NULL;
 	}
 
 	/* Walk the list of requested devices for protocol and create them */
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index d21c7eafd641..dbc474ff62b7 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -2221,8 +2221,8 @@ static int __scmi_xfer_info_init(struct scmi_info *sinfo,
 	hash_init(info->pending_xfers);
 
 	/* Allocate a bitmask sized to hold MSG_TOKEN_MAX tokens */
-	info->xfer_alloc_table = devm_kcalloc(dev, BITS_TO_LONGS(MSG_TOKEN_MAX),
-					      sizeof(long), GFP_KERNEL);
+	info->xfer_alloc_table = devm_bitmap_zalloc(dev, MSG_TOKEN_MAX,
+						    GFP_KERNEL);
 	if (!info->xfer_alloc_table)
 		return -ENOMEM;
 
@@ -2657,6 +2657,7 @@ static int scmi_probe(struct platform_device *pdev)
 	struct scmi_handle *handle;
 	const struct scmi_desc *desc;
 	struct scmi_info *info;
+	bool coex = IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT_COEX);
 	struct device *dev = &pdev->dev;
 	struct device_node *child, *np = dev->of_node;
 
@@ -2731,16 +2732,13 @@ static int scmi_probe(struct platform_device *pdev)
 			dev_warn(dev, "Failed to setup SCMI debugfs.\n");
 
 		if (IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT)) {
-			bool coex =
-			      IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT_COEX);
-
 			ret = scmi_debugfs_raw_mode_setup(info);
 			if (!coex) {
 				if (ret)
 					goto clear_dev_req_notifier;
 
-				/* Bail out anyway when coex enabled */
-				return ret;
+				/* Bail out anyway when coex disabled. */
+				return 0;
 			}
 
 			/* Coex enabled, carry on in any case. */
@@ -2764,6 +2762,8 @@ static int scmi_probe(struct platform_device *pdev)
 	ret = scmi_protocol_acquire(handle, SCMI_PROTOCOL_BASE);
 	if (ret) {
 		dev_err(dev, "unable to communicate with SCMI\n");
+		if (coex)
+			return 0;
 		goto notification_exit;
 	}
 
diff --git a/drivers/firmware/arm_scmi/mailbox.c b/drivers/firmware/arm_scmi/mailbox.c
index 0d9c9538b7f4..112c285deb97 100644
--- a/drivers/firmware/arm_scmi/mailbox.c
+++ b/drivers/firmware/arm_scmi/mailbox.c
@@ -52,6 +52,39 @@ static bool mailbox_chan_available(struct device_node *of_node, int idx)
 					   "#mbox-cells", idx, NULL);
 }
 
+static int mailbox_chan_validate(struct device *cdev)
+{
+	int num_mb, num_sh, ret = 0;
+	struct device_node *np = cdev->of_node;
+
+	num_mb = of_count_phandle_with_args(np, "mboxes", "#mbox-cells");
+	num_sh = of_count_phandle_with_args(np, "shmem", NULL);
+	/* Bail out if mboxes and shmem descriptors are inconsistent */
+	if (num_mb <= 0 || num_sh > 2 || num_mb != num_sh) {
+		dev_warn(cdev, "Invalid channel descriptor for '%s'\n",
+			 of_node_full_name(np));
+		return -EINVAL;
+	}
+
+	if (num_sh > 1) {
+		struct device_node *np_tx, *np_rx;
+
+		np_tx = of_parse_phandle(np, "shmem", 0);
+		np_rx = of_parse_phandle(np, "shmem", 1);
+		/* SCMI Tx and Rx shared mem areas have to be distinct */
+		if (!np_tx || !np_rx || np_tx == np_rx) {
+			dev_warn(cdev, "Invalid shmem descriptor for '%s'\n",
+				 of_node_full_name(np));
+			ret = -EINVAL;
+		}
+
+		of_node_put(np_tx);
+		of_node_put(np_rx);
+	}
+
+	return ret;
+}
+
 static int mailbox_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,
 			      bool tx)
 {
@@ -64,6 +97,10 @@ static int mailbox_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,
 	resource_size_t size;
 	struct resource res;
 
+	ret = mailbox_chan_validate(cdev);
+	if (ret)
+		return ret;
+
 	smbox = devm_kzalloc(dev, sizeof(*smbox), GFP_KERNEL);
 	if (!smbox)
 		return -ENOMEM;