[PATCH v4 2/7] remoteproc: k3: skip mapping firewalled lpm-metadata memory region

["Richard Genoud (TI)" <richard.genoud@bootlin.com>]

The region lpm-metadata is firewalled by TIFS on Jacinto devices, so it
should not be mapped to prevent speculative access crashes

Just skip this memory region during initialization.

Signed-off-by: Richard Genoud (TI) <richard.genoud@bootlin.com>
---
 drivers/remoteproc/ti_k3_common.c | 36 +++++++++++++++++++++----------
 1 file changed, 25 insertions(+), 11 deletions(-)

diff --git a/drivers/remoteproc/ti_k3_common.c b/drivers/remoteproc/ti_k3_common.c
index 3cb8ae5d72f6..5158e5e7c816 100644
--- a/drivers/remoteproc/ti_k3_common.c
+++ b/drivers/remoteproc/ti_k3_common.c
@@ -471,7 +471,7 @@ int k3_reserved_mem_init(struct k3_rproc *kproc)
 	struct device *dev = kproc->dev;
 	struct device_node *np = dev->of_node;
 	int num_rmems;
-	int ret, i;
+	int ret, i, j;
 
 	num_rmems = of_reserved_mem_region_count(np);
 	if (num_rmems < 0) {
@@ -501,30 +501,44 @@ int k3_reserved_mem_init(struct k3_rproc *kproc)
 		return -ENOMEM;
 
 	/* use remaining reserved memory regions for static carveouts */
-	for (i = 0; i < num_rmems; i++) {
+	for (j = 0, i = 0; i < num_rmems; i++) {
 		struct resource res;
+		const char *region_name;
 
 		ret = of_reserved_mem_region_to_resource(np, i + 1, &res);
 		if (ret)
 			return ret;
 
-		kproc->rmem[i].bus_addr = res.start;
+		ret = of_property_read_string_index(np, "memory-region-names",
+						    i + 1, &region_name);
+		/*
+		 * lpm-metadata is a firewalled region accessible only by TIFS.
+		 * Skip mapping it to avoid speculative access crashes.
+		 */
+		if (!ret && !strcmp(region_name, "lpm-metadata")) {
+			dev_dbg(dev, "Skipping firewalled memory region %s @0x%x\n",
+				region_name, (u32)res.start);
+			continue;
+		}
+
+		kproc->rmem[j].bus_addr = res.start;
 		/* 64-bit address regions currently not supported */
-		kproc->rmem[i].dev_addr = (u32)res.start;
-		kproc->rmem[i].size = resource_size(&res);
-		kproc->rmem[i].cpu_addr = devm_ioremap_resource_wc(dev, &res);
-		if (IS_ERR(kproc->rmem[i].cpu_addr)) {
+		kproc->rmem[j].dev_addr = (u32)res.start;
+		kproc->rmem[j].size = resource_size(&res);
+		kproc->rmem[j].cpu_addr = devm_ioremap_resource_wc(dev, &res);
+		if (IS_ERR(kproc->rmem[j].cpu_addr)) {
 			dev_err(dev, "failed to map reserved memory#%d at %pR\n",
 				i + 1, &res);
 			return -ENOMEM;
 		}
 
 		dev_dbg(dev, "reserved memory%d: bus addr %pa size 0x%zx va %p da 0x%x\n",
-			i + 1, &kproc->rmem[i].bus_addr,
-			kproc->rmem[i].size, kproc->rmem[i].cpu_addr,
-			kproc->rmem[i].dev_addr);
+			j + 1, &kproc->rmem[j].bus_addr,
+			kproc->rmem[j].size, kproc->rmem[j].cpu_addr,
+			kproc->rmem[j].dev_addr);
+		j++;
 	}
-	kproc->num_rmems = num_rmems;
+	kproc->num_rmems = j;
 
 	return 0;
 }