Merge patch series "arm: mach-k3: remove some firewalls left over by ROM"

Bryan Brattlof <bb@ti.com> says:

This small series is here to remove some firewalls setup by ROM during
their boot and clean things up for Linux later on. Ideally this would be
a simple call to remove_fwl_configs() however the location of the
firewall is problematic (could potentially crash the core) when we're
currently executing from the memory region protected by the firewall.

So we need to introduce a function which allows us to disable specific
firewall regions and skip others to ensure boot stability.

Link: https://lore.kernel.org/r/20250414-firewalls-v1-0-89090085c08b@ti.com

3 files changed, 38 insertions, 0 deletions

diff --git a/arch/arm/mach-k3/am62x/am625_init.c b/arch/arm/mach-k3/am62x/am625_init.c
index 595fc391ac5..a422919fab1 100644
--- a/arch/arm/mach-k3/am62x/am625_init.c
+++ b/arch/arm/mach-k3/am62x/am625_init.c
@@ -29,6 +29,12 @@
 /* TISCI DEV ID for A53 Clock */
 #define AM62X_DEV_A53SS0_CORE_0_DEV_ID 135
 
+struct fwl_data rom_fwls[] = {
+	{ "SOC_DEVGRP_MAIN", 641, 1 },
+	{ "SOC_DEVGRP_MAIN", 642, 1 },
+	{ "SOC_DEVGRP_MAIN", 642, 2 },
+};
+
 /*
  * This uninitialized global variable would normal end up in the .bss section,
  * but the .bss is cleared between writing and reading this variable, so move
@@ -177,6 +183,7 @@ void board_init_f(ulong dummy)
 {
 	struct udevice *dev;
 	int ret;
+	int i;
 
 	if (IS_ENABLED(CONFIG_CPU_V7R)) {
 		setup_k3_mpu_regions();
@@ -261,6 +268,11 @@ void board_init_f(ulong dummy)
 	/* Output System Firmware version info */
 	k3_sysfw_print_ver();
 
+	/* Disable firewalls ROM has configured. */
+	if (IS_ENABLED(CONFIG_CPU_V7R))
+		for (i = 0; i < ARRAY_SIZE(rom_fwls); i++)
+			remove_fwl_region(&rom_fwls[i]);
+
 	if (IS_ENABLED(CONFIG_ESM_K3)) {
 		/* Probe/configure ESM0 */
 		ret = uclass_get_device_by_name(UCLASS_MISC, "esm@420000", &dev);
diff --git a/arch/arm/mach-k3/common.h b/arch/arm/mach-k3/common.h
index 7bd72da1de8..2ec60c7879a 100644
--- a/arch/arm/mach-k3/common.h
+++ b/arch/arm/mach-k3/common.h
@@ -35,6 +35,7 @@ enum k3_device_type {
 void setup_k3_mpu_regions(void);
 int early_console_init(void);
 void disable_linefill_optimization(void);
+int remove_fwl_region(struct fwl_data *fwl);
 void remove_fwl_configs(struct fwl_data *fwl_data, size_t fwl_data_size);
 int load_firmware(char *name_fw, char *name_loadaddr, u32 *loadaddr);
 void k3_sysfw_print_ver(void);
diff --git a/arch/arm/mach-k3/r5/common.c b/arch/arm/mach-k3/r5/common.c
index fd188e7c90e..0b6604039f3 100644
--- a/arch/arm/mach-k3/r5/common.c
+++ b/arch/arm/mach-k3/r5/common.c
@@ -253,6 +253,31 @@ void disable_linefill_optimization(void)
 	asm("mcr p15, 0, %0, c1, c0, 1" : : "r" (actlr));
 }
 
+int remove_fwl_region(struct fwl_data *fwl)
+{
+	struct ti_sci_handle *sci = get_ti_sci_handle();
+	struct ti_sci_fwl_ops *ops = &sci->ops.fwl_ops;
+	struct ti_sci_msg_fwl_region region;
+	int ret;
+
+	region.fwl_id = fwl->fwl_id;
+	region.region = fwl->regions;
+	region.n_permission_regs = 3;
+
+	ops->get_fwl_region(sci, &region);
+
+	/* zero out the enable field of the firewall */
+	region.control = region.control & ~0xF;
+
+	pr_debug("Disabling firewall id: %d region: %d\n",
+		 region.fwl_id, region.region);
+
+	ret = ops->set_fwl_region(sci, &region);
+	if (ret)
+		pr_err("Could not disable firewall\n");
+	return ret;
+}
+
 static void remove_fwl_regions(struct fwl_data fwl_data, size_t num_regions,
 			       enum k3_firewall_region_type fwl_type)
 {