Merge pull request #912 from vwadekar/tegra-smmu-ctx-save-robust

Tegra: smmu: make the context save sequence robust

plat/nvidia/tegra/common/drivers/smmu/smmu.c

@@ -87,7 +87,7 @@ static void tegra_smmu_write_32(uint32_t smmu_id,
  */
 void tegra_smmu_save_context(uint64_t smmu_ctx_addr)
 {
-	uint32_t i;
+	uint32_t i, num_entries = 0;
 	smmu_regs_t *smmu_ctx_regs;
 #if DEBUG
 	plat_params_from_bl2_t *params_from_bl2 = bl31_get_plat_params();
@@ -110,13 +110,29 @@ void tegra_smmu_save_context(uint64_t smmu_ctx_addr)
 	smmu_ctx_regs = plat_get_smmu_ctx();
 	assert(smmu_ctx_regs);
 
+	/*
+	 * smmu_ctx_regs[0].val contains the size of the context table minus
+	 * the last entry. Sanity check the table size before we start with
+	 * the context save operation.
+	 */
+	while (smmu_ctx_regs[num_entries].val != 0xFFFFFFFFU) {
+		num_entries++;
+	}
+
+	/* panic if the sizes do not match */
+	if (num_entries != smmu_ctx_regs[0].val)
+		panic();
+
 	/* save SMMU register values */
-	for (i = 1; i < smmu_ctx_regs[0].val; i++)
+	for (i = 1; i < num_entries; i++)
 		smmu_ctx_regs[i].val = mmio_read_32(smmu_ctx_regs[i].reg);
 
+	/* increment by 1 to take care of the last entry */
+	num_entries++;
+
 	/* Save SMMU config settings */
 	memcpy16((void *)(uintptr_t)smmu_ctx_addr, (void *)smmu_ctx_regs,
-		 sizeof(smmu_regs_t));
+		 (sizeof(smmu_regs_t) * num_entries));
 
 	/* save the SMMU table address */
 	mmio_write_32(TEGRA_SCRATCH_BASE + SECURE_SCRATCH_RSV11_LO,

plat/nvidia/tegra/soc/t186/plat_psci_handlers.c

@@ -46,11 +46,8 @@
 
 extern void prepare_cpu_pwr_dwn(void);
 extern void tegra186_cpu_reset_handler(void);
-extern uint32_t __tegra186_cpu_reset_handler_data,
-		__tegra186_cpu_reset_handler_end;
-
-/* TZDRAM offset for saving SMMU context */
-#define TEGRA186_SMMU_CTX_OFFSET	16
+extern uint32_t __tegra186_cpu_reset_handler_end,
+		__tegra186_smmu_context;
 
 /* state id mask */
 #define TEGRA186_STATE_ID_MASK		0xF
@@ -151,9 +148,8 @@ int tegra_soc_pwr_domain_suspend(const psci_power_state_t *target_state)
 
 		/* save SMMU context to TZDRAM */
 		smmu_ctx_base = params_from_bl2->tzdram_base +
-			((uintptr_t)&__tegra186_cpu_reset_handler_data -
-			 (uintptr_t)tegra186_cpu_reset_handler) +
-			TEGRA186_SMMU_CTX_OFFSET;
+			((uintptr_t)&__tegra186_smmu_context -
+			 (uintptr_t)tegra186_cpu_reset_handler);
 		tegra_smmu_save_context((uintptr_t)smmu_ctx_base);
 
 		/* Prepare for system suspend */

plat/nvidia/tegra/soc/t186/plat_trampoline.S

@@ -94,6 +94,8 @@ endfunc tegra186_cpu_reset_handler
 __tegra186_cpu_reset_handler_data:
 	.quad	tegra_secure_entrypoint
 	.quad	__BL31_END__ - BL31_BASE
+	.globl	__tegra186_smmu_context
+__tegra186_smmu_context:
 	.rept	TEGRA186_SMMU_CTX_SIZE
 	.quad	0
 	.endr