LCM: Enable parity on only some DCUs

Previously parity had to either be enabled on all DCUs or none of them,
now they can be enabled for subsets, provided that subset starts from
the lowest DCU register.

Change-Id: Ia7c0601be12e7c053dfe47b3f5f1e7aba3bb745c
Signed-off-by: Raef Coles <raef.coles@arm.com>

Author: RcColes

platform/ext/target/arm/drivers/lcm/lcm_drv.c

@@ -22,11 +22,12 @@
 #include <assert.h>
 
 #ifdef LCM_DCU_PARITY
-#define DCU_ENABLED_MASK  0x55555555
-#define DCU_DISABLED_MASK 0xAAAAAAAA
-#else
-#define DCU_ENABLED_MASK  0xFFFFFFFF
-#define DCU_DISABLED_MASK 0x00000000
+#define DCU_PARITY_ENABLED_MASK 0x55555555
+#define DCU_PARITY_DISABLED_MASK 0xAAAAAAAA
+
+#ifndef LCM_DCU_PARITY_WORDS
+#define LCM_DCU_PARITY_WORDS 4
+#endif
 #endif
 
 #ifdef INTEGRITY_CHECKER_S
@@ -94,6 +95,26 @@ struct _lcm_reg_map_t {
     };
 };
 
+static uint32_t get_enabled_mask(uint32_t dcu_word_idx)
+{
+#ifndef LCM_DCU_PARITY
+    (void)dcu_word_idx;
+    return 0xFFFFFFFF;
+#else
+    return dcu_word_idx < LCM_DCU_PARITY_WORDS ? DCU_PARITY_ENABLED_MASK : 0xFFFFFFFF;
+#endif
+}
+
+static uint32_t get_disabled_mask(uint32_t dcu_word_idx)
+{
+#ifndef LCM_DCU_PARITY
+    (void)dcu_word_idx;
+    return 0x00000000;
+#else
+    return dcu_word_idx < LCM_DCU_PARITY_WORDS ? DCU_PARITY_DISABLED_MASK : 0x00000000;
+#endif
+}
+
 static int is_pointer_word_aligned(void *ptr) {
     return !((uintptr_t)ptr & (sizeof(uint32_t) - 1));
 }
@@ -268,13 +289,13 @@ static inline void mask_dcus_for_sp_enable(struct lcm_dev_t *dev)
     for (idx = 0; idx < LCM_DCU_WIDTH_IN_BYTES / sizeof(uint32_t); idx++) {
         mask_val = p_lcm->dcu_sp_disable_mask[idx];
 
-        mask_enabled = mask_val & DCU_ENABLED_MASK;
-        mask_disabled = mask_val & DCU_DISABLED_MASK;
+        mask_enabled = mask_val & get_enabled_mask(idx);
+        mask_disabled = mask_val & get_disabled_mask(idx);
 
         dcu_val = p_lcm->dcu_en[idx];
 
         dcu_val &= mask_enabled;
-        dcu_val |= ((~dcu_val & DCU_ENABLED_MASK) << 1) & mask_disabled;
+        dcu_val |= ((~dcu_val & get_enabled_mask(idx)) << 1) & mask_disabled;
 
         p_lcm->dcu_en[idx] = dcu_val;
     }

platform/ext/target/arm/rse/common/CMakeLists.txt

@@ -55,6 +55,7 @@ target_compile_definitions(platform_region_defs
         RSE_TP_MODE=LCM_TP_MODE_${RSE_TP_MODE}
         RSE_TESTS_TP_MODE=LCM_TP_MODE_${RSE_TESTS_TP_MODE}
         LCM_DCU_PARITY
+        LCM_DCU_PARITY_WORDS=1
         $<$<BOOL:${PLAT_MHU_VERSION}>:PLAT_MHU_VERSION=${PLAT_MHU_VERSION}>
         $<$<BOOL:${RSE_BL1_TEST_BINARY}>:RSE_BL1_TEST_BINARY>
         $<$<BOOL:${RSE_TEST_BINARY_IN_ROM}>:RSE_TEST_BINARY_IN_ROM>