ti: k3: common: Add support for runtime detection of GICR base address

Valid addresses for GICR base are always a set calculable distance from
the GICD and is based on the number of cores a given instance of GICv3 IP
can support. The formula for the number of address bits is given by the
ARM GIC-500 TRM section 3.2 as 2^(18+log2(cores)) with the MSB set to
one for GICR instances. Holes in the GIC address space are also
guaranteed to safely return 0 on reads. This allows us to support runtime
detection of the GICR base address by starting from GIC base address plus
BIT(18) and walking until the GICR ID register (IIDR) is detected. We
stop searching after BIT(20) to prevent searching out into space if
something goes wrong. This can be extended out if we ever have a device
with 16 or more cores.
Signed-off-by: Andrew F. Davis <afd@ti.com>

include/drivers/arm/gicv3.h

@@ -84,6 +84,7 @@
 #define GICR_PCPUBASE_SHIFT	0x11
 #define GICR_SGIBASE_OFFSET	U(65536)	/* 64 KB */
 #define GICR_CTLR		U(0x0)
+#define GICR_IIDR		U(0x04)
 #define GICR_TYPER		U(0x08)
 #define GICR_WAKER		U(0x14)
 #define GICR_PROPBASER		U(0x70)

plat/ti/k3/common/k3_bl31_setup.c

@@ -23,8 +23,7 @@
 const mmap_region_t plat_k3_mmap[] = {
 	MAP_REGION_FLAT(SHARED_RAM_BASE, SHARED_RAM_SIZE, MT_DEVICE | MT_RW | MT_SECURE),
 	MAP_REGION_FLAT(K3_USART_BASE_ADDRESS, K3_USART_SIZE, MT_DEVICE | MT_RW | MT_SECURE),
-	MAP_REGION_FLAT(K3_GICD_BASE, K3_GICD_SIZE, MT_DEVICE | MT_RW | MT_SECURE),
-	MAP_REGION_FLAT(K3_GICR_BASE, K3_GICR_SIZE, MT_DEVICE | MT_RW | MT_SECURE),
+	MAP_REGION_FLAT(K3_GIC_BASE, K3_GIC_SIZE, MT_DEVICE | MT_RW | MT_SECURE),
 	MAP_REGION_FLAT(SEC_PROXY_RT_BASE, SEC_PROXY_RT_SIZE, MT_DEVICE | MT_RW | MT_SECURE),
 	MAP_REGION_FLAT(SEC_PROXY_SCFG_BASE, SEC_PROXY_SCFG_SIZE, MT_DEVICE | MT_RW | MT_SECURE),
 	MAP_REGION_FLAT(SEC_PROXY_DATA_BASE, SEC_PROXY_DATA_SIZE, MT_DEVICE | MT_RW | MT_SECURE),
@@ -116,7 +115,7 @@ void bl31_plat_arch_setup(void)
 
 void bl31_platform_setup(void)
 {
-	k3_gic_driver_init(K3_GICD_BASE, K3_GICR_BASE);
+	k3_gic_driver_init(K3_GIC_BASE);
 	k3_gic_init();
 
 	ti_sci_init();

plat/ti/k3/common/k3_gicv3.c

@@ -6,10 +6,12 @@
 
 #include <platform_def.h>
 
+#include <assert.h>
 #include <common/bl_common.h>
 #include <common/interrupt_props.h>
 #include <drivers/arm/gicv3.h>
 #include <lib/utils.h>
+#include <lib/mmio.h>
 #include <plat/common/platform.h>
 
 #include <k3_gicv3.h>
@@ -35,8 +37,25 @@ gicv3_driver_data_t k3_gic_data = {
 	.mpidr_to_core_pos = k3_mpidr_to_core_pos,
 };
 
-void k3_gic_driver_init(uintptr_t gicd_base, uintptr_t gicr_base)
+void k3_gic_driver_init(uintptr_t gic_base)
 {
+	/* GIC Distributor is always at the base of the IP */
+	uintptr_t gicd_base = gic_base;
+	/* GIC Redistributor base is run-time detected */
+	uintptr_t gicr_base = 0;
+
+	for (unsigned int gicr_shift = 18; gicr_shift < 21; gicr_shift++) {
+		uintptr_t gicr_check = gic_base + BIT(gicr_shift);
+		uint32_t iidr = mmio_read_32(gicr_check + GICR_IIDR);
+		if (iidr != 0) {
+			/* Found the GICR base */
+			gicr_base = gicr_check;
+			break;
+		}
+	}
+	/* Assert if we have not found the GICR base */
+	assert(gicr_base != 0);
+
 	/*
 	 * The GICv3 driver is initialized in EL3 and does not need
 	 * to be initialized again in SEL1. This is because the S-EL1

plat/ti/k3/include/k3_gicv3.h

@@ -9,7 +9,7 @@
 
 #include <stdint.h>
 
-void k3_gic_driver_init(uintptr_t gicd_base, uintptr_t gicr_base);
+void k3_gic_driver_init(uintptr_t gic_base);
 void k3_gic_init(void);
 void k3_gic_cpuif_enable(void);
 void k3_gic_cpuif_disable(void);

plat/ti/k3/include/platform_def.h

@@ -185,10 +185,8 @@
 	INTR_PROP_DESC(ARM_IRQ_SEC_SGI_6, GIC_HIGHEST_SEC_PRIORITY, grp, \
 			GIC_INTR_CFG_EDGE)
 
-#define K3_GICD_BASE  0x01800000
-#define K3_GICD_SIZE  0x10000
-#define K3_GICR_BASE  0x01880000
-#define K3_GICR_SIZE  0x100000
+#define K3_GIC_BASE	0x01800000
+#define K3_GIC_SIZE	0x200000
 
 #define SEC_PROXY_DATA_BASE	0x32C00000
 #define SEC_PROXY_DATA_SIZE	0x80000