feat(gicv3): multichip: detect GIC-700 at runtime

At the moment we have a GIC_ENABLE_V4_EXTN build time variable to
determine whether the GIC interrupt controller is compliant to version
4.0 of the GIC spec or not.
In case of the GIC-600 multichip support we were somewhat abusing that
flag to differentiate between a GIC-700 and GIC-600 implementation
being used in the system.

To avoid a build time dependency on this flag, look at the GICD_IIDR
register and check if the hardware is a GIC-600 or not, to make this
decision at runtime. We then use the values for either GIC-700 or the
GIC-600, respectively.

Change-Id: I8c09ec1cd6fd60d28da879ed55ffef5506f9869d
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
diff --git a/drivers/arm/gic/v3/gic600_multichip.c b/drivers/arm/gic/v3/gic600_multichip.c
index ca7c43b..fd3d8c2 100644
--- a/drivers/arm/gic/v3/gic600_multichip.c
+++ b/drivers/arm/gic/v3/gic600_multichip.c
@@ -11,6 +11,7 @@
 #include <assert.h>
 
 #include <common/debug.h>
+#include <drivers/arm/arm_gicv3_common.h>
 #include <drivers/arm/gic600_multichip.h>
 #include <drivers/arm/gicv3.h>
 
@@ -73,6 +74,7 @@
 				unsigned int spi_id_max)
 {
 	unsigned int spi_block_min, spi_blocks;
+	unsigned int gicd_iidr_val = gicd_read_iidr(base);
 	uint64_t chipr_n_val;
 
 	/*
@@ -100,8 +102,24 @@
 	spi_block_min = SPI_BLOCK_MIN_VALUE(spi_id_min);
 	spi_blocks    = SPI_BLOCKS_VALUE(spi_id_min, spi_id_max);
 
-	chipr_n_val = (GICD_CHIPR_VALUE(chip_addr, spi_block_min, spi_blocks)) |
-		GICD_CHIPRx_SOCKET_STATE;
+	switch ((gicd_iidr_val & IIDR_MODEL_MASK)) {
+	case IIDR_MODEL_ARM_GIC_600:
+		chipr_n_val = GICD_CHIPR_VALUE_GIC_600(chip_addr,
+						       spi_block_min,
+						       spi_blocks);
+		break;
+	case IIDR_MODEL_ARM_GIC_700:
+		chipr_n_val = GICD_CHIPR_VALUE_GIC_700(chip_addr,
+						       spi_block_min,
+						       spi_blocks);
+		break;
+	default:
+		ERROR("Unsupported GIC model 0x%x for multichip setup.\n",
+		      gicd_iidr_val);
+		panic();
+		break;
+	}
+	chipr_n_val |= GICD_CHIPRx_SOCKET_STATE;
 
 	/*
 	 * Wait for DCHIPR.PUP to be zero before commencing writes to
diff --git a/drivers/arm/gic/v3/gic600_multichip_private.h b/drivers/arm/gic/v3/gic600_multichip_private.h
index 27b8e81..5d1ff6a 100644
--- a/drivers/arm/gic/v3/gic600_multichip_private.h
+++ b/drivers/arm/gic/v3/gic600_multichip_private.h
@@ -27,17 +27,11 @@
 #define GICD_CHIPSR_RTS_SHIFT		4
 #define GICD_DCHIPR_RT_OWNER_SHIFT	4
 
-/*
- * If GIC v4 extension is enabled, then use SPI macros specific to GIC-700.
- * Other shifts and mask remains same between GIC-600 and GIC-700.
- */
-#if GIC_ENABLE_V4_EXTN
-#define GICD_CHIPRx_SPI_BLOCK_MIN_SHIFT	9
-#define GICD_CHIPRx_SPI_BLOCKS_SHIFT	3
-#else
-#define GICD_CHIPRx_SPI_BLOCK_MIN_SHIFT	10
-#define GICD_CHIPRx_SPI_BLOCKS_SHIFT	5
-#endif
+/* Other shifts and masks remain the same between GIC-600 and GIC-700. */
+#define GIC_700_SPI_BLOCK_MIN_SHIFT	9
+#define GIC_700_SPI_BLOCKS_SHIFT	3
+#define GIC_600_SPI_BLOCK_MIN_SHIFT	10
+#define GIC_600_SPI_BLOCKS_SHIFT	5
 
 #define GICD_CHIPSR_RTS_STATE_DISCONNECTED	U(0)
 #define GICD_CHIPSR_RTS_STATE_UPDATING		U(1)
@@ -59,10 +53,14 @@
 #define SPI_BLOCKS_VALUE(spi_id_min, spi_id_max) \
 			(((spi_id_max) - (spi_id_min) + 1) / \
 			GIC600_SPI_ID_MIN)
-#define GICD_CHIPR_VALUE(chip_addr, spi_block_min, spi_blocks) \
+#define GICD_CHIPR_VALUE_GIC_700(chip_addr, spi_block_min, spi_blocks) \
+			(((chip_addr) << GICD_CHIPRx_ADDR_SHIFT) | \
+			((spi_block_min) << GIC_700_SPI_BLOCK_MIN_SHIFT) | \
+			((spi_blocks) << GIC_700_SPI_BLOCKS_SHIFT))
+#define GICD_CHIPR_VALUE_GIC_600(chip_addr, spi_block_min, spi_blocks) \
 			(((chip_addr) << GICD_CHIPRx_ADDR_SHIFT) | \
-			((spi_block_min) << GICD_CHIPRx_SPI_BLOCK_MIN_SHIFT) | \
-			((spi_blocks) << GICD_CHIPRx_SPI_BLOCKS_SHIFT))
+			((spi_block_min) << GIC_600_SPI_BLOCK_MIN_SHIFT) | \
+			((spi_blocks) << GIC_600_SPI_BLOCKS_SHIFT))
 
 /*
  * Multichip data assertion macros