RAS: SGI: Add platform handler for RAS interrupts

Add a platform specific handler for RAS interrupts and configure the
platform RAS interrupts for EL3 handling. The interrupt handler passes
control to StandaloneMM code executing in S-EL0, which populates the
CPER buffer with relevant error information. The handler subsequently
invokes the SDEI client which processes the information in the error
information in the CPER buffer. The helper functions
plat_sgi_get_ras_ev_map and plat_sgi_get_ras_ev_map_size would be
defined for sgi platforms in the subsequent patch, which adds sgi575
specific RAS changes.

Change-Id: I490f16c15d9917ac40bdc0441659b92380108d63
Signed-off-by: Sughosh Ganu <sughosh.ganu@arm.com>
diff --git a/plat/arm/css/sgi/sgi_ras.c b/plat/arm/css/sgi/sgi_ras.c
new file mode 100644
index 0000000..60c402f
--- /dev/null
+++ b/plat/arm/css/sgi/sgi_ras.c
@@ -0,0 +1,132 @@
+/*
+ * Copyright (c) 2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <arm_spm_def.h>
+#include <assert.h>
+#include <context_mgmt.h>
+#include <interrupt_mgmt.h>
+#include <mm_svc.h>
+#include <ras.h>
+#include <sgi_ras.h>
+#include <platform.h>
+#include <spm_svc.h>
+#include <sdei.h>
+#include <string.h>
+
+static int sgi_ras_intr_handler(const struct err_record_info *err_rec,
+				int probe_data,
+				const struct err_handler_data *const data);
+struct efi_guid {
+	uint32_t	data1;
+	uint16_t	data2;
+	uint16_t	data3;
+	uint8_t		data4[8];
+};
+
+typedef struct mm_communicate_header {
+	struct efi_guid	header_guid;
+	size_t		message_len;
+	uint8_t		data[8];
+} mm_communicate_header_t;
+
+/*
+ * Find event mapping for a given interrupt number: On success, returns pointer
+ * to the event mapping. On error, returns NULL.
+ */
+static struct sgi_ras_ev_map *find_ras_event_map_by_intr(uint32_t intr_num)
+{
+	struct sgi_ras_ev_map *map = plat_sgi_get_ras_ev_map();
+	int i;
+	int size = plat_sgi_get_ras_ev_map_size();
+
+	for (i = 0; i < size; i++) {
+		if (map->intr == intr_num)
+			return map;
+
+		map++;
+	}
+
+	return NULL;
+}
+
+static void sgi_ras_intr_configure(int intr)
+{
+	plat_ic_set_interrupt_type(intr, INTR_TYPE_EL3);
+	plat_ic_set_interrupt_priority(intr, PLAT_RAS_PRI);
+	plat_ic_clear_interrupt_pending(intr);
+	plat_ic_set_spi_routing(intr, INTR_ROUTING_MODE_ANY,
+				(u_register_t)read_mpidr_el1());
+	plat_ic_enable_interrupt(intr);
+}
+
+static int sgi_ras_intr_handler(const struct err_record_info *err_rec,
+				int probe_data,
+				const struct err_handler_data *const data)
+{
+	struct sgi_ras_ev_map *ras_map;
+	mm_communicate_header_t *header;
+	uint32_t intr;
+
+	cm_el1_sysregs_context_save(NON_SECURE);
+	intr = data->interrupt;
+
+	/*
+	 * Find if this is a RAS interrupt. There must be an event against
+	 * this interrupt
+	 */
+	ras_map = find_ras_event_map_by_intr(intr);
+	assert(ras_map);
+
+	/*
+	 * Populate the MM_COMMUNICATE payload to share the
+	 * event info with StandaloneMM code. This allows us to use
+	 * MM_COMMUNICATE as a common entry mechanism into S-EL0. The
+	 * header data will be parsed in StandaloneMM to process the
+	 * corresponding event.
+	 *
+	 * TBD - Currently, the buffer allocated by SPM for communication
+	 * between EL3 and S-EL0 is being used(PLAT_SPM_BUF_BASE). But this
+	 * should happen via a dynamic mem allocation, which should be
+	 * managed by SPM -- the individual platforms then call the mem
+	 * alloc api to get memory for the payload.
+	 */
+	header = (void *) PLAT_SPM_BUF_BASE;
+	memset(header, 0, sizeof(*header));
+	memcpy(&header->data, &ras_map->ras_ev_num,
+	       sizeof(ras_map->ras_ev_num));
+	header->message_len = 4;
+
+	spm_sp_call(MM_COMMUNICATE_AARCH64, (uint64_t)header, 0,
+		    plat_my_core_pos());
+
+	/*
+	 * Do an EOI of the RAS interuupt. This allows the
+	 * sdei event to be dispatched at the SDEI event's
+	 * priority.
+	 */
+	plat_ic_end_of_interrupt(intr);
+
+	/* Dispatch the event to the SDEI client */
+	sdei_dispatch_event(ras_map->sdei_ev_num);
+
+	return 0;
+}
+
+int sgi_ras_intr_handler_setup(void)
+{
+	int i;
+	struct sgi_ras_ev_map *map = plat_sgi_get_ras_ev_map();
+	int size = plat_sgi_get_ras_ev_map_size();
+
+	for (i = 0; i < size; i++) {
+		sgi_ras_intr_configure(map->intr);
+		map++;
+	}
+
+	INFO("SGI: RAS Interrupt Handler successfully registered\n");
+
+	return 0;
+}