RAS: Add helpers to access Standard Error Records

The ARMv8 RAS Extensions introduced Standard Error Records which are a
set of standard registers through which:

  - Platform can configure RAS node policy; e.g., notification
    mechanism;

  - RAS nodes can record and expose error information for error handling
    agents.

Standard Error Records can either be accessed via. memory-mapped
or System registers. This patch adds helper functions to access
registers and fields within an error record.

Change-Id: I6594ba799f4a1789d7b1e45b3e17fd40e7e0ba5c
Signed-off-by: Jeenu Viswambharan <jeenu.viswambharan@arm.com>

1 files changed, 76 insertions, 0 deletions

diff --git a/lib/extensions/ras/std_err_record.c b/lib/extensions/ras/std_err_record.c
new file mode 100644
index 000000000..65c007f9e
--- /dev/null
+++ b/lib/extensions/ras/std_err_record.c
@@ -0,0 +1,76 @@
+/*
+ * Copyright (c) 2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+#include <ras_arch.h>
+#include <utils_def.h>
+
+/*
+ * Probe for error in memory-mapped registers containing error records
+ * implemented Standard Error Record format. Upon detecting an error, set probe
+ * data to the index of the record in error, and return 1; otherwise, return 0.
+ */
+int ser_probe_memmap(uintptr_t base, unsigned int size_num_k, int *probe_data)
+{
+	int num_records, num_group_regs, i;
+	uint64_t gsr;
+
+	assert(base != 0);
+
+	/* Only 4K supported for now */
+	assert(size_num_k == STD_ERR_NODE_SIZE_NUM_K);
+
+	num_records = (mmio_read_32(ERR_DEVID(base, size_num_k)) & ERR_DEVID_MASK);
+
+	/* A group register shows error status for 2^6 error records */
+	num_group_regs = (num_records >> 6) + 1;
+
+	/* Iterate through group registers to find a record in error */
+	for (i = 0; i < num_group_regs; i++) {
+		gsr = mmio_read_64(ERR_GSR(base, size_num_k, i));
+		if (gsr == 0)
+			continue;
+
+		/* Return the index of the record in error */
+		if (probe_data != NULL)
+			*probe_data = ((i << 6) + __builtin_ctz(gsr));
+
+		return 1;
+	}
+
+	return 0;
+}
+
+/*
+ * Probe for error in System Registers where error records are implemented in
+ * Standard Error Record format. Upon detecting an error, set probe data to the
+ * index of the record in error, and return 1; otherwise, return 0.
+ */
+int ser_probe_sysreg(unsigned int idx_start, unsigned int num_idx, int *probe_data)
+{
+	int i;
+	uint64_t status;
+	unsigned int max_idx __unused = read_erridr_el1() & ERRIDR_MASK;
+
+	assert(idx_start < max_idx);
+	assert(check_u32_overflow(idx_start, num_idx) == 0);
+	assert((idx_start + num_idx - 1) < max_idx);
+
+	for (i = 0; i < num_idx; i++) {
+		/* Select the error record */
+		ser_sys_select_record(idx_start + i);
+
+		/* Retrieve status register from the error record */
+		status = read_erxstatus_el1();
+
+		/* Check for valid field in status */
+		if (ERR_STATUS_GET_FIELD(status, V)) {
+			if (probe_data != NULL)
+				*probe_data = i;
+			return 1;
+		}
+	}
+
+	return 0;
+}