ACPI: APEI: Use ERST timeout for slow devices

Slow devices such as flash may not meet the default 1ms timeout value,
so use the ERST max execution time value that they provide as the
timeout if it is larger.

Signed-off-by: Jeshua Smith <[e-mail]>
Reviewed-by: Tony Luck <[e-mail]>
Signed-off-by: Rafael J. Wysocki <[e-mail]>

drivers/acpi/apei/erst.c

···
 #define ERST_RANGE_NVRAM	0x0002
 #define ERST_RANGE_SLOW		0x0004
 
+/* ERST Exec max timings */
+#define ERST_EXEC_TIMING_MAX_MASK      0xFFFFFFFF00000000
+#define ERST_EXEC_TIMING_MAX_SHIFT     32
+
 /*
  * ERST Error Log Address Range, used as buffer for reading/writing
  * error records.
···
 	u64 size;
 	void __iomem *vaddr;
 	u32 attr;
+	u64 timings;
 } erst_erange;
 
 /*
···
 	default:
 		return -EINVAL;
 	}
+}
+
+static inline u64 erst_get_timeout(void)
+{
+	u64 timeout = FIRMWARE_TIMEOUT;
+
+	if (erst_erange.attr & ERST_RANGE_SLOW) {
+		timeout = ((erst_erange.timings & ERST_EXEC_TIMING_MAX_MASK) >>
+			ERST_EXEC_TIMING_MAX_SHIFT) * NSEC_PER_MSEC;
+		if (timeout < FIRMWARE_TIMEOUT)
+			timeout = FIRMWARE_TIMEOUT;
+	}
+	return timeout;
 }
 
 static int erst_timedout(u64 *t, u64 spin_unit)
···
 {
 	int rc;
 	u64 val;
-	u64 timeout = FIRMWARE_TIMEOUT;
+	u64 timeout;
 	u64 stall_time;
+
+	timeout = erst_get_timeout();
 
 	if (ctx->var1 > FIRMWARE_MAX_STALL) {
 		if (!in_nmi())
···
 	if (rc)
 		return rc;
 	range->attr = apei_exec_ctx_get_output(&ctx);
+	rc = apei_exec_run(&ctx, ACPI_ERST_EXECUTE_TIMINGS);
+	if (rc == 0)
+		range->timings = apei_exec_ctx_get_output(&ctx);
+	else if (rc == -ENOENT)
+		range->timings = 0;
+	else
+		return rc;
 
 	return 0;
 }
···
 static int __erst_write_to_storage(u64 offset)
 {
 	struct apei_exec_context ctx;
-	u64 timeout = FIRMWARE_TIMEOUT;
+	u64 timeout;
 	u64 val;
 	int rc;
+
+	timeout = erst_get_timeout();
 
 	erst_exec_ctx_init(&ctx);
 	rc = apei_exec_run_optional(&ctx, ACPI_ERST_BEGIN_WRITE);
···
 static int __erst_read_from_storage(u64 record_id, u64 offset)
 {
 	struct apei_exec_context ctx;
-	u64 timeout = FIRMWARE_TIMEOUT;
+	u64 timeout;
 	u64 val;
 	int rc;
+
+	timeout = erst_get_timeout();
 
 	erst_exec_ctx_init(&ctx);
 	rc = apei_exec_run_optional(&ctx, ACPI_ERST_BEGIN_READ);
···
 static int __erst_clear_from_storage(u64 record_id)
 {
 	struct apei_exec_context ctx;
-	u64 timeout = FIRMWARE_TIMEOUT;
+	u64 timeout;
 	u64 val;
 	int rc;
+
+	timeout = erst_get_timeout();
 
 	erst_exec_ctx_init(&ctx);
 	rc = apei_exec_run_optional(&ctx, ACPI_ERST_BEGIN_CLEAR);