cper: add timestamp print to CPER status printing

The ACPI 6.1 spec added a timestamp to the generic error data
entry structure. Print the timestamp out when printing out the
error information.
Signed-off-by: Tyler Baicar <tbaicar@codeaurora.org>
CC: Jonathan (Zhixiong) Zhang <zjzhang@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

drivers/firmware/efi/cper.c

@@ -32,6 +32,8 @@
 #include <linux/acpi.h>
 #include <linux/pci.h>
 #include <linux/aer.h>
+#include <linux/printk.h>
+#include <linux/bcd.h>
 #include <acpi/ghes.h>
 
 #define INDENT_SP	" "
@@ -387,6 +389,27 @@ static void cper_print_pcie(const char *pfx, const struct cper_sec_pcie *pcie,
 	pfx, pcie->bridge.secondary_status, pcie->bridge.control);
 }
 
+static void cper_print_tstamp(const char *pfx,
+				   struct acpi_hest_generic_data_v300 *gdata)
+{
+	__u8 hour, min, sec, day, mon, year, century, *timestamp;
+
+	if (gdata->validation_bits & ACPI_HEST_GEN_VALID_TIMESTAMP) {
+		timestamp = (__u8 *)&(gdata->time_stamp);
+		sec       = bcd2bin(timestamp[0]);
+		min       = bcd2bin(timestamp[1]);
+		hour      = bcd2bin(timestamp[2]);
+		day       = bcd2bin(timestamp[4]);
+		mon       = bcd2bin(timestamp[5]);
+		year      = bcd2bin(timestamp[6]);
+		century   = bcd2bin(timestamp[7]);
+
+		printk("%s%ststamp: %02d%02d-%02d-%02d %02d:%02d:%02d\n", pfx,
+		       (timestamp[3] & 0x1 ? "precise " : "imprecise "),
+		       century, year, mon, day, hour, min, sec);
+	}
+}
+
 static void
 cper_estatus_print_section(const char *pfx, struct acpi_hest_generic_data *gdata,
 			   int sec_no)
@@ -395,6 +418,9 @@ cper_estatus_print_section(const char *pfx, struct acpi_hest_generic_data *gdata
 	__u16 severity;
 	char newpfx[64];
 
+	if (acpi_hest_get_version(gdata) >= 3)
+		cper_print_tstamp(pfx, (struct acpi_hest_generic_data_v300 *)gdata);
+
 	severity = gdata->error_severity;
 	printk("%s""Error %d, type: %s\n", pfx, sec_no,
 	       cper_severity_str(severity));