[PATCH] ASoC: cs-amp-lib: Ignore empty UEFI calibration entries

[Richard Fitzgerald <rf@opensource.cirrus.com>]

If the timestamp of a calibration entry is 0 it is an unused entry and
must be ignored.

Some end-products reserve EFI space for calibration entries by shipping
with a zero-filled EFI file. When searching the file for calibration
data the driver must skip the empty entries. The timestamp of a valid
entry is always non-zero.

The type of struct cirrus_amp_efi_data.calTime has been changed from an
array of two u32 to a single u64. The timestamp is a 64-bit value and
treating it as such simplifies the code.

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Fixes: 1cad8725f2b9 ("ASoC: cs-amp-lib: Add helpers for factory calibration data")
---
 include/sound/cs-amp-lib.h    | 2 +-
 sound/soc/codecs/cs-amp-lib.c | 7 ++++++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/include/sound/cs-amp-lib.h b/include/sound/cs-amp-lib.h
index f481148735e1..77c4c1c9cf1a 100644
--- a/include/sound/cs-amp-lib.h
+++ b/include/sound/cs-amp-lib.h
@@ -14,7 +14,7 @@ struct cs_dsp;
 
 struct cirrus_amp_cal_data {
 	u32 calTarget[2];
-	u32 calTime[2];
+	u64 calTime;
 	s8  calAmbient;
 	u8  calStatus;
 	u16 calR;
diff --git a/sound/soc/codecs/cs-amp-lib.c b/sound/soc/codecs/cs-amp-lib.c
index 605964af8afa..8aaca88ef1b6 100644
--- a/sound/soc/codecs/cs-amp-lib.c
+++ b/sound/soc/codecs/cs-amp-lib.c
@@ -182,6 +182,10 @@ static int _cs_amp_get_efi_calibration_data(struct device *dev, u64 target_uid,
 		for (i = 0; i < efi_data->count; ++i) {
 			u64 cal_target = cs_amp_cal_target_u64(&efi_data->data[i]);
 
+			/* Skip empty entries */
+			if (efi_data->data[i].calTime == 0)
+				continue;
+
 			/* Skip entries with unpopulated silicon ID */
 			if (cal_target == 0)
 				continue;
@@ -193,7 +197,8 @@ static int _cs_amp_get_efi_calibration_data(struct device *dev, u64 target_uid,
 		}
 	}
 
-	if (!cal && (amp_index >= 0) && (amp_index < efi_data->count)) {
+	if (!cal && (amp_index >= 0) && (amp_index < efi_data->count) &&
+	    (efi_data->data[amp_index].calTime != 0)) {
 		u64 cal_target = cs_amp_cal_target_u64(&efi_data->data[amp_index]);
 
 		/*
-- 
2.39.2