[PATCH v5 3/6] spmi: apple: check transaction status

[Sasha Finkelstein]

From: Alba Mendez <me at alba.sh>

Check for parity errors and missing command ACKs.

Signed-off-by: Alba Mendez <me at alba.sh>
Reviewed-by: Janne Grunau <j at jannau.net>
Signed-off-by: Sasha Finkelstein <k at chaosmail.tech>
---
 drivers/spmi/spmi-apple-controller.c | 25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/drivers/spmi/spmi-apple-controller.c b/drivers/spmi/spmi-apple-controller.c
index 15721cb41d5c..b1c127cf5f44 100644
--- a/drivers/spmi/spmi-apple-controller.c
+++ b/drivers/spmi/spmi-apple-controller.c
@@ -11,6 +11,8 @@
  *		spmi-pmic-arb.c Copyright (c) 2021, The Linux Foundation.
  */
 
+#include <linux/bitfield.h>
+#include <linux/bits.h>
 #include <linux/io.h>
 #include <linux/iopoll.h>
 #include <linux/module.h>
@@ -23,6 +25,12 @@
 #define SPMI_RSP_REG 0x8
 #define SPMI_ACT_REG 0xa4
 
+/* SPMI_RSP_REG reply word */
+#define SPMI_REPLY_FRAME_PARITY_STATUS GENMASK(31, 16)
+#define SPMI_REPLY_ACK BIT(15)
+#define SPMI_REPLY_SLAVE_ID GENMASK(14, 8)
+#define SPMI_REPLY_CMD GENMASK(7, 0)
+
 #define SPMI_ACT_FIFO_FLUSH BIT(0)
 #define SPMI_RX_FIFO_EMPTY BIT(24)
 
@@ -66,7 +74,7 @@ static int spmi_read_cmd(struct spmi_controller *ctrl, u8 opc, u8 sid,
 {
 	struct apple_spmi *spmi = spmi_controller_get_drvdata(ctrl);
 	u32 spmi_cmd = apple_spmi_pack_cmd(opc, sid, saddr, len);
-	u32 rsp;
+	u32 reply, rsp;
 	size_t len_read = 0;
 	u8 i;
 	int ret;
@@ -82,8 +90,7 @@ static int spmi_read_cmd(struct spmi_controller *ctrl, u8 opc, u8 sid,
 	if (ret)
 		return ret;
 
-	/* Discard SPMI reply status */
-	readl(spmi->regs + SPMI_RSP_REG);
+	reply = readl(spmi->regs + SPMI_RSP_REG);
 
 	/* Read SPMI data reply */
 	while (len_read < len) {
@@ -106,6 +113,10 @@ static int spmi_read_cmd(struct spmi_controller *ctrl, u8 opc, u8 sid,
 		spmi->prev_fail = true;
 	}
 
+	if (~FIELD_GET(SPMI_REPLY_FRAME_PARITY_STATUS, reply) & ((1 << len) - 1)) {
+		dev_err(&ctrl->dev, "some frames failed parity check\n");
+		return -EIO;
+	}
 	return 0;
 }
 
@@ -114,6 +125,7 @@ static int spmi_write_cmd(struct spmi_controller *ctrl, u8 opc, u8 sid,
 {
 	struct apple_spmi *spmi = spmi_controller_get_drvdata(ctrl);
 	u32 spmi_cmd = apple_spmi_pack_cmd(opc, sid, saddr, len);
+	u32 reply;
 	size_t i = 0, j;
 	int ret;
 
@@ -137,14 +149,17 @@ static int spmi_write_cmd(struct spmi_controller *ctrl, u8 opc, u8 sid,
 	if (ret)
 		return ret;
 
-	/* Discard */
-	readl(spmi->regs + SPMI_RSP_REG);
+	reply = readl(spmi->regs + SPMI_RSP_REG);
 
 	if (!(readl(spmi->regs + SPMI_STATUS_REG) & SPMI_RX_FIFO_EMPTY)) {
 		dev_warn(&ctrl->dev, "FIFO has extra data\n");
 		spmi->prev_fail = true;
 	}
 
+	if (!FIELD_GET(SPMI_REPLY_ACK, reply)) {
+		dev_err(&ctrl->dev, "command not acknowledged\n");
+		return -EIO;
+	}
 	return 0;
 }
 

-- 
2.55.0