Merge tag 'fsi-for-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/joel/fsi into char-misc-next

Joel writes:

FSI changes for v5.16

 - SBEFIFO usersapce interfaces to perform FFDC (First Failure
   Data Capture) and detect timeouts

 - A fix to handle multiple messages in flight

* tag 'fsi-for-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/joel/fsi:
  fsi: sbefifo: Use interruptible mutex locking
  fsi: sbefifo: Add sysfs file indicating a timeout error
  docs: ABI: testing: Document the SBEFIFO timeout interface
  hwmon: (occ) Provide the SBEFIFO FFDC in binary sysfs
  docs: ABI: testing: Document the OCC hwmon FFDC binary interface
  fsi: occ: Store the SBEFIFO FFDC in the user response buffer
  fsi: occ: Use a large buffer for responses
  hwmon: (occ) Remove sequence numbering and checksum calculation
  fsi: occ: Force sequence numbering per OCC

4 files changed, 109 insertions, 29 deletions

diff --git a/drivers/hwmon/occ/common.c b/drivers/hwmon/occ/common.c
index ae664613289c..0cb4a0a6cbc1 100644
--- a/drivers/hwmon/occ/common.c
+++ b/drivers/hwmon/occ/common.c
@@ -132,22 +132,20 @@ struct extended_sensor {
 static int occ_poll(struct occ *occ)
 {
 	int rc;
-	u16 checksum = occ->poll_cmd_data + occ->seq_no + 1;
-	u8 cmd[8];
+	u8 cmd[7];
 	struct occ_poll_response_header *header;
 
 	/* big endian */
-	cmd[0] = occ->seq_no++;		/* sequence number */
+	cmd[0] = 0;			/* sequence number */
 	cmd[1] = 0;			/* cmd type */
 	cmd[2] = 0;			/* data length msb */
 	cmd[3] = 1;			/* data length lsb */
 	cmd[4] = occ->poll_cmd_data;	/* data */
-	cmd[5] = checksum >> 8;		/* checksum msb */
-	cmd[6] = checksum & 0xFF;	/* checksum lsb */
-	cmd[7] = 0;
+	cmd[5] = 0;			/* checksum msb */
+	cmd[6] = 0;			/* checksum lsb */
 
 	/* mutex should already be locked if necessary */
-	rc = occ->send_cmd(occ, cmd);
+	rc = occ->send_cmd(occ, cmd, sizeof(cmd));
 	if (rc) {
 		occ->last_error = rc;
 		if (occ->error_count++ > OCC_ERROR_COUNT_THRESHOLD)
@@ -184,25 +182,23 @@ static int occ_set_user_power_cap(struct occ *occ, u16 user_power_cap)
 {
 	int rc;
 	u8 cmd[8];
-	u16 checksum = 0x24;
 	__be16 user_power_cap_be = cpu_to_be16(user_power_cap);
 
-	cmd[0] = 0;
-	cmd[1] = 0x22;
-	cmd[2] = 0;
-	cmd[3] = 2;
+	cmd[0] = 0;	/* sequence number */
+	cmd[1] = 0x22;	/* cmd type */
+	cmd[2] = 0;	/* data length msb */
+	cmd[3] = 2;	/* data length lsb */
 
 	memcpy(&cmd[4], &user_power_cap_be, 2);
 
-	checksum += cmd[4] + cmd[5];
-	cmd[6] = checksum >> 8;
-	cmd[7] = checksum & 0xFF;
+	cmd[6] = 0;	/* checksum msb */
+	cmd[7] = 0;	/* checksum lsb */
 
 	rc = mutex_lock_interruptible(&occ->lock);
 	if (rc)
 		return rc;
 
-	rc = occ->send_cmd(occ, cmd);
+	rc = occ->send_cmd(occ, cmd, sizeof(cmd));
 
 	mutex_unlock(&occ->lock);
 
@@ -1144,8 +1140,6 @@ int occ_setup(struct occ *occ, const char *name)
 {
 	int rc;
 
-	/* start with 1 to avoid false match with zero-initialized SRAM buffer */
-	occ->seq_no = 1;
 	mutex_init(&occ->lock);
 	occ->groups[0] = &occ->group;
 
diff --git a/drivers/hwmon/occ/common.h b/drivers/hwmon/occ/common.h
index e6df719770e8..5020117be740 100644
--- a/drivers/hwmon/occ/common.h
+++ b/drivers/hwmon/occ/common.h
@@ -95,9 +95,8 @@ struct occ {
 	struct occ_sensors sensors;
 
 	int powr_sample_time_us;	/* average power sample time */
-	u8 seq_no;
 	u8 poll_cmd_data;		/* to perform OCC poll command */
-	int (*send_cmd)(struct occ *occ, u8 *cmd);
+	int (*send_cmd)(struct occ *occ, u8 *cmd, size_t len);
 
 	unsigned long next_update;
 	struct mutex lock;		/* lock OCC access */
diff --git a/drivers/hwmon/occ/p8_i2c.c b/drivers/hwmon/occ/p8_i2c.c
index 0cf8588be35a..9e61e1fb5142 100644
--- a/drivers/hwmon/occ/p8_i2c.c
+++ b/drivers/hwmon/occ/p8_i2c.c
@@ -97,18 +97,21 @@ static int p8_i2c_occ_putscom_u32(struct i2c_client *client, u32 address,
 }
 
 static int p8_i2c_occ_putscom_be(struct i2c_client *client, u32 address,
-				 u8 *data)
+				 u8 *data, size_t len)
 {
-	__be32 data0, data1;
+	__be32 data0 = 0, data1 = 0;
 
-	memcpy(&data0, data, 4);
-	memcpy(&data1, data + 4, 4);
+	memcpy(&data0, data, min_t(size_t, len, 4));
+	if (len > 4) {
+		len -= 4;
+		memcpy(&data1, data + 4, min_t(size_t, len, 4));
+	}
 
 	return p8_i2c_occ_putscom_u32(client, address, be32_to_cpu(data0),
 				      be32_to_cpu(data1));
 }
 
-static int p8_i2c_occ_send_cmd(struct occ *occ, u8 *cmd)
+static int p8_i2c_occ_send_cmd(struct occ *occ, u8 *cmd, size_t len)
 {
 	int i, rc;
 	unsigned long start;
@@ -127,7 +130,7 @@ static int p8_i2c_occ_send_cmd(struct occ *occ, u8 *cmd)
 		return rc;
 
 	/* write command (expected to already be BE), we need bus-endian... */
-	rc = p8_i2c_occ_putscom_be(client, OCB_DATA3, cmd);
+	rc = p8_i2c_occ_putscom_be(client, OCB_DATA3, cmd, len);
 	if (rc)
 		return rc;
 
diff --git a/drivers/hwmon/occ/p9_sbe.c b/drivers/hwmon/occ/p9_sbe.c
index f6387cc0b754..e50243580269 100644
--- a/drivers/hwmon/occ/p9_sbe.c
+++ b/drivers/hwmon/occ/p9_sbe.c
@@ -4,28 +4,96 @@
 #include <linux/device.h>
 #include <linux/errno.h>
 #include <linux/fsi-occ.h>
+#include <linux/mm.h>
 #include <linux/module.h>
+#include <linux/mutex.h>
 #include <linux/platform_device.h>
+#include <linux/string.h>
+#include <linux/sysfs.h>
 
 #include "common.h"
 
 struct p9_sbe_occ {
 	struct occ occ;
+	bool sbe_error;
+	void *ffdc;
+	size_t ffdc_len;
+	size_t ffdc_size;
+	struct mutex sbe_error_lock;	/* lock access to ffdc data */
 	struct device *sbe;
 };
 
 #define to_p9_sbe_occ(x)	container_of((x), struct p9_sbe_occ, occ)
 
-static int p9_sbe_occ_send_cmd(struct occ *occ, u8 *cmd)
+static ssize_t ffdc_read(struct file *filp, struct kobject *kobj,
+			 struct bin_attribute *battr, char *buf, loff_t pos,
+			 size_t count)
+{
+	ssize_t rc = 0;
+	struct occ *occ = dev_get_drvdata(kobj_to_dev(kobj));
+	struct p9_sbe_occ *ctx = to_p9_sbe_occ(occ);
+
+	mutex_lock(&ctx->sbe_error_lock);
+	if (ctx->sbe_error) {
+		rc = memory_read_from_buffer(buf, count, &pos, ctx->ffdc,
+					     ctx->ffdc_len);
+		if (pos >= ctx->ffdc_len)
+			ctx->sbe_error = false;
+	}
+	mutex_unlock(&ctx->sbe_error_lock);
+
+	return rc;
+}
+static BIN_ATTR_RO(ffdc, OCC_MAX_RESP_WORDS * 4);
+
+static bool p9_sbe_occ_save_ffdc(struct p9_sbe_occ *ctx, const void *resp,
+				 size_t resp_len)
+{
+	bool notify = false;
+
+	mutex_lock(&ctx->sbe_error_lock);
+	if (!ctx->sbe_error) {
+		if (resp_len > ctx->ffdc_size) {
+			if (ctx->ffdc)
+				kvfree(ctx->ffdc);
+			ctx->ffdc = kvmalloc(resp_len, GFP_KERNEL);
+			if (!ctx->ffdc) {
+				ctx->ffdc_len = 0;
+				ctx->ffdc_size = 0;
+				goto done;
+			}
+
+			ctx->ffdc_size = resp_len;
+		}
+
+		notify = true;
+		ctx->sbe_error = true;
+		ctx->ffdc_len = resp_len;
+		memcpy(ctx->ffdc, resp, resp_len);
+	}
+
+done:
+	mutex_unlock(&ctx->sbe_error_lock);
+	return notify;
+}
+
+static int p9_sbe_occ_send_cmd(struct occ *occ, u8 *cmd, size_t len)
 {
 	struct occ_response *resp = &occ->resp;
 	struct p9_sbe_occ *ctx = to_p9_sbe_occ(occ);
 	size_t resp_len = sizeof(*resp);
 	int rc;
 
-	rc = fsi_occ_submit(ctx->sbe, cmd, 8, resp, &resp_len);
-	if (rc < 0)
+	rc = fsi_occ_submit(ctx->sbe, cmd, len, resp, &resp_len);
+	if (rc < 0) {
+		if (resp_len) {
+			if (p9_sbe_occ_save_ffdc(ctx, resp, resp_len))
+				sysfs_notify(&occ->bus_dev->kobj, NULL,
+					     bin_attr_ffdc.attr.name);
+		}
+
 		return rc;
+	}
 
 	switch (resp->return_status) {
 	case OCC_RESP_CMD_IN_PRG:
@@ -65,6 +133,8 @@ static int p9_sbe_occ_probe(struct platform_device *pdev)
 	if (!ctx)
 		return -ENOMEM;
 
+	mutex_init(&ctx->sbe_error_lock);
+
 	ctx->sbe = pdev->dev.parent;
 	occ = &ctx->occ;
 	occ->bus_dev = &pdev->dev;
@@ -78,6 +148,15 @@ static int p9_sbe_occ_probe(struct platform_device *pdev)
 	if (rc == -ESHUTDOWN)
 		rc = -ENODEV;	/* Host is shutdown, don't spew errors */
 
+	if (!rc) {
+		rc = device_create_bin_file(occ->bus_dev, &bin_attr_ffdc);
+		if (rc) {
+			dev_warn(occ->bus_dev,
+				 "failed to create SBE error ffdc file\n");
+			rc = 0;
+		}
+	}
+
 	return rc;
 }
 
@@ -86,9 +165,14 @@ static int p9_sbe_occ_remove(struct platform_device *pdev)
 	struct occ *occ = platform_get_drvdata(pdev);
 	struct p9_sbe_occ *ctx = to_p9_sbe_occ(occ);
 
+	device_remove_bin_file(occ->bus_dev, &bin_attr_ffdc);
+
 	ctx->sbe = NULL;
 	occ_shutdown(occ);
 
+	if (ctx->ffdc)
+		kvfree(ctx->ffdc);
+
 	return 0;
 }