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fsi/scom: Add mutex around FSI2PIB accesses

PATCH New Benjamin Herrenschmidt 1 participant 3 messages May 22, 2018 FSI

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Benjamin Herrenschmidt

author
#0 lore raw

PATCH 1/3 fsi/scom: Add mutex around FSI2PIB accesses

Otherwise, multiple clients can open the driver and attempt to access the PIB at the same time, thus clobbering each other in the process.

Signed-off-by Benjamin Herrenschmidt <[email protected]>
---
 drivers/fsi/fsi-scom.c | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)
drivers/fsi/fsi-scom.c +18 -7
index c8eb5e5b94a7..3cba0eb645e1 100644
@@ -37,6 +37,7 @@ struct scom_device {
 	struct list_head link;
 	struct fsi_device *fsi_dev;
 	struct miscdevice mdev;
+	struct mutex lock;
 	char	name[32];
 	int idx;
 };

@@ -53,21 +54,26 @@ static int put_scom(struct scom_device *scom_dev, uint64_t value,
 	int rc;
 	uint32_t data;
 
+	mutex_lock(&scom_dev->lock);
+
 	data = cpu_to_be32((value >> 32) & 0xffffffff);
 	rc = fsi_device_write(scom_dev->fsi_dev, SCOM_DATA0_REG, &data,
 				sizeof(uint32_t));
 	if (rc)
-		return rc;
+		goto bail;
 
 	data = cpu_to_be32(value & 0xffffffff);
 	rc = fsi_device_write(scom_dev->fsi_dev, SCOM_DATA1_REG, &data,
 				sizeof(uint32_t));
 	if (rc)
-		return rc;
+		goto bail;
 
 	data = cpu_to_be32(SCOM_WRITE_CMD | addr);
-	return fsi_device_write(scom_dev->fsi_dev, SCOM_CMD_REG, &data,
+	rc = fsi_device_write(scom_dev->fsi_dev, SCOM_CMD_REG, &data,
 				sizeof(uint32_t));
+ bail:
+	mutex_unlock(&scom_dev->lock);
+	return rc;
 }
 
 static int get_scom(struct scom_device *scom_dev, uint64_t *value,

@@ -76,27 +82,31 @@ static int get_scom(struct scom_device *scom_dev, uint64_t *value,
 	uint32_t result, data;
 	int rc;
 
+
+	mutex_lock(&scom_dev->lock);
 	*value = 0ULL;
 	data = cpu_to_be32(addr);
 	rc = fsi_device_write(scom_dev->fsi_dev, SCOM_CMD_REG, &data,
 				sizeof(uint32_t));
 	if (rc)
-		return rc;
+		goto bail;
 
 	rc = fsi_device_read(scom_dev->fsi_dev, SCOM_DATA0_REG, &result,
 				sizeof(uint32_t));
 	if (rc)
-		return rc;
+		goto bail;
 
 	*value |= (uint64_t)cpu_to_be32(result) << 32;
 	rc = fsi_device_read(scom_dev->fsi_dev, SCOM_DATA1_REG, &result,
 				sizeof(uint32_t));
 	if (rc)
-		return rc;
+		goto bail;
 
 	*value |= cpu_to_be32(result);
 
-	return 0;
+ bail:
+	mutex_unlock(&scom_dev->lock);
+	return rc;
 }
 
 static ssize_t scom_read(struct file *filep, char __user *buf, size_t len,

@@ -183,6 +193,7 @@ static int scom_probe(struct device *dev)
 	if (!scom)
 		return -ENOMEM;
 
+	mutex_init(&scom->lock);
 	scom->idx = ida_simple_get(&scom_ida, 1, INT_MAX, GFP_KERNEL);
 	snprintf(scom->name, sizeof(scom->name), "scom%d", scom->idx);
 	scom->fsi_dev = fsi_dev;
Signature · 1 line
2.17.0
author
#1 lore raw

PATCH 2/3 fsi/scom: Whitespace fixes

No functional changes

Signed-off-by Benjamin Herrenschmidt <[email protected]>
---
 drivers/fsi/fsi-scom.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)
drivers/fsi/fsi-scom.c +4 -4
index 3cba0eb645e1..8a608db0aa07 100644
@@ -49,7 +49,7 @@ static struct list_head scom_devices;
 static DEFINE_IDA(scom_ida);
 
 static int put_scom(struct scom_device *scom_dev, uint64_t value,
-			uint32_t addr)
+		    uint32_t addr)
 {
 	int rc;
 	uint32_t data;

@@ -77,7 +77,7 @@ static int put_scom(struct scom_device *scom_dev, uint64_t value,
 }
 
 static int get_scom(struct scom_device *scom_dev, uint64_t *value,
-			uint32_t addr)
+		    uint32_t addr)
 {
 	uint32_t result, data;
 	int rc;

@@ -110,7 +110,7 @@ static int get_scom(struct scom_device *scom_dev, uint64_t *value,
 }
 
 static ssize_t scom_read(struct file *filep, char __user *buf, size_t len,
-			loff_t *offset)
+			 loff_t *offset)
 {
 	int rc;
 	struct miscdevice *mdev =

@@ -136,7 +136,7 @@ static ssize_t scom_read(struct file *filep, char __user *buf, size_t len,
 }
 
 static ssize_t scom_write(struct file *filep, const char __user *buf,
-			size_t len, loff_t *offset)
+			  size_t len, loff_t *offset)
 {
 	int rc;
 	struct miscdevice *mdev = filep->private_data;
Signature · 1 line
2.17.0
author
#2 lore raw

PATCH 3/3 fsi/scom: Fixup endian annotations

In reply to Benjamin Herrenschmidt

Use the proper annotated type __be32 and fixup the accessor used for get_scom()

Signed-off-by Benjamin Herrenschmidt <[email protected]>
---
 drivers/fsi/fsi-scom.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)
drivers/fsi/fsi-scom.c +4 -5
index 8a608db0aa07..6ddfb6021420 100644
@@ -51,8 +51,8 @@ static DEFINE_IDA(scom_ida);
 static int put_scom(struct scom_device *scom_dev, uint64_t value,
 		    uint32_t addr)
 {
+	__be32 data;
 	int rc;
-	uint32_t data;
 
 	mutex_lock(&scom_dev->lock);
 

@@ -79,7 +79,7 @@ static int put_scom(struct scom_device *scom_dev, uint64_t value,
 static int get_scom(struct scom_device *scom_dev, uint64_t *value,
 		    uint32_t addr)
 {
-	uint32_t result, data;
+	__be32 result, data;
 	int rc;
 
 

@@ -96,14 +96,13 @@ static int get_scom(struct scom_device *scom_dev, uint64_t *value,
 	if (rc)
 		goto bail;
 
-	*value |= (uint64_t)cpu_to_be32(result) << 32;
+	*value |= (uint64_t)be32_to_cpu(result) << 32;
 	rc = fsi_device_read(scom_dev->fsi_dev, SCOM_DATA1_REG, &result,
 				sizeof(uint32_t));
 	if (rc)
 		goto bail;
 
-	*value |= cpu_to_be32(result);
-
+	*value |= be32_to_cpu(result);
  bail:
 	mutex_unlock(&scom_dev->lock);
 	return rc;
Signature · 1 line
2.17.0