Re: [RFC PATCH 1/5] fsi/scom: Add mutex around FSI2PIB accesses

2018-06-13 Thread Eddie James 




On 06/12/2018 12:19 AM, Benjamin Herrenschmidt wrote:

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 


Reviewed-by: Eddie James 


---
  drivers/fsi/fsi-scom.c | 25 ++---
  1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/drivers/fsi/fsi-scom.c b/drivers/fsi/fsi-scom.c
index c8eb5e5b94a7..3cba0eb645e1 100644
--- a/drivers/fsi/fsi-scom.c
+++ b/drivers/fsi/fsi-scom.c
@@ -37,6 +37,7 @@ struct scom_device {
struct list_head link;
struct fsi_device *fsi_dev;
struct miscdevice mdev;
+   struct mutex lock;
charname[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) & 0x);
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 & 0x);
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;

[RFC PATCH 1/5] fsi/scom: Add mutex around FSI2PIB accesses

2018-06-11 Thread Benjamin Herrenschmidt 
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 
---
 drivers/fsi/fsi-scom.c | 25 ++---
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/drivers/fsi/fsi-scom.c b/drivers/fsi/fsi-scom.c
index c8eb5e5b94a7..3cba0eb645e1 100644
--- a/drivers/fsi/fsi-scom.c
+++ b/drivers/fsi/fsi-scom.c
@@ -37,6 +37,7 @@ struct scom_device {
struct list_head link;
struct fsi_device *fsi_dev;
struct miscdevice mdev;
+   struct mutex lock;
charname[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) & 0x);
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 & 0x);
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;
-- 
2.17.0