[PATCH v4] misc: i2c_eeprom: consider pagesize when writing to eeprom

[Michel Alex]

Calculate the maximum length of the buffer when writing
across the page boundary. If the buffer length (len)
exceeds the page boundary (pagesize), split it. Use this
length instead of comparing the length with the pagesize,
because if the write start address (offset) is not at the
beginning of a page and the page_offset + len is greater
than the page boundary (pagesize), the write operation
would overflow the current page and the behaviour can be
undefined (e.g. at24).

Signed-off-by: Alex Michel 
---
Changes for v2:
- fixed deviations from checkpatch.pl
- improved commit message
Changes for v3:
- cleaned up brackets
Changes for v4:
 - use "int" instead of "unsigned int"
---
 drivers/misc/i2c_eeprom.c | 13 -
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/i2c_eeprom.c b/drivers/misc/i2c_eeprom.c
index bdd7e018cc..0d35efb7f7 100644
--- a/drivers/misc/i2c_eeprom.c
+++ b/drivers/misc/i2c_eeprom.c
@@ -60,6 +60,17 @@ static int i2c_eeprom_std_read(struct udevice *dev, int 
offset, uint8_t *buf,
return dm_i2c_read(dev, offset, buf, size);
 }
 
+static int i2c_eeprom_len(int offset, int len, int pagesize)
+{
+   int page_offset = offset & (pagesize - 1);
+   int maxlen = pagesize - page_offset;
+
+   if (len > maxlen)
+   len = maxlen;
+
+   return len;
+}
+
 static int i2c_eeprom_std_write(struct udevice *dev, int offset,
const uint8_t *buf, int size)
 {
@@ -67,7 +78,7 @@ static int i2c_eeprom_std_write(struct udevice *dev, int 
offset,
int ret;
 
while (size > 0) {
-   int write_size = min_t(int, size, priv->pagesize);
+   int write_size = i2c_eeprom_len(offset, size, priv->pagesize);
 
ret = dm_i2c_write(dev, offset, buf, write_size);
if (ret)
-- 
2.34.1

AW: [PATCH v2] misc: i2c_eeprom: consider pagesize when writing to eeprom

[Michel Alex]

Hi Tom,

> We don't need to promote the types to unsigned here do we?

You are right, I will provide a new version of my patch where I will change all 
"unsigned int" 's to int's.

Alex

[PATCH v3] misc: i2c_eeprom: consider pagesize when writing to eeprom

[Michel Alex]

Calculate the maximum length of the buffer when writing
across the page boundary. If the buffer length (len)
exceeds the page boundary (pagesize), split it. Use this
length instead of comparing the length with the pagesize,
because if the write start address (offset) is not at the
beginning of a page and the page_offset + len is greater
than the page boundary (pagesize), the write operation
would overflow the current page and the behaviour can be
undefined (e.g. at24).

Signed-off-by: Alex Michel 
---
Changes for v2:
- fixed deviations from checkpatch.pl
- improved commit message
Changes for v3:
- cleaned up brackets
---
 drivers/misc/i2c_eeprom.c | 13 -
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/i2c_eeprom.c b/drivers/misc/i2c_eeprom.c
index bdd7e018cc..947eeb5648 100644
--- a/drivers/misc/i2c_eeprom.c
+++ b/drivers/misc/i2c_eeprom.c
@@ -60,6 +60,17 @@ static int i2c_eeprom_std_read(struct udevice *dev, int 
offset, uint8_t *buf,
return dm_i2c_read(dev, offset, buf, size);
 }

+static int i2c_eeprom_len(unsigned int offset, unsigned int len, unsigned int 
pagesize)
+{
+   int page_offset = offset & (pagesize - 1);
+   unsigned int maxlen = pagesize - page_offset;
+
+   if (len > maxlen)
+   len = maxlen;
+
+   return len;
+}
+
 static int i2c_eeprom_std_write(struct udevice *dev, int offset,
const uint8_t *buf, int size)
 {
@@ -67,7 +78,7 @@ static int i2c_eeprom_std_write(struct udevice *dev, int 
offset,
int ret;

while (size > 0) {
-   int write_size = min_t(int, size, priv->pagesize);
+   int write_size = i2c_eeprom_len(offset, size, priv->pagesize);

ret = dm_i2c_write(dev, offset, buf, write_size);
if (ret)
--
2.34.1

[PATCH v2] misc: i2c_eeprom: consider pagesize when writing to eeprom

[Michel Alex]

Calculate the maximum length of the buffer when writing
across the page boundary. If the buffer length (len)
exceeds the page boundary (pagesize), split it. Use this
length instead of comparing the length with the pagesize,
because if the write start address (offset) is not at the
beginning of a page and the page_offset + len is greater
than the page boundary (pagesize), the write operation
would overflow the current page and the behaviour can be
undefined (e.g. at24).

Signed-off-by: Alex Michel 
---
Changes for v2:
- fixed deviations from checkpatch.pl
- improved commit message
---
 drivers/misc/i2c_eeprom.c | 13 -
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/i2c_eeprom.c b/drivers/misc/i2c_eeprom.c
index bdd7e018cc..0eecbd07ba 100644
--- a/drivers/misc/i2c_eeprom.c
+++ b/drivers/misc/i2c_eeprom.c
@@ -60,6 +60,17 @@ static int i2c_eeprom_std_read(struct udevice *dev, int 
offset, uint8_t *buf,
return dm_i2c_read(dev, offset, buf, size);
 }

+static int i2c_eeprom_len(unsigned int offset, unsigned int len, unsigned int 
pagesize)
+{
+   int page_offset = ((offset) & (pagesize - 1));
+   unsigned int maxlen = pagesize - page_offset;
+
+   if (len > maxlen)
+   len = maxlen;
+
+   return len;
+}
+
 static int i2c_eeprom_std_write(struct udevice *dev, int offset,
const uint8_t *buf, int size)
 {
@@ -67,7 +78,7 @@ static int i2c_eeprom_std_write(struct udevice *dev, int 
offset,
int ret;

while (size > 0) {
-   int write_size = min_t(int, size, priv->pagesize);
+   int write_size = i2c_eeprom_len(offset, size, priv->pagesize);

ret = dm_i2c_write(dev, offset, buf, write_size);
if (ret)
--
2.34.1

[PATCH] misc: i2c_eeprom: consider pagesize when writing to eeprom

[Michel Alex]

Calculate the maximum length of the buffer when writing
accross the page boundary. If the buffer length exceeds
the page boundary, split it. Use this length instead of
comparing the length with the pagesize, because the write
start address can be somewhere in the middle of a page.

Signed-off-by: Alex Michel 
---
 drivers/misc/i2c_eeprom.c | 13 -
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/i2c_eeprom.c b/drivers/misc/i2c_eeprom.c
index bdd7e018cc..f345e34179 100644
--- a/drivers/misc/i2c_eeprom.c
+++ b/drivers/misc/i2c_eeprom.c
@@ -60,6 +60,17 @@ static int i2c_eeprom_std_read(struct udevice *dev, int 
offset, u
int8_t *buf,
return dm_i2c_read(dev, offset, buf, size);
 }
 
+static int i2c_eeprom_len(unsigned offset, unsigned len, unsigned pagesize)
+{
+   int page_offset =   ((offset) & (pagesize - 1));
+   unsigned maxlen = pagesize - page_offset;
+
+   if (len > maxlen)
+   len = maxlen;
+
+   return len;
+}
+
 static int i2c_eeprom_std_write(struct udevice *dev, int offset,
const uint8_t *buf, int size)
 {
@@ -67,7 +78,7 @@ static int i2c_eeprom_std_write(struct udevice *dev, int 
offset,
int ret;
 
while (size > 0) {
-   int write_size = min_t(int, size, priv->pagesize);
+   int write_size = i2c_eeprom_len(offset, size, priv->pagesize);
 
ret = dm_i2c_write(dev, offset, buf, write_size);
if (ret)
-- 
2.34.1