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net: sfp: initialize sfp->i2c_block_size at sfp allocation

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commit 813c2dd78618f108fdcf9cd726ea90f081ee2881 upstream.

sfp->i2c_block_size is initialized at SFP module insertion in
sfp_sm_mod_probe(). Because of that, if SFP module was never inserted
since boot, sfp_read() call will lead to zero-length I2C read attempt,
and not all I2C controllers are happy with zero-length reads.

One way to issue sfp_read() on empty SFP cage is to execute ethtool -m.
If SFP module was never plugged since boot, there will be a zero-length
I2C read attempt.

  # ethtool -m xge0
  i2c i2c-3: adapter quirk: no zero length (addr 0x0050, size 0, read)
  Cannot get Module EEPROM data: Operation not supported

If SFP module was plugged then removed at least once,
sfp->i2c_block_size will be initialized and ethtool -m will fail with
different exit code and without I2C error

  # ethtool -m xge0
  Cannot get Module EEPROM data: Remote I/O error

Fix this by initializing sfp->i2_block_size at struct sfp allocation
stage so no wild sfp_read() could issue zero-length I2C read.

Signed-off-by: Ivan Bornyakov <i.bornyakov@metrotek.ru>
Fixes: 0d035bed2a4a ("net: sfp: VSOL V2801F / CarlitoxxPro CPGOS03-0490 v2.0 workaround")
Cc: stable@vger.kernel.org
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ivan Bornyakov
2023-04-06 16:08:32 +03:00
committed by Greg Kroah-Hartman
parent 2a4835b8ed
commit cf22c98bcb
1 changed files with 8 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

13
drivers/net/phy/sfp.c
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@@ -207,6 +207,12 @@ static const enum gpiod_flags gpio_flags[] = {
*/ */
#define SFP_PHY_ADDR 22 #define SFP_PHY_ADDR 22
/* SFP_EEPROM_BLOCK_SIZE is the size of data chunk to read the EEPROM
* at a time. Some SFP modules and also some Linux I2C drivers do not like
* reads longer than 16 bytes.
*/
#define SFP_EEPROM_BLOCK_SIZE 16
struct sff_data { struct sff_data {
unsigned int gpios; unsigned int gpios;
bool (*module_supported)(const struct sfp_eeprom_id *id); bool (*module_supported)(const struct sfp_eeprom_id *id);
@@ -1754,11 +1760,7 @@ static int sfp_sm_mod_probe(struct sfp *sfp, bool report)
u8 check; u8 check;
int ret; int ret;
/* Some SFP modules and also some Linux I2C drivers do not like reads sfp->i2c_block_size = SFP_EEPROM_BLOCK_SIZE;
* longer than 16 bytes, so read the EEPROM in chunks of 16 bytes at
* a time.
*/
sfp->i2c_block_size = 16;
ret = sfp_read(sfp, false, 0, &id.base, sizeof(id.base)); ret = sfp_read(sfp, false, 0, &id.base, sizeof(id.base));
if (ret < 0) { if (ret < 0) {
@@ -2385,6 +2387,7 @@ static struct sfp *sfp_alloc(struct device *dev)
return ERR_PTR(-ENOMEM); return ERR_PTR(-ENOMEM);
sfp->dev = dev; sfp->dev = dev;
sfp->i2c_block_size = SFP_EEPROM_BLOCK_SIZE;
mutex_init(&sfp->sm_mutex); mutex_init(&sfp->sm_mutex);
mutex_init(&sfp->st_mutex); mutex_init(&sfp->st_mutex);