Increase optoe's write-max to support i2c block write (sonic-net#230)

Dynamic write_max support for optoe driver


Signed-off-by: Prince George <[email protected]>

patch/driver-support-optoe-write-max.patch

@@ -0,0 +1,86 @@
+From ca9daf437f0910493a6eb8ced900662223ea3cf7 Mon Sep 17 00:00:00 2001
+From: Prince George <[email protected]>
+Date: Mon, 16 Aug 2021 16:04:15 +0000
+Subject: [PATCH] Dynamic write_max support for optoe driver  
+ In current optoe driver, the value of write_max is  hardcoded to one byte.  
+ CMIS spec supports firmware upgrade on QSFP-DD transceivers which means  
+ there is significant overhead due to this one byte write limit when a
+ platform wants to upgrade the firmware over an i2c bus at 100Khz. 
+ The  overhead is more pronounced when a platform has shared master and 
+ platform needs to perform firmware upgrade  on multiple transceivers.
+
+ Added sysfs file 'write_max' for each i2c device (that use optoe driver)
+ so that the platform can override the default write max which is one byte.
+
+ Test result:-
+ Firmware file of size 1.9MB takes ~ 33 mins with write-max size = 1 Byte
+ Firmware file of size 1.9MB takes ~ 8 mins with write-max size = 64 Bytes
+
+Signed-off-by: Prince George <[email protected]>
+---
+ drivers/misc/eeprom/optoe.c | 36 ++++++++++++++++++++++++++++++++++++
+ 1 file changed, 36 insertions(+)
+
+diff --git a/drivers/misc/eeprom/optoe.c b/drivers/misc/eeprom/optoe.c
+index 16287fdc5..cacfb1848 100644
+--- a/drivers/misc/eeprom/optoe.c
++++ b/drivers/misc/eeprom/optoe.c
+@@ -822,6 +822,39 @@ static int optoe_remove(struct i2c_client *client)
+ 	return 0;
+ }
+
++static ssize_t show_dev_write_max_size(struct device *dev,
++			struct device_attribute *dattr, char *buf)
++{
++	struct i2c_client *client = to_i2c_client(dev);
++	struct optoe_data *optoe = i2c_get_clientdata(client);
++	ssize_t count;
++
++	mutex_lock(&optoe->lock);
++	count = sprintf(buf, "%u\n", optoe->write_max);
++	mutex_unlock(&optoe->lock);
++
++	return count;
++}
++
++static ssize_t set_dev_write_max_size(struct device *dev,
++			struct device_attribute *attr,
++			const char *buf, size_t count)
++{
++	struct i2c_client *client = to_i2c_client(dev);
++	struct optoe_data *optoe = i2c_get_clientdata(client);
++	int write_max_size;
++
++	if (kstrtouint(buf, 0, &write_max_size) != 0 ||
++		write_max_size < 1 || write_max_size > OPTOE_PAGE_SIZE)
++		return -EINVAL;
++
++	mutex_lock(&optoe->lock);
++	optoe->write_max = write_max_size;
++	mutex_unlock(&optoe->lock);
++
++	return count;
++}
++
+ static ssize_t show_dev_class(struct device *dev,
+ 			struct device_attribute *dattr, char *buf)
+ {
+@@ -928,12 +961,15 @@ static ssize_t set_port_name(struct device *dev,
+ static DEVICE_ATTR(port_name,  0644, show_port_name, set_port_name);
+ #endif  /* if NOT defined EEPROM_CLASS, the common case */
+
++static DEVICE_ATTR(write_max, 0644, show_dev_write_max_size,
++					set_dev_write_max_size);
+ static DEVICE_ATTR(dev_class,  0644, show_dev_class, set_dev_class);
+
+ static struct attribute *optoe_attrs[] = {
+ #ifndef EEPROM_CLASS
+ 	&dev_attr_port_name.attr,
+ #endif
++	&dev_attr_write_max.attr,
+ 	&dev_attr_dev_class.attr,
+ 	NULL,
+ };
+-- 
+2.17.1
+

patch/series

@@ -30,6 +30,7 @@ driver-support-optoe.patch
 driver-support-optoe-EOF_fix.patch
 driver-support-optoe-chunk-offset-fix.patch
 driver-support-optoe-QSFP_DD.patch
+driver-support-optoe-write-max.patch
 driver-net-tg3-add-param-short-preamble-and-reset.patch
 0001-hwmon-lm75-add-support-for-PCT2075.patch
 0004-dt-bindings-hwmon-Add-missing-documentation-for-lm75.patch