Merge branch 'ethtool-eeprom'

Moshe Shemesh says:

====================
ethtool: Extend module EEPROM dump API

Ethtool supports module EEPROM dumps via the `ethtool -m <dev>` command.
But in current state its functionality is limited - offset and length
parameters, which are used to specify a linear desired region of EEPROM
data to dump, is not enough, considering emergence of complex module
EEPROM layouts such as CMIS 4.0.
Moreover, CMIS 4.0 extends the amount of pages that may be accessible by
introducing another parameter for page addressing - banks.

Besides, currently module EEPROM is represented as a chunk of
concatenated pages, where lower 128 bytes of all pages, except page 00h,
are omitted. Offset and length are used to address parts of this fake
linear memory. But in practice drivers, which implement
get_module_info() and get_module_eeprom() ethtool ops still calculate
page number and set I2C address on their own.

This series tackles these issues by adding ethtool op, which allows to
pass page number, bank number and I2C address in addition to offset and
length parameters to the driver, adds corresponding netlink
infrastructure and implements the new interface in mlx5 driver.

This allows to extend userspace 'ethtool -m' CLI by adding new
parameters - page, bank and i2c. New command line format:
 ethtool -m <dev> [hex on|off] [raw on|off] [offset N] [length N] [page N] [bank N] [i2c N]

The consequence of this series is a possibility to dump arbitrary EEPROM
page at a time, in contrast to dumps of concatenated pages. Therefore,
offset and length change their semantics and may be used only to specify
a part of data within half page boundary, which size is currently limited
to 128 bytes.

As for drivers that support legacy get_module_info() and
get_module_eeprom() pair, the series addresses it by implementing a
fallback mechanism. As mentioned earlier, such drivers derive a page
number from 'global' offset, so this can be done vice versa without
their involvement thanks to standardization. If kernel netlink handler
of 'ethtool -m' command detects that new ethtool op is not supported by
the driver, it calculates offset from given page number and page offset
and calls old ndos, if they are available.
====================

\Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 32 insertions, 1 deletions

diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index 4290e2fa3117..9f6f323af59a 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -81,6 +81,7 @@ enum {
 #define ETH_RSS_HASH_NO_CHANGE	0
 
 struct net_device;
+struct netlink_ext_ack;
 
 /* Some generic methods drivers may use in their ethtool_ops */
 u32 ethtool_op_get_link(struct net_device *dev);
@@ -262,6 +263,31 @@ struct ethtool_pause_stats {
 	u64 rx_pause_frames;
 };
 
+#define ETH_MODULE_EEPROM_PAGE_LEN	128
+#define ETH_MODULE_MAX_I2C_ADDRESS	0x7f
+
+/**
+ * struct ethtool_module_eeprom - EEPROM dump from specified page
+ * @offset: Offset within the specified EEPROM page to begin read, in bytes.
+ * @length: Number of bytes to read.
+ * @page: Page number to read from.
+ * @bank: Page bank number to read from, if applicable by EEPROM spec.
+ * @i2c_address: I2C address of a page. Value less than 0x7f expected. Most
+ *	EEPROMs use 0x50 or 0x51.
+ * @data: Pointer to buffer with EEPROM data of @length size.
+ *
+ * This can be used to manage pages during EEPROM dump in ethtool and pass
+ * required information to the driver.
+ */
+struct ethtool_module_eeprom {
+	__u32	offset;
+	__u32	length;
+	__u8	page;
+	__u8	bank;
+	__u8	i2c_address;
+	__u8	*data;
+};
+
 /**
  * struct ethtool_ops - optional netdev operations
  * @cap_link_lanes_supported: indicates if the driver supports lanes
@@ -414,6 +440,9 @@ struct ethtool_pause_stats {
  *	cannot use the standard PHY library helpers.
  * @get_phy_tunable: Read the value of a PHY tunable.
  * @set_phy_tunable: Set the value of a PHY tunable.
+ * @get_module_eeprom_by_page: Get a region of plug-in module EEPROM data from
+ *	specified page. Returns a negative error code or the amount of bytes
+ *	read.
  *
  * All operations are optional (i.e. the function pointer may be set
  * to %NULL) and callers must take this into account.  Callers must
@@ -519,6 +548,9 @@ struct ethtool_ops {
 				   const struct ethtool_tunable *, void *);
 	int	(*set_phy_tunable)(struct net_device *,
 				   const struct ethtool_tunable *, const void *);
+	int	(*get_module_eeprom_by_page)(struct net_device *dev,
+					     const struct ethtool_module_eeprom *page,
+					     struct netlink_ext_ack *extack);
 };
 
 int ethtool_check_ops(const struct ethtool_ops *ops);
@@ -542,7 +574,6 @@ int ethtool_virtdev_set_link_ksettings(struct net_device *dev,
 				       const struct ethtool_link_ksettings *cmd,
 				       u32 *dev_speed, u8 *dev_duplex);
 
-struct netlink_ext_ack;
 struct phy_device;
 struct phy_tdr_config;