ethtool: Allow network drivers to dump arbitrary EEPROM data

Define get_module_eeprom_by_page() ethtool callback and implement
netlink infrastructure.

get_module_eeprom_by_page() allows network drivers to dump a part of
module's EEPROM specified by page and bank numbers along with offset and
length. It is effectively a netlink replacement for get_module_info()
and get_module_eeprom() pair, which is needed due to emergence of
complex non-linear EEPROM layouts.

Signed-off-by: Vladyslav Tarasiuk <vladyslavt@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 51 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;
 
diff --git a/include/uapi/linux/ethtool_netlink.h b/include/uapi/linux/ethtool_netlink.h
index 7f1bdb5b31ba..9612dcd48a6a 100644
--- a/include/uapi/linux/ethtool_netlink.h
+++ b/include/uapi/linux/ethtool_netlink.h
@@ -44,6 +44,7 @@ enum {
 	ETHTOOL_MSG_TUNNEL_INFO_GET,
 	ETHTOOL_MSG_FEC_GET,
 	ETHTOOL_MSG_FEC_SET,
+	ETHTOOL_MSG_MODULE_EEPROM_GET,
 
 	/* add new constants above here */
 	__ETHTOOL_MSG_USER_CNT,
@@ -84,6 +85,7 @@ enum {
 	ETHTOOL_MSG_TUNNEL_INFO_GET_REPLY,
 	ETHTOOL_MSG_FEC_GET_REPLY,
 	ETHTOOL_MSG_FEC_NTF,
+	ETHTOOL_MSG_MODULE_EEPROM_GET_REPLY,
 
 	/* add new constants above here */
 	__ETHTOOL_MSG_KERNEL_CNT,
@@ -646,6 +648,23 @@ enum {
 	ETHTOOL_A_FEC_MAX = (__ETHTOOL_A_FEC_CNT - 1)
 };
 
+/* MODULE EEPROM */
+
+enum {
+	ETHTOOL_A_MODULE_EEPROM_UNSPEC,
+	ETHTOOL_A_MODULE_EEPROM_HEADER,			/* nest - _A_HEADER_* */
+
+	ETHTOOL_A_MODULE_EEPROM_OFFSET,			/* u32 */
+	ETHTOOL_A_MODULE_EEPROM_LENGTH,			/* u32 */
+	ETHTOOL_A_MODULE_EEPROM_PAGE,			/* u8 */
+	ETHTOOL_A_MODULE_EEPROM_BANK,			/* u8 */
+	ETHTOOL_A_MODULE_EEPROM_I2C_ADDRESS,		/* u8 */
+	ETHTOOL_A_MODULE_EEPROM_DATA,			/* nested */
+
+	__ETHTOOL_A_MODULE_EEPROM_CNT,
+	ETHTOOL_A_MODULE_EEPROM_MAX = (__ETHTOOL_A_MODULE_EEPROM_CNT - 1)
+};
+
 /* generic netlink info */
 #define ETHTOOL_GENL_NAME "ethtool"
 #define ETHTOOL_GENL_VERSION 1