amd-xgbe: Add I2C support for sideband communication

Add support to initialize and use the I2C controller within the hardware
in order to perform sideband communication, e.g. determine the SFP media
type that is installed.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 64 insertions, 0 deletions

diff --git a/drivers/net/ethernet/amd/xgbe/xgbe.h b/drivers/net/ethernet/amd/xgbe/xgbe.h
index 2f0b0b4c611d..586154f4562f 100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe.h
+++ b/drivers/net/ethernet/amd/xgbe/xgbe.h
@@ -127,6 +127,7 @@
 #include <linux/timecounter.h>
 #include <linux/net_tstamp.h>
 #include <net/dcbnl.h>
+#include <linux/completion.h>
 
 #define XGBE_DRV_NAME		"amd-xgbe"
 #define XGBE_DRV_VERSION	"1.0.3"
@@ -555,6 +556,43 @@ struct xgbe_phy {
 	int rx_pause;
 };
 
+enum xgbe_i2c_cmd {
+	XGBE_I2C_CMD_READ = 0,
+	XGBE_I2C_CMD_WRITE,
+};
+
+struct xgbe_i2c_op {
+	enum xgbe_i2c_cmd cmd;
+
+	unsigned int target;
+
+	void *buf;
+	unsigned int len;
+};
+
+struct xgbe_i2c_op_state {
+	struct xgbe_i2c_op *op;
+
+	unsigned int tx_len;
+	unsigned char *tx_buf;
+
+	unsigned int rx_len;
+	unsigned char *rx_buf;
+
+	unsigned int tx_abort_source;
+
+	int ret;
+};
+
+struct xgbe_i2c {
+	unsigned int started;
+	unsigned int max_speed_mode;
+	unsigned int rx_fifo_size;
+	unsigned int tx_fifo_size;
+
+	struct xgbe_i2c_op_state op_state;
+};
+
 struct xgbe_mmc_stats {
 	/* Tx Stats */
 	u64 txoctetcount_gb;
@@ -777,6 +815,21 @@ struct xgbe_phy_if {
 	struct xgbe_phy_impl_if phy_impl;
 };
 
+struct xgbe_i2c_if {
+	/* For initial I2C setup */
+	int (*i2c_init)(struct xgbe_prv_data *);
+
+	/* For I2C support when setting device up/down */
+	int (*i2c_start)(struct xgbe_prv_data *);
+	void (*i2c_stop)(struct xgbe_prv_data *);
+
+	/* For performing I2C operations */
+	int (*i2c_xfer)(struct xgbe_prv_data *, struct xgbe_i2c_op *);
+
+	/* For single interrupt support */
+	irqreturn_t (*i2c_isr)(int, struct xgbe_prv_data *);
+};
+
 struct xgbe_desc_if {
 	int (*alloc_ring_resources)(struct xgbe_prv_data *);
 	void (*free_ring_resources)(struct xgbe_prv_data *);
@@ -842,6 +895,7 @@ struct xgbe_version_data {
 	unsigned int rx_max_fifo_size;
 	unsigned int tx_tstamp_workaround;
 	unsigned int ecc_support;
+	unsigned int i2c_support;
 };
 
 struct xgbe_prv_data {
@@ -915,6 +969,7 @@ struct xgbe_prv_data {
 	struct xgbe_hw_if hw_if;
 	struct xgbe_phy_if phy_if;
 	struct xgbe_desc_if desc_if;
+	struct xgbe_i2c_if i2c_if;
 
 	/* AXI DMA settings */
 	unsigned int coherent;
@@ -1065,6 +1120,12 @@ struct xgbe_prv_data {
 	unsigned long an_start;
 	enum xgbe_an_mode an_mode;
 
+	/* I2C support */
+	struct xgbe_i2c i2c;
+	struct mutex i2c_mutex;
+	struct completion i2c_complete;
+	char i2c_name[IFNAMSIZ + 32];
+
 	unsigned int lpm_ctrl;		/* CTRL1 for resume */
 
 #ifdef CONFIG_DEBUG_FS
@@ -1076,6 +1137,8 @@ struct xgbe_prv_data {
 	unsigned int debugfs_xpcs_reg;
 
 	unsigned int debugfs_xprop_reg;
+
+	unsigned int debugfs_xi2c_reg;
 #endif
 };
 
@@ -1101,6 +1164,7 @@ void xgbe_init_function_ptrs_phy(struct xgbe_phy_if *);
 void xgbe_init_function_ptrs_phy_v1(struct xgbe_phy_if *);
 void xgbe_init_function_ptrs_phy_v2(struct xgbe_phy_if *);
 void xgbe_init_function_ptrs_desc(struct xgbe_desc_if *);
+void xgbe_init_function_ptrs_i2c(struct xgbe_i2c_if *);
 const struct net_device_ops *xgbe_get_netdev_ops(void);
 const struct ethtool_ops *xgbe_get_ethtool_ops(void);