net/mlx4_core: Introduce mlx4_get_module_info for cable module info reading

Added new MAD_IFC command to read cable module info with attribute id (0xFF60).
Update include/linux/mlx4/device.h with function declaration (mlx4_get_module_info)
and the needed defines/enums for future use.

Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 186 insertions, 0 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx4/port.c b/drivers/net/ethernet/mellanox/mlx4/port.c
index 94eeb2c7d7e4..30eb1ead0fe6 100644
--- a/drivers/net/ethernet/mellanox/mlx4/port.c
+++ b/drivers/net/ethernet/mellanox/mlx4/port.c
@@ -1311,3 +1311,159 @@ int mlx4_get_roce_gid_from_slave(struct mlx4_dev *dev, int port, int slave_id,
         return 0;
 }
 EXPORT_SYMBOL(mlx4_get_roce_gid_from_slave);
+
+/* Cable Module Info */
+#define MODULE_INFO_MAX_READ 48
+
+#define I2C_ADDR_LOW  0x50
+#define I2C_ADDR_HIGH 0x51
+#define I2C_PAGE_SIZE 256
+
+/* Module Info Data */
+struct mlx4_cable_info {
+        u8      i2c_addr;
+        u8      page_num;
+        __be16  dev_mem_address;
+        __be16  reserved1;
+        __be16  size;
+        __be32  reserved2[2];
+        u8      data[MODULE_INFO_MAX_READ];
+};
+
+enum cable_info_err {
+         CABLE_INF_INV_PORT      = 0x1,
+         CABLE_INF_OP_NOSUP      = 0x2,
+         CABLE_INF_NOT_CONN      = 0x3,
+         CABLE_INF_NO_EEPRM      = 0x4,
+         CABLE_INF_PAGE_ERR      = 0x5,
+         CABLE_INF_INV_ADDR      = 0x6,
+         CABLE_INF_I2C_ADDR      = 0x7,
+         CABLE_INF_QSFP_VIO      = 0x8,
+         CABLE_INF_I2C_BUSY      = 0x9,
+};
+
+#define MAD_STATUS_2_CABLE_ERR(mad_status) ((mad_status >> 8) & 0xFF)
+
+static inline const char *cable_info_mad_err_str(u16 mad_status)
+{
+        u8 err = MAD_STATUS_2_CABLE_ERR(mad_status);
+
+        switch (err) {
+        case CABLE_INF_INV_PORT:
+                return "invalid port selected";
+        case CABLE_INF_OP_NOSUP:
+                return "operation not supported for this port (the port is of type CX4 or internal)";
+        case CABLE_INF_NOT_CONN:
+                return "cable is not connected";
+        case CABLE_INF_NO_EEPRM:
+                return "the connected cable has no EPROM (passive copper cable)";
+        case CABLE_INF_PAGE_ERR:
+                return "page number is greater than 15";
+        case CABLE_INF_INV_ADDR:
+                return "invalid device_address or size (that is, size equals 0 or address+size is greater than 256)";
+        case CABLE_INF_I2C_ADDR:
+                return "invalid I2C slave address";
+        case CABLE_INF_QSFP_VIO:
+                return "at least one cable violates the QSFP specification and ignores the modsel signal";
+        case CABLE_INF_I2C_BUSY:
+                return "I2C bus is constantly busy";
+        }
+        return "Unknown Error";
+}
+
+/**
+ * mlx4_get_module_info - Read cable module eeprom data
+ * @dev: mlx4_dev.
+ * @port: port number.
+ * @offset: byte offset in eeprom to start reading data from.
+ * @size: num of bytes to read.
+ * @data: output buffer to put the requested data into.
+ *
+ * Reads cable module eeprom data, puts the outcome data into
+ * data pointer paramer.
+ * Returns num of read bytes on success or a negative error
+ * code.
+ */
+int mlx4_get_module_info(struct mlx4_dev *dev, u8 port,
+                         u16 offset, u16 size, u8 *data)
+{
+        struct mlx4_cmd_mailbox *inbox, *outbox;
+        struct mlx4_mad_ifc *inmad, *outmad;
+        struct mlx4_cable_info *cable_info;
+        u16 i2c_addr;
+        int ret;
+
+        if (size > MODULE_INFO_MAX_READ)
+                size = MODULE_INFO_MAX_READ;
+
+        inbox = mlx4_alloc_cmd_mailbox(dev);
+        if (IS_ERR(inbox))
+                return PTR_ERR(inbox);
+
+        outbox = mlx4_alloc_cmd_mailbox(dev);
+        if (IS_ERR(outbox)) {
+                mlx4_free_cmd_mailbox(dev, inbox);
+                return PTR_ERR(outbox);
+        }
+
+        inmad = (struct mlx4_mad_ifc *)(inbox->buf);
+        outmad = (struct mlx4_mad_ifc *)(outbox->buf);
+
+        inmad->method = 0x1; /* Get */
+        inmad->class_version = 0x1;
+        inmad->mgmt_class = 0x1;
+        inmad->base_version = 0x1;
+        inmad->attr_id = cpu_to_be16(0xFF60); /* Module Info */
+
+        if (offset < I2C_PAGE_SIZE && offset + size > I2C_PAGE_SIZE)
+                /* Cross pages reads are not allowed
+                 * read until offset 256 in low page
+                 */
+                size -= offset + size - I2C_PAGE_SIZE;
+
+        i2c_addr = I2C_ADDR_LOW;
+        if (offset >= I2C_PAGE_SIZE) {
+                /* Reset offset to high page */
+                i2c_addr = I2C_ADDR_HIGH;
+                offset -= I2C_PAGE_SIZE;
+        }
+
+        cable_info = (struct mlx4_cable_info *)inmad->data;
+        cable_info->dev_mem_address = cpu_to_be16(offset);
+        cable_info->page_num = 0;
+        cable_info->i2c_addr = i2c_addr;
+        cable_info->size = cpu_to_be16(size);
+
+        ret = mlx4_cmd_box(dev, inbox->dma, outbox->dma, port, 3,
+                           MLX4_CMD_MAD_IFC, MLX4_CMD_TIME_CLASS_C,
+                           MLX4_CMD_NATIVE);
+        if (ret)
+                goto out;
+
+        if (be16_to_cpu(outmad->status)) {
+                /* Mad returned with bad status */
+                ret = be16_to_cpu(outmad->status);
+                mlx4_warn(dev,
+                          "MLX4_CMD_MAD_IFC Get Module info attr(%x) port(%d) i2c_addr(%x) offset(%d) size(%d): Response Mad Status(%x) - %s\n",
+                          0xFF60, port, i2c_addr, offset, size,
+                          ret, cable_info_mad_err_str(ret));
+
+                if (i2c_addr == I2C_ADDR_HIGH &&
+                    MAD_STATUS_2_CABLE_ERR(ret) == CABLE_INF_I2C_ADDR)
+                        /* Some SFP cables do not support i2c slave
+                         * address 0x51 (high page), abort silently.
+                         */
+                        ret = 0;
+                else
+                        ret = -ret;
+                goto out;
+        }
+        cable_info = (struct mlx4_cable_info *)outmad->data;
+        memcpy(data, cable_info->data, size);
+        ret = size;
+out:
+        mlx4_free_cmd_mailbox(dev, inbox);
+        mlx4_free_cmd_mailbox(dev, outbox);
+        return ret;
+}
+EXPORT_SYMBOL(mlx4_get_module_info);
diff --git a/include/linux/mlx4/device.h b/include/linux/mlx4/device.h
index 37e4404d0227..73910daec317 100644
--- a/include/linux/mlx4/device.h
+++ b/include/linux/mlx4/device.h
@@ -379,6 +379,13 @@ enum {
 #define MSTR_SM_CHANGE_MASK (MLX4_EQ_PORT_INFO_MSTR_SM_SL_CHANGE_MASK | \
                              MLX4_EQ_PORT_INFO_MSTR_SM_LID_CHANGE_MASK)
 
+enum mlx4_module_id {
+        MLX4_MODULE_ID_SFP              = 0x3,
+        MLX4_MODULE_ID_QSFP             = 0xC,
+        MLX4_MODULE_ID_QSFP_PLUS        = 0xD,
+        MLX4_MODULE_ID_QSFP28           = 0x11,
+};
+
 static inline u64 mlx4_fw_ver(u64 major, u64 minor, u64 subminor)
 {
         return (major << 32) | (minor << 16) | subminor;
@@ -799,6 +806,26 @@ struct mlx4_init_port_param {
         u64                     si_guid;
 };
 
+#define MAD_IFC_DATA_SZ 192
+/* MAD IFC Mailbox */
+struct mlx4_mad_ifc {
+        u8      base_version;
+        u8      mgmt_class;
+        u8      class_version;
+        u8      method;
+        __be16  status;
+        __be16  class_specific;
+        __be64  tid;
+        __be16  attr_id;
+        __be16  resv;
+        __be32  attr_mod;
+        __be64  mkey;
+        __be16  dr_slid;
+        __be16  dr_dlid;
+        u8      reserved[28];
+        u8      data[MAD_IFC_DATA_SZ];
+} __packed;
+
 #define mlx4_foreach_port(port, dev, type)                              \
         for ((port) = 1; (port) <= (dev)->caps.num_ports; (port)++)     \
                 if ((type) == (dev)->caps.port_mask[(port)])
@@ -1283,6 +1310,9 @@ int mlx4_mr_rereg_mem_write(struct mlx4_dev *dev, struct mlx4_mr *mr,
                             u64 iova, u64 size, int npages,
                             int page_shift, struct mlx4_mpt_entry *mpt_entry);
 
+int mlx4_get_module_info(struct mlx4_dev *dev, u8 port,
+                         u16 offset, u16 size, u8 *data);
+
 /* Returns true if running in low memory profile (kdump kernel) */
 static inline bool mlx4_low_memory_profile(void)
 {