nfp: nsp: implement read SFF module EEPROM

The NSP now provides the ability to read from the SFF module EEPROM.
Note that even if an error occurs, the NSP may still provide some of the
data.
Signed-off-by: NDirk van der Merwe <dirk.vandermerwe@netronome.com>
Reviewed-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/netronome/nfp/nfpcore/nfp_nsp.c

@@ -79,6 +79,8 @@
 #define NFP_VERSIONS_NCSI_OFF	22
 #define NFP_VERSIONS_CFGR_OFF	26
 
+#define NSP_SFF_EEPROM_BLOCK_LEN	8
+
 enum nfp_nsp_cmd {
 	SPCODE_NOOP		= 0, /* No operation */
 	SPCODE_SOFT_RESET	= 1, /* Soft reset the NFP */
@@ -95,6 +97,7 @@ enum nfp_nsp_cmd {
 	SPCODE_FW_STORED	= 16, /* If no FW loaded, load flash app FW */
 	SPCODE_HWINFO_LOOKUP	= 17, /* Lookup HWinfo with overwrites etc. */
 	SPCODE_VERSIONS		= 21, /* Report FW versions */
+	SPCODE_READ_SFF_EEPROM	= 22, /* Read module EEPROM */
 };
 
 struct nfp_nsp_dma_buf {
@@ -965,3 +968,62 @@ const char *nfp_nsp_versions_get(enum nfp_nsp_versions id, bool flash,
 
 	return (const char *)&buf[buf_off];
 }
+
+static int
+__nfp_nsp_module_eeprom(struct nfp_nsp *state, void *buf, unsigned int size)
+{
+	struct nfp_nsp_command_buf_arg module_eeprom = {
+		{
+			.code		= SPCODE_READ_SFF_EEPROM,
+			.option		= size,
+		},
+		.in_buf		= buf,
+		.in_size	= size,
+		.out_buf	= buf,
+		.out_size	= size,
+	};
+
+	return nfp_nsp_command_buf(state, &module_eeprom);
+}
+
+int nfp_nsp_read_module_eeprom(struct nfp_nsp *state, int eth_index,
+			       unsigned int offset, void *data,
+			       unsigned int len, unsigned int *read_len)
+{
+	struct eeprom_buf {
+		u8 metalen;
+		__le16 length;
+		__le16 offset;
+		__le16 readlen;
+		u8 eth_index;
+		u8 data[0];
+	} __packed *buf;
+	int bufsz, ret;
+
+	BUILD_BUG_ON(offsetof(struct eeprom_buf, data) % 8);
+
+	/* Buffer must be large enough and rounded to the next block size. */
+	bufsz = struct_size(buf, data, round_up(len, NSP_SFF_EEPROM_BLOCK_LEN));
+	buf = kzalloc(bufsz, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	buf->metalen =
+		offsetof(struct eeprom_buf, data) / NSP_SFF_EEPROM_BLOCK_LEN;
+	buf->length = cpu_to_le16(len);
+	buf->offset = cpu_to_le16(offset);
+	buf->eth_index = eth_index;
+
+	ret = __nfp_nsp_module_eeprom(state, buf, bufsz);
+
+	*read_len = min_t(unsigned int, len, le16_to_cpu(buf->readlen));
+	if (*read_len)
+		memcpy(data, buf->data, *read_len);
+
+	if (!ret && *read_len < len)
+		ret = -EIO;
+
+	kfree(buf);
+
+	return ret;
+}

drivers/net/ethernet/netronome/nfp/nfpcore/nfp_nsp.h

@@ -22,6 +22,9 @@ int nfp_nsp_write_flash(struct nfp_nsp *state, const struct firmware *fw);
 int nfp_nsp_mac_reinit(struct nfp_nsp *state);
 int nfp_nsp_load_stored_fw(struct nfp_nsp *state);
 int nfp_nsp_hwinfo_lookup(struct nfp_nsp *state, void *buf, unsigned int size);
+int nfp_nsp_read_module_eeprom(struct nfp_nsp *state, int eth_index,
+			       unsigned int offset, void *data,
+			       unsigned int len, unsigned int *read_len);
 
 static inline bool nfp_nsp_has_mac_reinit(struct nfp_nsp *state)
 {
@@ -43,6 +46,11 @@ static inline bool nfp_nsp_has_versions(struct nfp_nsp *state)
 	return nfp_nsp_get_abi_ver_minor(state) > 27;
 }
 
+static inline bool nfp_nsp_has_read_module_eeprom(struct nfp_nsp *state)
+{
+	return nfp_nsp_get_abi_ver_minor(state) > 28;
+}
+
 enum nfp_eth_interface {
 	NFP_INTERFACE_NONE	= 0,
 	NFP_INTERFACE_SFP	= 1,