myri10ge: remove hardcoded sram_size

Removes the use of a hardcoded sram_size, determine string_spec
location from the MCP header instead.
Signed-off-by: Brice Goglin <brice@myri.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/myri10ge/myri10ge.c

@@ -3739,6 +3739,7 @@ static int myri10ge_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	int i;
 	int status = -ENXIO;
 	int dac_enabled;
+	unsigned hdr_offset, ss_offset;
 
 	netdev = alloc_etherdev_mq(sizeof(*mgp), MYRI10GE_MAX_SLICES);
 	if (netdev == NULL) {
@@ -3806,14 +3807,6 @@ static int myri10ge_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	if (mgp->mtrr >= 0)
 		mgp->wc_enabled = 1;
 #endif
-	/* Hack.  need to get rid of these magic numbers */
-	mgp->sram_size =
-	    2 * 1024 * 1024 - (2 * (48 * 1024) + (32 * 1024)) - 0x100;
-	if (mgp->sram_size > mgp->board_span) {
-		dev_err(&pdev->dev, "board span %ld bytes too small\n",
-			mgp->board_span);
-		goto abort_with_mtrr;
-	}
 	mgp->sram = ioremap_wc(mgp->iomem_base, mgp->board_span);
 	if (mgp->sram == NULL) {
 		dev_err(&pdev->dev, "ioremap failed for %ld bytes at 0x%lx\n",
@@ -3821,9 +3814,19 @@ static int myri10ge_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 		status = -ENXIO;
 		goto abort_with_mtrr;
 	}
+	hdr_offset =
+	    ntohl(__raw_readl(mgp->sram + MCP_HEADER_PTR_OFFSET)) & 0xffffc;
+	ss_offset = hdr_offset + offsetof(struct mcp_gen_header, string_specs);
+	mgp->sram_size = ntohl(__raw_readl(mgp->sram + ss_offset));
+	if (mgp->sram_size > mgp->board_span ||
+	    mgp->sram_size <= MYRI10GE_FW_OFFSET) {
+		dev_err(&pdev->dev,
+			"invalid sram_size %dB or board span %ldB\n",
+			mgp->sram_size, mgp->board_span);
+		goto abort_with_ioremap;
+	}
 	memcpy_fromio(mgp->eeprom_strings,
-		      mgp->sram + mgp->sram_size - MYRI10GE_EEPROM_STRINGS_SIZE,
-		      MYRI10GE_EEPROM_STRINGS_SIZE);
+		      mgp->sram + mgp->sram_size, MYRI10GE_EEPROM_STRINGS_SIZE);
 	memset(mgp->eeprom_strings + MYRI10GE_EEPROM_STRINGS_SIZE - 2, 0, 2);
 	status = myri10ge_read_mac_addr(mgp);
 	if (status)