brcm47xx: support SPROM/NVRAM prefixes

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>

SVN-Revision: 44855

target/linux/brcm47xx/patches-3.18/100-MIPS-BCM47XX-Support-SPROM-prefixes-for-PCI-devices.patch

@@ -0,0 +1,74 @@
+From f3505e9283290dd9bb6197bd485e6cbfb5beaf7e Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <zajec5@gmail.com>
+Date: Wed, 11 Mar 2015 19:24:42 +0100
+Subject: [PATCH V2] MIPS: BCM47XX: Support SPROM prefixes for PCI devices
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Support parsing SPROMs with prefixes defined like devpath1=pci/1/1
+
+Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
+---
+V2: I've noticed that Buffalo WZR-1750 uses an extra slash in NVRAM
+    devpaths entries. I added support for them and updated comment.
+    This adds one line over 80 chars, but it improved condition
+    readability so I think it's alright there. 
+---
+ arch/mips/bcm47xx/sprom.c | 33 +++++++++++++++++++++++++++++++++
+ 1 file changed, 33 insertions(+)
+
+diff --git a/arch/mips/bcm47xx/sprom.c b/arch/mips/bcm47xx/sprom.c
+index 290309e..5d32afc 100644
+--- a/arch/mips/bcm47xx/sprom.c
++++ b/arch/mips/bcm47xx/sprom.c
+@@ -822,6 +822,38 @@ static int bcm47xx_get_sprom_ssb(struct ssb_bus *bus, struct ssb_sprom *out)
+ #endif
+ 
+ #if defined(CONFIG_BCM47XX_BCMA)
++/*
++ * Having many NVRAM entries for PCI devices led to repeating prefixes like
++ * pci/1/1/ all the time and wasting flash space. So at some point Broadcom
++ * decided to introduce prefixes like 0: 1: 2: etc.
++ * If we find e.g. devpath0=pci/2/1 or devpath0=pci/2/1/ we should use 0:
++ * instead of pci/2/1/.
++ */
++static void bcm47xx_sprom_apply_prefix_alias(char *prefix, size_t prefix_size)
++{
++	size_t prefix_len = strlen(prefix);
++	size_t short_len = prefix_len - 1;
++	char nvram_var[10];
++	char buf[20];
++	int i;
++
++	/* Passed prefix has to end with a slash */
++	if (prefix_len <= 0 || prefix[prefix_len - 1] != '/')
++		return;
++
++	for (i = 0; i < 3; i++) {
++		if (snprintf(nvram_var, sizeof(nvram_var), "devpath%d", i) <= 0)
++			continue;
++		if (bcm47xx_nvram_getenv(nvram_var, buf, sizeof(buf)) < 0)
++			continue;
++		if (!strcmp(buf, prefix) ||
++		    (short_len && strlen(buf) == short_len && !strncmp(buf, prefix, short_len))) {
++			snprintf(prefix, prefix_size, "%d:", i);
++			return;
++		}
++	}
++}
++
+ static int bcm47xx_get_sprom_bcma(struct bcma_bus *bus, struct ssb_sprom *out)
+ {
+ 	char prefix[10];
+@@ -833,6 +865,7 @@ static int bcm47xx_get_sprom_bcma(struct bcma_bus *bus, struct ssb_sprom *out)
+ 		snprintf(prefix, sizeof(prefix), "pci/%u/%u/",
+ 			 bus->host_pci->bus->number + 1,
+ 			 PCI_SLOT(bus->host_pci->devfn));
++		bcm47xx_sprom_apply_prefix_alias(prefix, sizeof(prefix));
+ 		bcm47xx_fill_sprom(out, prefix, false);
+ 		return 0;
+ 	case BCMA_HOSTTYPE_SOC:
+-- 
+1.8.4.5
+