From 332b8f6ca7da3197c631928b6bd1e7fdca87e109 Mon Sep 17 00:00:00 2001
From: Hauke Mehrtens <hauke@hauke-m.de>
Date: Sat, 18 Feb 2012 01:16:35 +0100
Subject: [PATCH 195/202] bcma: add support for sprom not found on the device.

On SoCs the sprom is stored in the nvram in a special partition on the
flash chip. The nvram contains the sprom for the main bus, but
sometimes also for a pci devices using bcma. This patch makes it
possible for the arch code to register a function to fetch the needed
sprom from the nvram and provide it to the bcma code.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
---
 drivers/bcma/sprom.c      |   80 ++++++++++++++++++++++++++++++++++++++++----
 include/linux/bcma/bcma.h |    6 +++
 2 files changed, 78 insertions(+), 8 deletions(-)

--- a/drivers/bcma/sprom.c
+++ b/drivers/bcma/sprom.c
@@ -16,6 +16,49 @@
 
 #define SPOFF(offset)	((offset) / sizeof(u16))
 
+static int(*get_fallback_sprom)(struct bcma_bus *dev, struct ssb_sprom *out);
+
+/**
+ * ssb_arch_register_fallback_sprom - Registers a method providing a
+ * fallback SPROM if no SPROM is found.
+ *
+ * @sprom_callback: The callback function.
+ *
+ * With this function the architecture implementation may register a
+ * callback handler which fills the SPROM data structure. The fallback is
+ * only used for PCI based SSB devices, where no valid SPROM can be found
+ * in the shadow registers.
+ *
+ * This function is useful for weird architectures that have a half-assed
+ * SSB device hardwired to their PCI bus.
+ *
+ * Note that it does only work with PCI attached SSB devices. PCMCIA
+ * devices currently don't use this fallback.
+ * Architectures must provide the SPROM for native SSB devices anyway, so
+ * the fallback also isn't used for native devices.
+ *
+ * This function is available for architecture code, only. So it is not
+ * exported.
+ */
+int bcma_arch_register_fallback_sprom(int (*sprom_callback)(struct bcma_bus *bus,
+				     struct ssb_sprom *out))
+{
+	if (get_fallback_sprom)
+		return -EEXIST;
+	get_fallback_sprom = sprom_callback;
+
+	return 0;
+}
+
+static int bcma_fill_sprom_with_fallback(struct bcma_bus *bus,
+					 struct ssb_sprom *out)
+{
+	if (!get_fallback_sprom)
+		return -ENOENT;
+
+	return get_fallback_sprom(bus, out);
+}
+
 /**************************************************
  * R/W ops.
  **************************************************/
@@ -205,23 +248,44 @@ static void bcma_sprom_extract_r8(struct
 		SSB_SROM8_FEM_ANTSWLUT) >> SSB_SROM8_FEM_ANTSWLUT_SHIFT;
 }
 
+static bool bcma_is_sprom_available(struct bcma_bus *bus)
+{
+	u32 sromctrl;
+
+	if (!(bus->drv_cc.capabilities & BCMA_CC_CAP_SPROM))
+		return false;
+
+	if (bus->drv_cc.core->id.rev >= 32) {
+		sromctrl = bcma_read32(bus->drv_cc.core, BCMA_CC_SROM_CONTROL);
+		if (!(sromctrl & BCMA_CC_SROM_CONTROL_PRESENT))
+			return false;
+	}
+	return true;
+}
+
 int bcma_sprom_get(struct bcma_bus *bus)
 {
 	u16 offset;
 	u16 *sprom;
-	u32 sromctrl;
 	int err = 0;
 
 	if (!bus->drv_cc.core)
 		return -EOPNOTSUPP;
 
-	if (!(bus->drv_cc.capabilities & BCMA_CC_CAP_SPROM))
-		return -ENOENT;
-
-	if (bus->drv_cc.core->id.rev >= 32) {
-		sromctrl = bcma_read32(bus->drv_cc.core, BCMA_CC_SROM_CONTROL);
-		if (!(sromctrl & BCMA_CC_SROM_CONTROL_PRESENT))
-			return -ENOENT;
+	if (!bcma_is_sprom_available(bus)) {
+		/*
+		 * Maybe there is no SPROM on the device?
+		 * Now we ask the arch code if there is some sprom
+		 * available for this device in some other storage
+		 */
+		err = bcma_fill_sprom_with_fallback(bus, &bus->sprom);
+		if (err) {
+			pr_warn("Using fallback SPROM failed (err %d)\n", err);
+		} else {
+			pr_debug("Using SPROM revision %d provided by"
+				 " platform.\n", bus->sprom.revision);
+			return 0;
+		}
 	}
 
 	sprom = kcalloc(SSB_SPROMSIZE_WORDS_R4, sizeof(u16),
--- a/include/linux/bcma/bcma.h
+++ b/include/linux/bcma/bcma.h
@@ -177,6 +177,12 @@ int __bcma_driver_register(struct bcma_d
 
 extern void bcma_driver_unregister(struct bcma_driver *drv);
 
+/* Set a fallback SPROM.
+ * See kdoc at the function definition for complete documentation. */
+extern int bcma_arch_register_fallback_sprom(
+		int (*sprom_callback)(struct bcma_bus *bus,
+		struct ssb_sprom *out));
+
 struct bcma_bus {
 	/* The MMIO area. */
 	void __iomem *mmio;