[POWERPC] Fixes to allow use of Ebony's flash chips through physmap_of

This patch contains a handful of small fixes to allow the Ebony's
flash to be exposed as MTD devices via the physmap_of driver.
Specifically it:
	- Makes a small addition to the device tree and zImage wrapper
to record the correct address for the flash in the device tree based
on the board switches as reported via an FPGA register.
	- Prohibits building the old hard-coded "Ebony" flash map on
arch/powerpc kernels, in favour of using physmap_of's device tree
based approach.
	- Enables MTD and physmap_of in the Ebony defconfig.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/boot/dts/ebony.dts

@@ -175,6 +175,7 @@ ir@3,0 {
 				fpga@7,0 {
 					compatible = "Ebony-FPGA";
 					reg = <7 0 10>;
+					virtual-reg = <e8300000>;
 				};
 			};
 

arch/powerpc/boot/ebony.c

@@ -24,6 +24,7 @@
 #include "page.h"
 #include "ops.h"
 #include "reg.h"
+#include "io.h"
 #include "dcr.h"
 #include "44x.h"
 
@@ -92,6 +93,43 @@ void ibm440gp_fixup_clocks(unsigned int sysclk, unsigned int ser_clk)
 	dt_fixup_clock("/plb/opb/serial@40000300", uart1);
 }
 
+#define EBONY_FPGA_PATH		"/plb/opb/ebc/fpga"
+#define	EBONY_FPGA_FLASH_SEL	0x01
+#define EBONY_SMALL_FLASH_PATH	"/plb/opb/ebc/small-flash"
+
+static void ebony_flashsel_fixup(void)
+{
+	void *devp;
+	u32 reg[3] = {0x0, 0x0, 0x80000};
+	u8 *fpga;
+	u8 fpga_reg0 = 0x0;
+
+	devp = finddevice(EBONY_FPGA_PATH);
+	if (!devp)
+		fatal("Couldn't locate FPGA node %s\n\r", EBONY_FPGA_PATH);
+
+	if (getprop(devp, "virtual-reg", &fpga, sizeof(fpga)) != sizeof(fpga))
+		fatal("%s has missing or invalid virtual-reg property\n\r",
+		      EBONY_FPGA_PATH);
+
+	fpga_reg0 = in_8(fpga);
+
+	devp = finddevice(EBONY_SMALL_FLASH_PATH);
+	if (!devp)
+		fatal("Couldn't locate small flash node %s\n\r",
+		      EBONY_SMALL_FLASH_PATH);
+
+	if (getprop(devp, "reg", reg, sizeof(reg)) != sizeof(reg))
+		fatal("%s has reg property of unexpected size\n\r",
+		      EBONY_SMALL_FLASH_PATH);
+
+	/* Invert address bit 14 (IBM-endian) if FLASH_SEL fpga bit is set */
+	if (fpga_reg0 & EBONY_FPGA_FLASH_SEL)
+		reg[1] ^= 0x80000;
+
+	setprop(devp, "reg", reg, sizeof(reg));
+}
+
 static void ebony_fixups(void)
 {
 	// FIXME: sysclk should be derived by reading the FPGA registers
@@ -101,6 +139,7 @@ static void ebony_fixups(void)
 	ibm44x_fixup_memsize();
 	dt_fixup_mac_addresses(ebony_mac0, ebony_mac1);
 	ibm4xx_fixup_ebc_ranges("/plb/opb/ebc");
+	ebony_flashsel_fixup();
 }
 
 void ebony_init(void *mac0, void *mac1)

drivers/mtd/maps/Kconfig

@@ -362,7 +362,7 @@ config MTD_WALNUT
 
 config MTD_EBONY
 	tristate "Flash devices mapped on IBM 440GP Ebony"
-	depends on MTD_JEDECPROBE && EBONY
+	depends on MTD_JEDECPROBE && EBONY && !PPC_MERGE
 	help
 	  This enables access routines for the flash chips on the IBM 440GP
 	  Ebony board. If you have one of these boards and would like to