powerpc: Partialy restore core of mpc8xx

CS Systemes d'Information (CSSI) manufactures 8xx boards for
critical communication systems. Those boards have been
running U-Boot since 2010 and will have to be maintained
until at least 2027.

commit 5b8e76c35ec312a3f73126bd1a2d2c0965b98a9f
("powerpc, 8xx: remove support for 8xx") orphaned those boards
by removing support for the mpc8xx CPU.

This commit partially restores support for the 8xx, with the
following limitations:
- Restores support for MPC866 and MPC885 only
- Does not restore IDE, PCMCIA, I2C, USB
- Does not restore examples
- Does not restore POST
- Does not restore Ethernet on SCC
- Does not restore console on SCC
- Does not restore bedbug and kgdb support

As the 866 and 885 do not support the following features,
they are not restored either:
- VIDEO / LCD
- RTC clock

The CPM uCODE patch is not restored either, because:
- 866 and 885 already have support for I2C and SPI relocation
without a uCODE patch
- relocation of SMC, I2C or SPI is only needed for using SCCs
for Ethernet or QMC

The dynamic setup/calculation of clocks is removed, we
expect the target being use with the clock and PLPRCR register
defined in the configuration.
All the clock settings for 8xx prior to 866 is removed as
well as we now only support 866 and 885.

This code is mature and addresses mature boards. Therefore
all code enclosed in '#if 0/#endif' and '#if XX_DEBUG/#endif'
is unneeded.

The following files are not restored by this patch:

- arch/powerpc/cpu/mpc8xx/bedbug_860.c
- arch/powerpc/cpu/mpc8xx/fec.h
- arch/powerpc/cpu/mpc8xx/kgdb.S
- arch/powerpc/cpu/mpc8xx/plprcr_write.S
- arch/powerpc/cpu/mpc8xx/scc.c
- arch/powerpc/cpu/mpc8xx/upatch.c
- arch/powerpc/cpu/mpc8xx/video.c
- arch/powerpc/include/asm/status_led.h
- arch/powerpc/lib/ide.c
- arch/powerpc/lib/ide.h
- doc/README.MPC866
- drivers/pcmcia/mpc8xx_pcmcia.c
- drivers/rtc/mpc8xx.c
- drivers/usb/gadget/mpc8xx_udc.c
- drivers/video/mpc8xx_lcd.c
- examples/standalone/test_burst.c
- examples/standalone/test_burst.h
- examples/standalone/test_burst_lib.S
- examples/standalone/timer.c
- include/mpc823_lcd.h
- include/usb/mpc8xx_udc.h
- post/cpu/mpc8xx/Makefile
- post/cpu/mpc8xx/cache.c
- post/cpu/mpc8xx/cache_8xx.S
- post/cpu/mpc8xx/ether.c
- post/cpu/mpc8xx/spr.c
- post/cpu/mpc8xx/uart.c
- post/cpu/mpc8xx/usb.c
- post/cpu/mpc8xx/watchdog.c

Some of the restored files are not located in a proper location.
In order to keep traceability of the changes, they will be
moved to their correct location and moved to Kconfig in a
followup patch.

This patch also declares CSSI as point of contact for the update
of the 8xx platform, as those boards are the only ones still
being maintained on the 8xx area. A later patch will add
those boards to the tree.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
diff --git a/arch/powerpc/include/asm/cache.h b/arch/powerpc/include/asm/cache.h
index 20c52fc..d3a8391 100644
--- a/arch/powerpc/include/asm/cache.h
+++ b/arch/powerpc/include/asm/cache.h
@@ -7,7 +7,9 @@
 #include <asm/processor.h>
 
 /* bytes per L1 cache line */
-#if defined(CONFIG_PPC64BRIDGE)
+#if defined(CONFIG_8xx)
+#define	L1_CACHE_SHIFT	4
+#elif defined(CONFIG_PPC64BRIDGE)
 #define L1_CACHE_SHIFT	7
 #elif defined(CONFIG_E500MC)
 #define L1_CACHE_SHIFT	6
@@ -70,4 +72,41 @@
 #define L2CACHE_NONE	0x03	/* NONE */
 #define L2CACHE_PARITY  0x08    /* Mask for L2 Cache Parity Protected bit */
 
+#ifdef CONFIG_8xx
+/* Cache control on the MPC8xx is provided through some additional
+ * special purpose registers.
+ */
+#define IC_CST		560	/* Instruction cache control/status */
+#define IC_ADR		561	/* Address needed for some commands */
+#define IC_DAT		562	/* Read-only data register */
+#define DC_CST		568	/* Data cache control/status */
+#define DC_ADR		569	/* Address needed for some commands */
+#define DC_DAT		570	/* Read-only data register */
+
+/* Commands.  Only the first few are available to the instruction cache.
+*/
+#define	IDC_ENABLE	0x02000000	/* Cache enable */
+#define IDC_DISABLE	0x04000000	/* Cache disable */
+#define IDC_LDLCK	0x06000000	/* Load and lock */
+#define IDC_UNLINE	0x08000000	/* Unlock line */
+#define IDC_UNALL	0x0a000000	/* Unlock all */
+#define IDC_INVALL	0x0c000000	/* Invalidate all */
+
+#define DC_FLINE	0x0e000000	/* Flush data cache line */
+#define DC_SFWT		0x01000000	/* Set forced writethrough mode */
+#define DC_CFWT		0x03000000	/* Clear forced writethrough mode */
+#define DC_SLES		0x05000000	/* Set little endian swap mode */
+#define DC_CLES		0x07000000	/* Clear little endian swap mode */
+
+/* Status.
+*/
+#define IDC_ENABLED	0x80000000	/* Cache is enabled */
+#define IDC_CERR1	0x00200000	/* Cache error 1 */
+#define IDC_CERR2	0x00100000	/* Cache error 2 */
+#define IDC_CERR3	0x00080000	/* Cache error 3 */
+
+#define DC_DFWT		0x40000000	/* Data cache is forced write through */
+#define DC_LES		0x20000000	/* Caches are little endian mode */
+#endif /* CONFIG_8xx */
+
 #endif