[ARM] nommu: manage the CP15 things

All the current CP15 access codes in ARM arch can be categorized and
conditioned by the defines as follows:

     Related operation	Safe condition
  a. any CP15 access	!CPU_CP15
  b. alignment trap	CPU_CP15_MMU
  c. D-cache(C-bit)	CPU_CP15
  d. I-cache		CPU_CP15 && !( CPU_ARM610 || CPU_ARM710 ||
				CPU_ARM720 || CPU_ARM740 ||
				CPU_XSCALE || CPU_XSC3 )
  e. alternate vector	CPU_CP15 && !CPU_ARM740
  f. TTB		CPU_CP15_MMU
  g. Domain		CPU_CP15_MMU
  h. FSR/FAR		CPU_CP15_MMU

For example, alternate vector is supported if and only if
"CPU_CP15 && !CPU_ARM740" is satisfied.

Signed-off-by: Hyok S. Choi <hyok.choi@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

9 files changed, 60 insertions, 12 deletions

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 0810d27c039e..2673fee3281c 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -621,6 +621,7 @@ config LEDS_CPU
 
 config ALIGNMENT_TRAP
         bool
+        depends on CPU_CP15_MMU
         default y if !ARCH_EBSA110
         help
           ARM processors can not fetch/store information which is not
@@ -852,7 +853,7 @@ source "drivers/base/Kconfig"
 
 source "drivers/connector/Kconfig"
 
-if ALIGNMENT_TRAP
+if ALIGNMENT_TRAP || !CPU_CP15_MMU
 source "drivers/mtd/Kconfig"
 endif
 
diff --git a/arch/arm/Kconfig-nommu b/arch/arm/Kconfig-nommu
index e1574be2ded6..f087376748d1 100644
--- a/arch/arm/Kconfig-nommu
+++ b/arch/arm/Kconfig-nommu
@@ -25,6 +25,14 @@ config FLASH_SIZE
         hex 'FLASH Size' if SET_MEM_PARAM
         default 0x00400000
 
+config PROCESSOR_ID
+        hex
+        default 0x00007700
+        depends on !CPU_CP15
+        help
+          If processor has no CP15 register, this processor ID is
+          used instead of the auto-probing which utilizes the register.
+
 config REMAP_VECTORS_TO_RAM
         bool 'Install vectors to the begining of RAM' if DRAM_BASE
         depends on DRAM_BASE
diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile
index 2adc1527e0eb..adddc7131685 100644
--- a/arch/arm/boot/compressed/Makefile
+++ b/arch/arm/boot/compressed/Makefile
@@ -51,7 +51,11 @@ OBJS		+= head-at91rm9200.o
 endif
 
 ifeq ($(CONFIG_CPU_BIG_ENDIAN),y)
+ifeq ($(CONFIG_CPU_CP15),y)
 OBJS            += big-endian.o
+else
+# The endian should be set by h/w design.
+endif
 endif
 
 #
diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index 75df1f764a10..e5ab51b9cceb 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -82,9 +82,11 @@
                 kphex   r6, 8           /* processor id */
                 kputc   #':'
                 kphex   r7, 8           /* architecture id */
+#ifdef CONFIG_CPU_CP15
                 kputc   #':'
                 mrc     p15, 0, r0, c1, c0
                 kphex   r0, 8           /* control reg */
+#endif
                 kputc   #'\n'
                 kphex   r5, 8           /* decompressed kernel start */
                 kputc   #'-'
@@ -507,7 +509,11 @@ call_kernel:	bl	cache_clean_flush
  */
 
 call_cache_fn:  adr     r12, proc_types
+#ifdef CONFIG_CPU_CP15
                 mrc     p15, 0, r6, c0, c0      @ get processor ID
+#else
+                ldr     r6, =CONFIG_PROCESSOR_ID
+#endif
 1:              ldr     r1, [r12, #0]           @ get value
                 ldr     r2, [r12, #4]           @ get mask
                 eor     r1, r1, r6              @ (real ^ match)
diff --git a/arch/arm/kernel/head-nommu.S b/arch/arm/kernel/head-nommu.S
index ac9eb3d30518..698a537915dd 100644
--- a/arch/arm/kernel/head-nommu.S
+++ b/arch/arm/kernel/head-nommu.S
@@ -9,7 +9,6 @@
  * published by the Free Software Foundation.
  *
  *  Common kernel startup code (non-paged MM)
- *    for 32-bit CPUs which has a process ID register(CP15).
  *
  */
 #include <linux/linkage.h>
@@ -40,7 +39,11 @@
 ENTRY(stext)
         msr     cpsr_c, #PSR_F_BIT | PSR_I_BIT | SVC_MODE @ ensure svc mode
                                                 @ and irqs disabled
+#ifndef CONFIG_CPU_CP15
+        ldr     r9, =CONFIG_PROCESSOR_ID
+#else
         mrc     p15, 0, r9, c0, c0              @ get processor id
+#endif
         bl      __lookup_processor_type         @ r5=procinfo r9=cpuid
         movs    r10, r5                         @ invalid processor (r5=0)?
         beq     __error_p                               @ yes, error 'p'
@@ -58,6 +61,7 @@ ENTRY(stext)
  */
         .type   __after_proc_init, %function
 __after_proc_init:
+#ifdef CONFIG_CPU_CP15
         mrc     p15, 0, r0, c1, c0, 0           @ read control reg
 #ifdef CONFIG_ALIGNMENT_TRAP
         orr     r0, r0, #CR_A
@@ -74,6 +78,7 @@ __after_proc_init:
         bic     r0, r0, #CR_I
 #endif
         mcr     p15, 0, r0, c1, c0, 0           @ write control reg
+#endif /* CONFIG_CPU_CP15 */
 
         mov     pc, r13                         @ clear the BSS and jump
                                                 @ to start_kernel
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index 3079535afccd..bf35c178a877 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -221,16 +221,26 @@ void __show_regs(struct pt_regs *regs)
                 processor_modes[processor_mode(regs)],
                 thumb_mode(regs) ? " (T)" : "",
                 get_fs() == get_ds() ? "kernel" : "user");
+#if CONFIG_CPU_CP15
         {
-                unsigned int ctrl, transbase, dac;
+                unsigned int ctrl;
                   __asm__ (
                 "       mrc p15, 0, %0, c1, c0\n"
-                "       mrc p15, 0, %1, c2, c0\n"
-                "       mrc p15, 0, %2, c3, c0\n"
-                : "=r" (ctrl), "=r" (transbase), "=r" (dac));
-                printk("Control: %04X  Table: %08X  DAC: %08X\n",
-                        ctrl, transbase, dac);
+                : "=r" (ctrl));
+                printk("Control: %04X\n", ctrl);
         }
+#ifdef CONFIG_CPU_CP15_MMU
+        {
+                unsigned int transbase, dac;
+                  __asm__ (
+                "       mrc p15, 0, %0, c2, c0\n"
+                "       mrc p15, 0, %1, c3, c0\n"
+                : "=r" (transbase), "=r" (dac));
+                printk("Table: %08X  DAC: %08X\n",
+                        transbase, dac);
+        }
+#endif
+#endif
 }
 
 void show_regs(struct pt_regs * regs)
diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig
index c7fb835c148c..0ac11ea84508 100644
--- a/arch/arm/mm/Kconfig
+++ b/arch/arm/mm/Kconfig
@@ -445,15 +445,15 @@ config CPU_BIG_ENDIAN
           of your chipset/board/processor.
 
 config CPU_ICACHE_DISABLE
-        bool "Disable I-Cache"
-        depends on CPU_ARM920T || CPU_ARM922T || CPU_ARM925T || CPU_ARM926T || CPU_ARM1020 || CPU_V6
+        bool "Disable I-Cache (I-bit)"
+        depends on CPU_CP15 && !(CPU_ARM610 || CPU_ARM710 || CPU_ARM720T || CPU_ARM740T || CPU_XSCALE || CPU_XSC3)
         help
           Say Y here to disable the processor instruction cache. Unless
           you have a reason not to or are unsure, say N.
 
 config CPU_DCACHE_DISABLE
-        bool "Disable D-Cache"
-        depends on CPU_ARM920T || CPU_ARM922T || CPU_ARM925T || CPU_ARM926T || CPU_ARM1020 || CPU_V6
+        bool "Disable D-Cache (C-bit)"
+        depends on CPU_CP15
         help
           Say Y here to disable the processor data cache. Unless
           you have a reason not to or are unsure, say N.
diff --git a/arch/arm/mm/cache-v4.S b/arch/arm/mm/cache-v4.S
index b8ad5d58ebe2..b2908063ed6a 100644
--- a/arch/arm/mm/cache-v4.S
+++ b/arch/arm/mm/cache-v4.S
@@ -29,9 +29,13 @@ ENTRY(v4_flush_user_cache_all)
  *      Clean and invalidate the entire cache.
  */
 ENTRY(v4_flush_kern_cache_all)
+#ifdef CPU_CP15
         mov     r0, #0
         mcr     p15, 0, r0, c7, c7, 0           @ flush ID cache
         mov     pc, lr
+#else
+        /* FALLTHROUGH */
+#endif
 
 /*
  *      flush_user_cache_range(start, end, flags)
@@ -44,9 +48,13 @@ ENTRY(v4_flush_kern_cache_all)
  *      - flags - vma_area_struct flags describing address space
  */
 ENTRY(v4_flush_user_cache_range)
+#ifdef CPU_CP15
         mov     ip, #0
         mcreq   p15, 0, ip, c7, c7, 0           @ flush ID cache
         mov     pc, lr
+#else
+        /* FALLTHROUGH */
+#endif
 
 /*
  *      coherent_kern_range(start, end)
@@ -108,8 +116,10 @@ ENTRY(v4_dma_inv_range)
  *      - end    - virtual end address
  */
 ENTRY(v4_dma_flush_range)
+#ifdef CPU_CP15
         mov     r0, #0
         mcr     p15, 0, r0, c7, c7, 0           @ flush ID cache
+#endif
         /* FALLTHROUGH */
 
 /*
diff --git a/include/asm-arm/system.h b/include/asm-arm/system.h
index c19c5b009f71..f05fbe31576c 100644
--- a/include/asm-arm/system.h
+++ b/include/asm-arm/system.h
@@ -46,6 +46,7 @@
 #define CPUID_TCM       2
 #define CPUID_TLBTYPE   3
 
+#ifdef CONFIG_CPU_CP15
 #define read_cpuid(reg)                                                 \
         ({                                                              \
                 unsigned int __val;                                     \
@@ -55,6 +56,9 @@
                     : "cc");                                            \
                 __val;                                                  \
         })
+#else
+#define read_cpuid(reg) (processor_id)
+#endif
 
 /*
  * This is used to ensure the compiler did actually allocate the register we