[ARM] cputype: separate definitions, use them

Add asm/cputype.h, moving functions and definitions from asm/system.h
there.  Convert all users of 'processor_id' to the more efficient
read_cpuid_id() function.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

18 files changed, 131 insertions, 114 deletions

diff --git a/arch/arm/include/asm/cputype.h b/arch/arm/include/asm/cputype.h
new file mode 100644
index 0000000..7b9d27e
--- /dev/null
+++ b/arch/arm/include/asm/cputype.h
@@ -0,0 +1,64 @@
+#ifndef __ASM_ARM_CPUTYPE_H
+#define __ASM_ARM_CPUTYPE_H
+
+#include <linux/stringify.h>
+
+#define CPUID_ID	0
+#define CPUID_CACHETYPE	1
+#define CPUID_TCM	2
+#define CPUID_TLBTYPE	3
+
+#ifdef CONFIG_CPU_CP15
+#define read_cpuid(reg)							\
+	({								\
+		unsigned int __val;					\
+		asm("mrc	p15, 0, %0, c0, c0, " __stringify(reg)	\
+		    : "=r" (__val)					\
+		    :							\
+		    : "cc");						\
+		__val;							\
+	})
+#else
+extern unsigned int processor_id;
+#define read_cpuid(reg) (processor_id)
+#endif
+
+/*
+ * The CPU ID never changes at run time, so we might as well tell the
+ * compiler that it's constant.  Use this function to read the CPU ID
+ * rather than directly reading processor_id or read_cpuid() directly.
+ */
+static inline unsigned int __attribute_const__ read_cpuid_id(void)
+{
+	return read_cpuid(CPUID_ID);
+}
+
+static inline unsigned int __attribute_const__ read_cpuid_cachetype(void)
+{
+	return read_cpuid(CPUID_CACHETYPE);
+}
+
+/*
+ * Intel's XScale3 core supports some v6 features (supersections, L2)
+ * but advertises itself as v5 as it does not support the v6 ISA.  For
+ * this reason, we need a way to explicitly test for this type of CPU.
+ */
+#ifndef CONFIG_CPU_XSC3
+#define cpu_is_xsc3()	0
+#else
+static inline int cpu_is_xsc3(void)
+{
+	if ((read_cpuid_id() & 0xffffe000) == 0x69056000)
+		return 1;
+
+	return 0;
+}
+#endif
+
+#if !defined(CONFIG_CPU_XSCALE) && !defined(CONFIG_CPU_XSC3)
+#define	cpu_is_xscale()	0
+#else
+#define	cpu_is_xscale()	1
+#endif
+
+#endif
diff --git a/arch/arm/include/asm/system.h b/arch/arm/include/asm/system.h
index 514af79..7aad784 100644
--- a/arch/arm/include/asm/system.h
+++ b/arch/arm/include/asm/system.h
@@ -43,11 +43,6 @@
 #define CR_XP	(1 << 23)	/* Extended page tables			*/
 #define CR_VE	(1 << 24)	/* Vectored interrupts			*/
 
-#define CPUID_ID	0
-#define CPUID_CACHETYPE	1
-#define CPUID_TCM	2
-#define CPUID_TLBTYPE	3
-
 /*
  * This is used to ensure the compiler did actually allocate the register we
  * asked it for some inline assembly sequences.  Apparently we can't trust
@@ -61,36 +56,8 @@
 #ifndef __ASSEMBLY__
 
 #include <linux/linkage.h>
-#include <linux/stringify.h>
 #include <linux/irqflags.h>
 
-#ifdef CONFIG_CPU_CP15
-#define read_cpuid(reg)							\
-	({								\
-		unsigned int __val;					\
-		asm("mrc	p15, 0, %0, c0, c0, " __stringify(reg)	\
-		    : "=r" (__val)					\
-		    :							\
-		    : "cc");						\
-		__val;							\
-	})
-#else
-extern unsigned int processor_id;
-#define read_cpuid(reg) (processor_id)
-#endif
-
-/*
- * The CPU ID never changes at run time, so we might as well tell the
- * compiler that it's constant.  Use this function to read the CPU ID
- * rather than directly reading processor_id or read_cpuid() directly.
- */
-static inline unsigned int read_cpuid_id(void) __attribute_const__;
-
-static inline unsigned int read_cpuid_id(void)
-{
-	return read_cpuid(CPUID_ID);
-}
-
 #define __exception	__attribute__((section(".exception.text")))
 
 struct thread_info;
@@ -131,31 +98,6 @@ extern void cpu_init(void);
 void arm_machine_restart(char mode);
 extern void (*arm_pm_restart)(char str);
 
-/*
- * Intel's XScale3 core supports some v6 features (supersections, L2)
- * but advertises itself as v5 as it does not support the v6 ISA.  For
- * this reason, we need a way to explicitly test for this type of CPU.
- */
-#ifndef CONFIG_CPU_XSC3
-#define cpu_is_xsc3()	0
-#else
-static inline int cpu_is_xsc3(void)
-{
-	extern unsigned int processor_id;
-
-	if ((processor_id & 0xffffe000) == 0x69056000)
-		return 1;
-
-	return 0;
-}
-#endif
-
-#if !defined(CONFIG_CPU_XSCALE) && !defined(CONFIG_CPU_XSC3)
-#define	cpu_is_xscale()	0
-#else
-#define	cpu_is_xscale()	1
-#endif
-
 #define UDBG_UNDEFINED	(1 << 0)
 #define UDBG_SYSCALL	(1 << 1)
 #define UDBG_BADABORT	(1 << 2)
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 2ca7038..fb04703 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -26,6 +26,7 @@
 #include <linux/fs.h>
 
 #include <asm/cpu.h>
+#include <asm/cputype.h>
 #include <asm/elf.h>
 #include <asm/procinfo.h>
 #include <asm/setup.h>
@@ -280,9 +281,9 @@ static inline void dump_cache(const char *prefix, int cpu, unsigned int cache)
 
 static void __init dump_cpu_info(int cpu)
 {
-	unsigned int info = read_cpuid(CPUID_CACHETYPE);
+	unsigned int info = read_cpuid_cachetype();
 
-	if (info != processor_id) {
+	if (info != read_cpuid_id()) {
 		printk("CPU%u: D %s %s cache\n", cpu, cache_is_vivt() ? "VIVT" : "VIPT",
 		       cache_types[CACHE_TYPE(info)]);
 		if (CACHE_S(info)) {
@@ -301,15 +302,15 @@ int cpu_architecture(void)
 {
 	int cpu_arch;
 
-	if ((processor_id & 0x0008f000) == 0) {
+	if ((read_cpuid_id() & 0x0008f000) == 0) {
 		cpu_arch = CPU_ARCH_UNKNOWN;
-	} else if ((processor_id & 0x0008f000) == 0x00007000) {
-		cpu_arch = (processor_id & (1 << 23)) ? CPU_ARCH_ARMv4T : CPU_ARCH_ARMv3;
-	} else if ((processor_id & 0x00080000) == 0x00000000) {
-		cpu_arch = (processor_id >> 16) & 7;
+	} else if ((read_cpuid_id() & 0x0008f000) == 0x00007000) {
+		cpu_arch = (read_cpuid_id() & (1 << 23)) ? CPU_ARCH_ARMv4T : CPU_ARCH_ARMv3;
+	} else if ((read_cpuid_id() & 0x00080000) == 0x00000000) {
+		cpu_arch = (read_cpuid_id() >> 16) & 7;
 		if (cpu_arch)
 			cpu_arch += CPU_ARCH_ARMv3;
-	} else if ((processor_id & 0x000f0000) == 0x000f0000) {
+	} else if ((read_cpuid_id() & 0x000f0000) == 0x000f0000) {
 		unsigned int mmfr0;
 
 		/* Revised CPUID format. Read the Memory Model Feature
@@ -346,10 +347,10 @@ static void __init setup_processor(void)
 	 * types.  The linker builds this table for us from the
 	 * entries in arch/arm/mm/proc-*.S
 	 */
-	list = lookup_processor_type(processor_id);
+	list = lookup_processor_type(read_cpuid_id());
 	if (!list) {
 		printk("CPU configuration botched (ID %08x), unable "
-		       "to continue.\n", processor_id);
+		       "to continue.\n", read_cpuid_id());
 		while (1);
 	}
 
@@ -369,7 +370,7 @@ static void __init setup_processor(void)
 #endif
 
 	printk("CPU: %s [%08x] revision %d (ARMv%s), cr=%08lx\n",
-	       cpu_name, processor_id, (int)processor_id & 15,
+	       cpu_name, read_cpuid_id(), read_cpuid_id() & 15,
 	       proc_arch[cpu_architecture()], cr_alignment);
 
 	sprintf(init_utsname()->machine, "%s%c", list->arch_name, ENDIANNESS);
@@ -922,7 +923,7 @@ static int c_show(struct seq_file *m, void *v)
 	int i;
 
 	seq_printf(m, "Processor\t: %s rev %d (%s)\n",
-		   cpu_name, (int)processor_id & 15, elf_platform);
+		   cpu_name, read_cpuid_id() & 15, elf_platform);
 
 #if defined(CONFIG_SMP)
 	for_each_online_cpu(i) {
@@ -949,30 +950,30 @@ static int c_show(struct seq_file *m, void *v)
 		if (elf_hwcap & (1 << i))
 			seq_printf(m, "%s ", hwcap_str[i]);
 
-	seq_printf(m, "\nCPU implementer\t: 0x%02x\n", processor_id >> 24);
+	seq_printf(m, "\nCPU implementer\t: 0x%02x\n", read_cpuid_id() >> 24);
 	seq_printf(m, "CPU architecture: %s\n", proc_arch[cpu_architecture()]);
 
-	if ((processor_id & 0x0008f000) == 0x00000000) {
+	if ((read_cpuid_id() & 0x0008f000) == 0x00000000) {
 		/* pre-ARM7 */
-		seq_printf(m, "CPU part\t: %07x\n", processor_id >> 4);
+		seq_printf(m, "CPU part\t: %07x\n", read_cpuid_id() >> 4);
 	} else {
-		if ((processor_id & 0x0008f000) == 0x00007000) {
+		if ((read_cpuid_id() & 0x0008f000) == 0x00007000) {
 			/* ARM7 */
 			seq_printf(m, "CPU variant\t: 0x%02x\n",
-				   (processor_id >> 16) & 127);
+				   (read_cpuid_id() >> 16) & 127);
 		} else {
 			/* post-ARM7 */
 			seq_printf(m, "CPU variant\t: 0x%x\n",
-				   (processor_id >> 20) & 15);
+				   (read_cpuid_id() >> 20) & 15);
 		}
 		seq_printf(m, "CPU part\t: 0x%03x\n",
-			   (processor_id >> 4) & 0xfff);
+			   (read_cpuid_id() >> 4) & 0xfff);
 	}
-	seq_printf(m, "CPU revision\t: %d\n", processor_id & 15);
+	seq_printf(m, "CPU revision\t: %d\n", read_cpuid_id() & 15);
 
 	{
-		unsigned int cache_info = read_cpuid(CPUID_CACHETYPE);
-		if (cache_info != processor_id) {
+		unsigned int cache_info = read_cpuid_cachetype();
+		if (cache_info != read_cpuid_id()) {
 			seq_printf(m, "Cache type\t: %s\n"
 				      "Cache clean\t: %s\n"
 				      "Cache lockdown\t: %s\n"
diff --git a/arch/arm/mach-iop32x/iq31244.c b/arch/arm/mach-iop32x/iq31244.c
index 082818aa..1845643 100644
--- a/arch/arm/mach-iop32x/iq31244.c
+++ b/arch/arm/mach-iop32x/iq31244.c
@@ -27,6 +27,7 @@
 #include <linux/mtd/physmap.h>
 #include <linux/platform_device.h>
 #include <mach/hardware.h>
+#include <asm/cputype.h>
 #include <asm/io.h>
 #include <asm/irq.h>
 #include <asm/mach/arch.h>
@@ -49,8 +50,7 @@ static int force_ep80219;
 
 static int is_80219(void)
 {
-	extern int processor_id;
-	return !!((processor_id & 0xffffffe0) == 0x69052e20);
+	return !!((read_cpuid_id() & 0xffffffe0) == 0x69052e20);
 }
 
 static int is_ep80219(void)
diff --git a/arch/arm/mach-ixp4xx/common-pci.c b/arch/arm/mach-ixp4xx/common-pci.c
index 192538a..f74a460 100644
--- a/arch/arm/mach-ixp4xx/common-pci.c
+++ b/arch/arm/mach-ixp4xx/common-pci.c
@@ -27,6 +27,7 @@
 #include <linux/device.h>
 #include <asm/dma-mapping.h>
 
+#include <asm/cputype.h>
 #include <asm/io.h>
 #include <asm/irq.h>
 #include <asm/sizes.h>
@@ -366,15 +367,13 @@ void __init ixp4xx_adjust_zones(int node, unsigned long *zone_size,
 
 void __init ixp4xx_pci_preinit(void)
 {  
-	unsigned long processor_id;
-
-	asm("mrc p15, 0, %0, cr0, cr0, 0;" : "=r"(processor_id) :);
+	unsigned long cpuid = read_cpuid_id();
 
 	/*
 	 * Determine which PCI read method to use.
 	 * Rev 0 IXP425 requires workaround.
 	 */
-	if (!(processor_id & 0xf) && cpu_is_ixp42x()) {
+	if (!(cpuid & 0xf) && cpu_is_ixp42x()) {
 		printk("PCI: IXP42x A0 silicon detected - "
 			"PCI Non-Prefetch Workaround Enabled\n");
 		ixp4xx_pci_read = ixp4xx_pci_read_errata;
diff --git a/arch/arm/mach-ixp4xx/include/mach/cpu.h b/arch/arm/mach-ixp4xx/include/mach/cpu.h
index ff8aa23..51bd69c 100644
--- a/arch/arm/mach-ixp4xx/include/mach/cpu.h
+++ b/arch/arm/mach-ixp4xx/include/mach/cpu.h
@@ -14,18 +14,19 @@
 #ifndef __ASM_ARCH_CPU_H__
 #define __ASM_ARCH_CPU_H__
 
-extern unsigned int processor_id;
+#include <asm/cputype.h>
+
 /* Processor id value in CP15 Register 0 */
 #define IXP425_PROCESSOR_ID_VALUE	0x690541c0
 #define IXP435_PROCESSOR_ID_VALUE	0x69054040
 #define IXP465_PROCESSOR_ID_VALUE	0x69054200
 #define IXP4XX_PROCESSOR_ID_MASK	0xfffffff0
 
-#define cpu_is_ixp42x()	((processor_id & IXP4XX_PROCESSOR_ID_MASK) == \
+#define cpu_is_ixp42x()	((read_cpuid_id() & IXP4XX_PROCESSOR_ID_MASK) == \
 			  IXP425_PROCESSOR_ID_VALUE)
-#define cpu_is_ixp43x()	((processor_id & IXP4XX_PROCESSOR_ID_MASK) == \
+#define cpu_is_ixp43x()	((read_cpuid_id() & IXP4XX_PROCESSOR_ID_MASK) == \
 			  IXP435_PROCESSOR_ID_VALUE)
-#define cpu_is_ixp46x()	((processor_id & IXP4XX_PROCESSOR_ID_MASK) == \
+#define cpu_is_ixp46x()	((read_cpuid_id() & IXP4XX_PROCESSOR_ID_MASK) == \
 			  IXP465_PROCESSOR_ID_VALUE)
 
 static inline u32 ixp4xx_read_feature_bits(void)
diff --git a/arch/arm/mach-omap2/id.c b/arch/arm/mach-omap2/id.c
index a5d4526..2fd8a2d 100644
--- a/arch/arm/mach-omap2/id.c
+++ b/arch/arm/mach-omap2/id.c
@@ -15,6 +15,7 @@
 #include <linux/kernel.h>
 #include <linux/init.h>
 
+#include <asm/cputype.h>
 #include <asm/io.h>
 
 #include <mach/control.h>
diff --git a/arch/arm/mach-pxa/include/mach/hardware.h b/arch/arm/mach-pxa/include/mach/hardware.h
index e89df4d..a1a0a2f 100644
--- a/arch/arm/mach-pxa/include/mach/hardware.h
+++ b/arch/arm/mach-pxa/include/mach/hardware.h
@@ -62,6 +62,8 @@
 
 #ifndef __ASSEMBLY__
 
+#include <asm/cputype.h>
+
 #ifdef CONFIG_PXA25x
 #define __cpu_is_pxa21x(id)				\
 	({						\
diff --git a/arch/arm/mach-sa1100/cpu-sa1100.c b/arch/arm/mach-sa1100/cpu-sa1100.c
index da3a898..f7fa0347 100644
--- a/arch/arm/mach-sa1100/cpu-sa1100.c
+++ b/arch/arm/mach-sa1100/cpu-sa1100.c
@@ -88,6 +88,8 @@
 #include <linux/init.h>
 #include <linux/cpufreq.h>
 
+#include <asm/cputype.h>
+
 #include <mach/hardware.h>
 
 #include "generic.h"
@@ -240,7 +242,7 @@ static struct cpufreq_driver sa1100_driver = {
 
 static int __init sa1100_dram_init(void)
 {
- 	if ((processor_id & CPU_SA1100_MASK) == CPU_SA1100_ID)
+	if (cpu_is_sa1100())
 		return cpufreq_register_driver(&sa1100_driver);
 	else
 		return -ENODEV;
diff --git a/arch/arm/mach-sa1100/cpu-sa1110.c b/arch/arm/mach-sa1100/cpu-sa1110.c
index 029dbfb..78d8294 100644
--- a/arch/arm/mach-sa1100/cpu-sa1110.c
+++ b/arch/arm/mach-sa1100/cpu-sa1110.c
@@ -25,6 +25,7 @@
 #include <linux/init.h>
 
 #include <mach/hardware.h>
+#include <asm/cputype.h>
 #include <asm/mach-types.h>
 #include <asm/io.h>
 #include <asm/system.h>
diff --git a/arch/arm/mach-sa1100/include/mach/SA-1100.h b/arch/arm/mach-sa1100/include/mach/SA-1100.h
index 62aaf04..4f7ea01 100644
--- a/arch/arm/mach-sa1100/include/mach/SA-1100.h
+++ b/arch/arm/mach-sa1100/include/mach/SA-1100.h
@@ -2054,19 +2054,3 @@
                 	        	/* active display mode)            */
 #define LCCR3_OutEnH	(LCCR3_OEP*0)	/*  Output Enable active High      */
 #define LCCR3_OutEnL	(LCCR3_OEP*1)	/*  Output Enable active Low       */
-
-#ifndef __ASSEMBLY__
-extern unsigned int processor_id;
-#endif
-
-#define CPU_REVISION	(processor_id & 15)
-#define CPU_SA1110_A0	(0)
-#define CPU_SA1110_B0	(4)
-#define CPU_SA1110_B1	(5)
-#define CPU_SA1110_B2	(6)
-#define CPU_SA1110_B4	(8)
-
-#define CPU_SA1100_ID	(0x4401a110)
-#define CPU_SA1100_MASK	(0xfffffff0)
-#define CPU_SA1110_ID	(0x6901b110)
-#define CPU_SA1110_MASK	(0xfffffff0)
diff --git a/arch/arm/mach-sa1100/include/mach/hardware.h b/arch/arm/mach-sa1100/include/mach/hardware.h
index 5976435..b70846c 100644
--- a/arch/arm/mach-sa1100/include/mach/hardware.h
+++ b/arch/arm/mach-sa1100/include/mach/hardware.h
@@ -36,8 +36,26 @@
 #define io_v2p( x )             \
    ( (((x)&0x00ffffff) | (((x)&(0x30000000>>VIO_SHIFT))<<VIO_SHIFT)) + PIO_START )
 
+#define CPU_SA1110_A0	(0)
+#define CPU_SA1110_B0	(4)
+#define CPU_SA1110_B1	(5)
+#define CPU_SA1110_B2	(6)
+#define CPU_SA1110_B4	(8)
+
+#define CPU_SA1100_ID	(0x4401a110)
+#define CPU_SA1100_MASK	(0xfffffff0)
+#define CPU_SA1110_ID	(0x6901b110)
+#define CPU_SA1110_MASK	(0xfffffff0)
+
 #ifndef __ASSEMBLY__
 
+#include <asm/cputype.h>
+
+#define CPU_REVISION	(read_cpuid_id() & 15)
+
+#define cpu_is_sa1100()	((read_cpuid_id() & CPU_SA1100_MASK) == CPU_SA1100_ID)
+#define cpu_is_sa1110()	((read_cpuid_id() & CPU_SA1110_MASK) == CPU_SA1110_ID)
+
 # define __REG(x)	(*((volatile unsigned long *)io_p2v(x)))
 # define __PREG(x)	(io_v2p((unsigned long)&(x)))
 
diff --git a/arch/arm/mm/cache-xsc3l2.c b/arch/arm/mm/cache-xsc3l2.c
index 158bd96..10b1bae 100644
--- a/arch/arm/mm/cache-xsc3l2.c
+++ b/arch/arm/mm/cache-xsc3l2.c
@@ -18,10 +18,11 @@
  */
 #include <linux/init.h>
 #include <linux/spinlock.h>
+#include <linux/io.h>
 
 #include <asm/system.h>
+#include <asm/cputype.h>
 #include <asm/cacheflush.h>
-#include <asm/io.h>
 
 #define CR_L2	(1 << 26)
 
diff --git a/arch/arm/mm/ioremap.c b/arch/arm/mm/ioremap.c
index b81dbf9..20e4454e 100644
--- a/arch/arm/mm/ioremap.c
+++ b/arch/arm/mm/ioremap.c
@@ -25,6 +25,7 @@
 #include <linux/mm.h>
 #include <linux/vmalloc.h>
 
+#include <asm/cputype.h>
 #include <asm/cacheflush.h>
 #include <asm/io.h>
 #include <asm/mmu_context.h>
diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c
index 3f6dc40..28ead83 100644
--- a/arch/arm/mm/mmap.c
+++ b/arch/arm/mm/mmap.c
@@ -6,6 +6,7 @@
 #include <linux/mman.h>
 #include <linux/shm.h>
 #include <linux/sched.h>
+#include <asm/cputype.h>
 #include <asm/system.h>
 
 #define COLOUR_ALIGN(addr,pgoff)		\
@@ -37,8 +38,8 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
 	 * caches alias.  This is indicated by bits 9 and 21 of the
 	 * cache type register.
 	 */
-	cache_type = read_cpuid(CPUID_CACHETYPE);
-	if (cache_type != read_cpuid(CPUID_ID)) {
+	cache_type = read_cpuid_cachetype();
+	if (cache_type != read_cpuid_id()) {
 		aliasing = (cache_type | cache_type >> 12) & (1 << 11);
 		if (aliasing)
 			do_align = filp || flags & MAP_SHARED;
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 25d9a11..c2bbe3f 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -15,6 +15,7 @@
 #include <linux/mman.h>
 #include <linux/nodemask.h>
 
+#include <asm/cputype.h>
 #include <asm/mach-types.h>
 #include <asm/setup.h>
 #include <asm/sizes.h>
diff --git a/arch/arm/oprofile/op_model_xscale.c b/arch/arm/oprofile/op_model_xscale.c
index 7c3289c..724ab9c 100644
--- a/arch/arm/oprofile/op_model_xscale.c
+++ b/arch/arm/oprofile/op_model_xscale.c
@@ -22,7 +22,7 @@
 #include <linux/interrupt.h>
 #include <linux/irq.h>
 
-#include <asm/system.h>
+#include <asm/cputype.h>
 
 #include "op_counter.h"
 #include "op_arm_model.h"
diff --git a/drivers/watchdog/ixp4xx_wdt.c b/drivers/watchdog/ixp4xx_wdt.c
index 8302ef0..147b4d5 100644
--- a/drivers/watchdog/ixp4xx_wdt.c
+++ b/drivers/watchdog/ixp4xx_wdt.c
@@ -174,10 +174,8 @@ static struct miscdevice ixp4xx_wdt_miscdev = {
 static int __init ixp4xx_wdt_init(void)
 {
 	int ret;
-	unsigned long processor_id;
 
-	asm("mrc p15, 0, %0, cr0, cr0, 0;" : "=r"(processor_id) :);
-	if (!(processor_id & 0xf) && !cpu_is_ixp46x()) {
+	if (!(read_cpuid_id() & 0xf) && !cpu_is_ixp46x()) {
 		printk(KERN_ERR "IXP4XXX Watchdog: Rev. A0 IXP42x CPU detected"
 			" - watchdog disabled\n");