ARC: Cache Flush Management

* ARC700 has VIPT L1 Caches
* Caches don't snoop and are not coherent
* Given the PAGE_SIZE and Cache associativity, we don't support aliasing
  D$ configurations (yet), but do allow aliasing I$ configs
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

arch/arc/include/asm/arcregs.h

@@ -58,6 +58,33 @@
 #define TIMER_CTRL_IE		(1 << 0) /* Interupt when Count reachs limit */
 #define TIMER_CTRL_NH		(1 << 1) /* Count only when CPU NOT halted */
 
+/* Instruction cache related Auxiliary registers */
+#define ARC_REG_IC_BCR		0x77	/* Build Config reg */
+#define ARC_REG_IC_IVIC		0x10
+#define ARC_REG_IC_CTRL		0x11
+#define ARC_REG_IC_IVIL		0x19
+#if (CONFIG_ARC_MMU_VER > 2)
+#define ARC_REG_IC_PTAG		0x1E
+#endif
+
+/* Bit val in IC_CTRL */
+#define IC_CTRL_CACHE_DISABLE   0x1
+
+/* Data cache related Auxiliary registers */
+#define ARC_REG_DC_BCR		0x72
+#define ARC_REG_DC_IVDC		0x47
+#define ARC_REG_DC_CTRL		0x48
+#define ARC_REG_DC_IVDL		0x4A
+#define ARC_REG_DC_FLSH		0x4B
+#define ARC_REG_DC_FLDL		0x4C
+#if (CONFIG_ARC_MMU_VER > 2)
+#define ARC_REG_DC_PTAG		0x5C
+#endif
+
+/* Bit val in DC_CTRL */
+#define DC_CTRL_INV_MODE_FLUSH  0x40
+#define DC_CTRL_FLUSH_STATUS    0x100
+
 /*
  * Floating Pt Registers
  * Status regs are read-only (build-time) so need not be saved/restored
@@ -132,6 +159,31 @@
 
 #endif
 
+#define READ_BCR(reg, into)				\
+{							\
+	unsigned int tmp;				\
+	tmp = read_aux_reg(reg);			\
+	if (sizeof(tmp) == sizeof(into)) {		\
+		into = *((typeof(into) *)&tmp);		\
+	} else {					\
+		extern void bogus_undefined(void);	\
+		bogus_undefined();			\
+	}						\
+}
+
+#define WRITE_BCR(reg, into)				\
+{							\
+	unsigned int tmp;				\
+	if (sizeof(tmp) == sizeof(into)) {		\
+		tmp = (*(unsigned int *)(into));	\
+		write_aux_reg(reg, tmp);		\
+	} else  {					\
+		extern void bogus_undefined(void);	\
+		bogus_undefined();			\
+	}						\
+}
+
+
 #ifdef CONFIG_ARC_FPU_SAVE_RESTORE
 /* These DPFP regs need to be saved/restored across ctx-sw */
 struct arc_fpu {
@@ -141,6 +193,34 @@ struct arc_fpu {
 };
 #endif
 
+/*
+ ***************************************************************
+ * Build Configuration Registers, with encoded hardware config
+ */
+
+struct bcr_cache {
+#ifdef CONFIG_CPU_BIG_ENDIAN
+	unsigned int pad:12, line_len:4, sz:4, config:4, ver:8;
+#else
+	unsigned int ver:8, config:4, sz:4, line_len:4, pad:12;
+#endif
+};
+
+/*
+ *******************************************************************
+ * Generic structures to hold build configuration used at runtime
+ */
+
+struct cpuinfo_arc_cache {
+	unsigned int has_aliasing, sz, line_len, assoc, ver;
+};
+
+struct cpuinfo_arc {
+	struct cpuinfo_arc_cache icache, dcache;
+};
+
+extern struct cpuinfo_arc cpuinfo_arc700[];
+
 #endif /* __ASEMBLY__ */
 
 #endif /* __KERNEL__ */

arch/arc/include/asm/cache.h

@@ -18,4 +18,58 @@
 
 #define L1_CACHE_BYTES		(1 << L1_CACHE_SHIFT)
 
+#define ARC_ICACHE_WAYS	2
+#define ARC_DCACHE_WAYS	4
+
+/* Helpers */
+#define ARC_ICACHE_LINE_LEN	L1_CACHE_BYTES
+#define ARC_DCACHE_LINE_LEN	L1_CACHE_BYTES
+
+#define ICACHE_LINE_MASK	(~(ARC_ICACHE_LINE_LEN - 1))
+#define DCACHE_LINE_MASK	(~(ARC_DCACHE_LINE_LEN - 1))
+
+#if ARC_ICACHE_LINE_LEN != ARC_DCACHE_LINE_LEN
+#error "Need to fix some code as I/D cache lines not same"
+#else
+#define is_not_cache_aligned(p)	((unsigned long)p & (~DCACHE_LINE_MASK))
+#endif
+
+#ifndef __ASSEMBLY__
+
+/* Uncached access macros */
+#define arc_read_uncached_32(ptr)	\
+({					\
+	unsigned int __ret;		\
+	__asm__ __volatile__(		\
+	"	ld.di %0, [%1]	\n"	\
+	: "=r"(__ret)			\
+	: "r"(ptr));			\
+	__ret;				\
+})
+
+#define arc_write_uncached_32(ptr, data)\
+({					\
+	__asm__ __volatile__(		\
+	"	st.di %0, [%1]	\n"	\
+	:				\
+	: "r"(data), "r"(ptr));		\
+})
+
+/* used to give SHMLBA a value to avoid Cache Aliasing */
+extern unsigned int ARC_shmlba;
+
+#define ARCH_DMA_MINALIGN      L1_CACHE_BYTES
+
+/*
+ * ARC700 doesn't cache any access in top 256M.
+ * Ideal for wiring memory mapped peripherals as we don't need to do
+ * explicit uncached accesses (LD.di/ST.di) hence more portable drivers
+ */
+#define ARC_UNCACHED_ADDR_SPACE	0xc0000000
+
+extern void arc_cache_init(void);
+extern char *arc_cache_mumbojumbo(int cpu_id, char *buf, int len);
+extern void __init read_decode_cache_bcr(void);
+#endif
+
 #endif /* _ASM_CACHE_H */

arch/arc/include/asm/cachectl.h

+/*
+ * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __ARC_ASM_CACHECTL_H
+#define __ARC_ASM_CACHECTL_H
+
+/*
+ * ARC ABI flags defined for Android's finegrained cacheflush requirements
+ */
+#define CF_I_INV	0x0002
+#define CF_D_FLUSH	0x0010
+#define CF_D_FLUSH_INV	0x0020
+
+#define CF_DEFAULT	(CF_I_INV | CF_D_FLUSH)
+
+/*
+ * Standard flags expected by cacheflush system call users
+ */
+#define ICACHE	CF_I_INV
+#define DCACHE	CF_D_FLUSH
+#define BCACHE	(CF_I_INV | CF_D_FLUSH)
+
+#endif

arch/arc/include/asm/cacheflush.h

+/*
+ * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ *  vineetg: May 2011: for Non-aliasing VIPT D-cache following can be NOPs
+ *   -flush_cache_dup_mm (fork)
+ *   -likewise for flush_cache_mm (exit/execve)
+ *   -likewise for flush_cache_{range,page} (munmap, exit, COW-break)
+ *
+ *  vineetg: April 2008
+ *   -Added a critical CacheLine flush to copy_to_user_page( ) which
+ *     was causing gdbserver to not setup breakpoints consistently
+ */
+
+#ifndef _ASM_CACHEFLUSH_H
+#define _ASM_CACHEFLUSH_H
+
+#include <linux/mm.h>
+
+void flush_cache_all(void);
+
+void flush_icache_range(unsigned long start, unsigned long end);
+void flush_icache_page(struct vm_area_struct *vma, struct page *page);
+void flush_icache_range_vaddr(unsigned long paddr, unsigned long u_vaddr,
+				     int len);
+
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
+
+void flush_dcache_page(struct page *page);
+
+void dma_cache_wback_inv(unsigned long start, unsigned long sz);
+void dma_cache_inv(unsigned long start, unsigned long sz);
+void dma_cache_wback(unsigned long start, unsigned long sz);
+
+#define flush_dcache_mmap_lock(mapping)		do { } while (0)
+#define flush_dcache_mmap_unlock(mapping)	do { } while (0)
+
+/* TBD: optimize this */
+#define flush_cache_vmap(start, end)		flush_cache_all()
+#define flush_cache_vunmap(start, end)		flush_cache_all()
+
+/*
+ * VM callbacks when entire/range of user-space V-P mappings are
+ * torn-down/get-invalidated
+ *
+ * Currently we don't support D$ aliasing configs for our VIPT caches
+ * NOPS for VIPT Cache with non-aliasing D$ configurations only
+ */
+#define flush_cache_dup_mm(mm)			/* called on fork */
+#define flush_cache_mm(mm)			/* called on munmap/exit */
+#define flush_cache_range(mm, u_vstart, u_vend)
+#define flush_cache_page(vma, u_vaddr, pfn)	/* PF handling/COW-break */
+
+#define copy_to_user_page(vma, page, vaddr, dst, src, len)		\
+do {									\
+	memcpy(dst, src, len);						\
+	if (vma->vm_flags & VM_EXEC)					\
+		flush_icache_range_vaddr((unsigned long)(dst), vaddr, len);\
+} while (0)
+
+#define copy_from_user_page(vma, page, vaddr, dst, src, len)		\
+	memcpy(dst, src, len);						\
+
+#endif