Commit d1f317d8 authored by Vineet Gupta's avatar Vineet Gupta
Browse files

ARCv2: MMUv4: cache programming model changes 



Caveats about cache flush on ARCv2 based cores

- dcache is PIPT so paddr is sufficient for cache maintenance ops (no
  need to setup PTAG reg

- icache is still VIPT but only aliasing configs need PTAG setup

So basically this is departure from MMU-v3 which always need vaddr in
line ops registers (DC_IVDL, DC_FLDL, IC_IVIL) but paddr in DC_PTAG,
IC_PTAG respectively.

Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
parent d7a512bf

arch/arc/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -223,7 +223,7 @@ config ARC_CACHE_PAGES 


config ARC_CACHE_VIPT_ALIASING

	bool "Support VIPT Aliasing D$"

	depends on ARC_HAS_DCACHE

	depends on ARC_HAS_DCACHE && ISA_ARCOMPACT

	default n



endif	#ARC_CACHE

arch/arc/include/asm/arcregs.h

+3 −2
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#define ARC_REG_FP_BCR		0x6B	/* ARCompact: Single-Precision FPU */

#define ARC_REG_DPFP_BCR	0x6C	/* ARCompact: Dbl Precision FPU */

#define ARC_REG_FP_V2_BCR	0xc8	/* ARCv2 FPU */

#define ARC_REG_SLC_BCR		0xce

#define ARC_REG_DCCM_BCR	0x74	/* DCCM Present + SZ */

#define ARC_REG_TIMERS_BCR	0x75

#define ARC_REG_AP_BCR		0x76
@@ -331,7 +332,7 @@ struct cpuinfo_arc_mmu { 
};



struct cpuinfo_arc_cache {

	unsigned int sz_k:8, line_len:8, assoc:4, ver:4, alias:1, vipt:1, pad:6;

	unsigned int sz_k:14, line_len:8, assoc:4, ver:4, alias:1, vipt:1;

};



struct cpuinfo_arc_bpu {
@@ -343,7 +344,7 @@ struct cpuinfo_arc_ccm { 
};



struct cpuinfo_arc {

	struct cpuinfo_arc_cache icache, dcache;

	struct cpuinfo_arc_cache icache, dcache, slc;

	struct cpuinfo_arc_mmu mmu;

	struct cpuinfo_arc_bpu bpu;

	struct bcr_identity core;

arch/arc/include/asm/cache.h

+3 −0
Original line number Diff line number Diff line
@@ -82,4 +82,7 @@ extern void read_decode_cache_bcr(void); 
#define DC_CTRL_INV_MODE_FLUSH  0x40

#define DC_CTRL_FLUSH_STATUS    0x100



/*System-level cache (L2 cache) related Auxiliary registers */

#define ARC_REG_SLC_CFG		0x901



#endif /* _ASM_CACHE_H */

arch/arc/mm/cache.c

+97 −15
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ 
char *arc_cache_mumbojumbo(int c, char *buf, int len)

{

	int n = 0;

	struct cpuinfo_arc_cache *p;



#define PR_CACHE(p, cfg, str)						\

	if (!(p)->ver)							\
@@ -39,6 +40,11 @@ char *arc_cache_mumbojumbo(int c, char *buf, int len) 
	PR_CACHE(&cpuinfo_arc700[c].icache, CONFIG_ARC_HAS_ICACHE, "I-Cache");

	PR_CACHE(&cpuinfo_arc700[c].dcache, CONFIG_ARC_HAS_DCACHE, "D-Cache");



	p = &cpuinfo_arc700[c].slc;

	if (p->ver)

		n += scnprintf(buf + n, len - n,

			"SLC\t\t: %uK, %uB Line\n", p->sz_k, p->line_len);



	return buf;

}
@@ -49,7 +55,7 @@ char *arc_cache_mumbojumbo(int c, char *buf, int len) 
 */

void read_decode_cache_bcr(void)

{

	struct cpuinfo_arc_cache *p_ic, *p_dc;

	struct cpuinfo_arc_cache *p_ic, *p_dc, *p_slc;

	unsigned int cpu = smp_processor_id();

	struct bcr_cache {

#ifdef CONFIG_CPU_BIG_ENDIAN
@@ -59,14 +65,29 @@ void read_decode_cache_bcr(void) 
#endif

	} ibcr, dbcr;



	struct bcr_generic sbcr;



	struct bcr_slc_cfg {

#ifdef CONFIG_CPU_BIG_ENDIAN

		unsigned int pad:24, way:2, lsz:2, sz:4;

#else

		unsigned int sz:4, lsz:2, way:2, pad:24;

#endif

	} slc_cfg;



	p_ic = &cpuinfo_arc700[cpu].icache;

	READ_BCR(ARC_REG_IC_BCR, ibcr);



	if (!ibcr.ver)

		goto dc_chk;



	if (ibcr.ver <= 3) {

		BUG_ON(ibcr.config != 3);

		p_ic->assoc = 2;		/* Fixed to 2w set assoc */

	} else if (ibcr.ver >= 4) {

		p_ic->assoc = 1 << ibcr.config;	/* 1,2,4,8 */

	}



	p_ic->line_len = 8 << ibcr.line_len;

	p_ic->sz_k = 1 << (ibcr.sz - 1);

	p_ic->ver = ibcr.ver;
@@ -78,15 +99,32 @@ dc_chk: 
	READ_BCR(ARC_REG_DC_BCR, dbcr);



	if (!dbcr.ver)

		return;

		goto slc_chk;



	if (dbcr.ver <= 3) {

		BUG_ON(dbcr.config != 2);

		p_dc->assoc = 4;		/* Fixed to 4w set assoc */

		p_dc->vipt = 1;

		p_dc->alias = p_dc->sz_k/p_dc->assoc/TO_KB(PAGE_SIZE) > 1;

	} else if (dbcr.ver >= 4) {

		p_dc->assoc = 1 << dbcr.config;	/* 1,2,4,8 */

		p_dc->vipt = 0;

		p_dc->alias = 0;		/* PIPT so can't VIPT alias */

	}



	p_dc->line_len = 16 << dbcr.line_len;

	p_dc->sz_k = 1 << (dbcr.sz - 1);

	p_dc->ver = dbcr.ver;

	p_dc->vipt = 1;

	p_dc->alias = p_dc->sz_k/p_dc->assoc/TO_KB(PAGE_SIZE) > 1;



slc_chk:

	p_slc = &cpuinfo_arc700[cpu].slc;

	READ_BCR(ARC_REG_SLC_BCR, sbcr);

	if (sbcr.ver) {

		READ_BCR(ARC_REG_SLC_CFG, slc_cfg);

		p_slc->ver = sbcr.ver;

		p_slc->sz_k = 128 << slc_cfg.sz;

		p_slc->line_len = (slc_cfg.lsz == 0) ? 128 : 64;

	}

}



/*
@@ -225,10 +263,53 @@ void __cache_line_loop_v3(unsigned long paddr, unsigned long vaddr, 
	}

}



/*

 * In HS38x (MMU v4), although icache is VIPT, only paddr is needed for cache

 * maintenance ops (in IVIL reg), as long as icache doesn't alias.

 *

 * For Aliasing icache, vaddr is also needed (in IVIL), while paddr is

 * specified in PTAG (similar to MMU v3)

 */

static inline

void __cache_line_loop_v4(unsigned long paddr, unsigned long vaddr,

			  unsigned long sz, const int cacheop)

{

	unsigned int aux_cmd;

	int num_lines;

	const int full_page_op = __builtin_constant_p(sz) && sz == PAGE_SIZE;



	if (cacheop == OP_INV_IC) {

		aux_cmd = ARC_REG_IC_IVIL;

	} else {

		/* d$ cmd: INV (discard or wback-n-discard) OR FLUSH (wback) */

		aux_cmd = cacheop & OP_INV ? ARC_REG_DC_IVDL : ARC_REG_DC_FLDL;

	}



	/* Ensure we properly floor/ceil the non-line aligned/sized requests

	 * and have @paddr - aligned to cache line and integral @num_lines.

	 * This however can be avoided for page sized since:

	 *  -@paddr will be cache-line aligned already (being page aligned)

	 *  -@sz will be integral multiple of line size (being page sized).

	 */

	if (!full_page_op) {

		sz += paddr & ~CACHE_LINE_MASK;

		paddr &= CACHE_LINE_MASK;

	}



	num_lines = DIV_ROUND_UP(sz, L1_CACHE_BYTES);



	while (num_lines-- > 0) {

		write_aux_reg(aux_cmd, paddr);

		paddr += L1_CACHE_BYTES;

	}

}



#if (CONFIG_ARC_MMU_VER < 3)

#define __cache_line_loop	__cache_line_loop_v2

#elif (CONFIG_ARC_MMU_VER == 3)

#define __cache_line_loop	__cache_line_loop_v3

#elif (CONFIG_ARC_MMU_VER > 3)

#define __cache_line_loop	__cache_line_loop_v4

#endif



#ifdef CONFIG_ARC_HAS_DCACHE
@@ -669,7 +750,6 @@ void arc_cache_init(void) 


	if (IS_ENABLED(CONFIG_ARC_HAS_DCACHE)) {

		struct cpuinfo_arc_cache *dc = &cpuinfo_arc700[cpu].dcache;

		int handled;



		if (!dc->ver)

			panic("cache support enabled but non-existent cache\n");
@@ -678,8 +758,9 @@ void arc_cache_init(void) 
			panic("DCache line [%d] != kernel Config [%d]",

			      dc->line_len, L1_CACHE_BYTES);



		/* check for D-Cache aliasing */

		handled = IS_ENABLED(CONFIG_ARC_CACHE_VIPT_ALIASING);

		/* check for D-Cache aliasing on ARCompact: ARCv2 has PIPT */

		if (is_isa_arcompact()) {

			int handled = IS_ENABLED(CONFIG_ARC_CACHE_VIPT_ALIASING);



			if (dc->alias && !handled)

				panic("Enable CONFIG_ARC_CACHE_VIPT_ALIASING\n");
@@ -687,3 +768,4 @@ void arc_cache_init(void) 
				panic("Disable CONFIG_ARC_CACHE_VIPT_ALIASING\n");

		}

	}

}

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