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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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ea31a6b203
On many of the newer MIPS32 cores, CP0 CONFIG2 bit 12 (L2B) indicates that the L2 cache is disabled and therefore Linux should not attempt to use it. [Ralf: Moved the code added by Kevin's original patch into a separate function that can easily be replaced for platforms that need more a different probe.] Signed-off-by: Kevin Cernekee <cernekee@gmail.com> Cc: linux-mips@linux-mips.org> Cc: <linux-kernel@vger.kernel.org> Patchwork: https://patchwork.linux-mips.org/patch/1723/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
143 lines
3.2 KiB
C
143 lines
3.2 KiB
C
/*
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* Copyright (C) 2006 Chris Dearman (chris@mips.com),
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*/
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <asm/mipsregs.h>
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#include <asm/bcache.h>
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#include <asm/cacheops.h>
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#include <asm/page.h>
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#include <asm/pgtable.h>
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#include <asm/system.h>
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#include <asm/mmu_context.h>
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#include <asm/r4kcache.h>
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/*
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* MIPS32/MIPS64 L2 cache handling
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*/
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/*
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* Writeback and invalidate the secondary cache before DMA.
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*/
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static void mips_sc_wback_inv(unsigned long addr, unsigned long size)
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{
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blast_scache_range(addr, addr + size);
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}
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/*
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* Invalidate the secondary cache before DMA.
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*/
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static void mips_sc_inv(unsigned long addr, unsigned long size)
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{
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unsigned long lsize = cpu_scache_line_size();
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unsigned long almask = ~(lsize - 1);
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cache_op(Hit_Writeback_Inv_SD, addr & almask);
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cache_op(Hit_Writeback_Inv_SD, (addr + size - 1) & almask);
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blast_inv_scache_range(addr, addr + size);
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}
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static void mips_sc_enable(void)
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{
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/* L2 cache is permanently enabled */
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}
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static void mips_sc_disable(void)
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{
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/* L2 cache is permanently enabled */
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}
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static struct bcache_ops mips_sc_ops = {
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.bc_enable = mips_sc_enable,
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.bc_disable = mips_sc_disable,
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.bc_wback_inv = mips_sc_wback_inv,
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.bc_inv = mips_sc_inv
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};
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/*
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* Check if the L2 cache controller is activated on a particular platform.
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* MTI's L2 controller and the L2 cache controller of Broadcom's BMIPS
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* cores both use c0_config2's bit 12 as "L2 Bypass" bit, that is the
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* cache being disabled. However there is no guarantee for this to be
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* true on all platforms. In an act of stupidity the spec defined bits
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* 12..15 as implementation defined so below function will eventually have
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* to be replaced by a platform specific probe.
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*/
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static inline int mips_sc_is_activated(struct cpuinfo_mips *c)
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{
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/* Check the bypass bit (L2B) */
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switch (c->cputype) {
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case CPU_34K:
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case CPU_74K:
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case CPU_1004K:
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case CPU_BMIPS5000:
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if (config2 & (1 << 12))
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return 0;
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}
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tmp = (config2 >> 4) & 0x0f;
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if (0 < tmp && tmp <= 7)
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c->scache.linesz = 2 << tmp;
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else
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return 0;
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}
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static inline int __init mips_sc_probe(void)
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{
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struct cpuinfo_mips *c = ¤t_cpu_data;
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unsigned int config1, config2;
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unsigned int tmp;
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/* Mark as not present until probe completed */
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c->scache.flags |= MIPS_CACHE_NOT_PRESENT;
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/* Ignore anything but MIPSxx processors */
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if (c->isa_level != MIPS_CPU_ISA_M32R1 &&
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c->isa_level != MIPS_CPU_ISA_M32R2 &&
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c->isa_level != MIPS_CPU_ISA_M64R1 &&
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c->isa_level != MIPS_CPU_ISA_M64R2)
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return 0;
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/* Does this MIPS32/MIPS64 CPU have a config2 register? */
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config1 = read_c0_config1();
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if (!(config1 & MIPS_CONF_M))
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return 0;
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config2 = read_c0_config2();
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if (!mips_sc_is_activated(c))
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return 0;
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tmp = (config2 >> 8) & 0x0f;
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if (0 <= tmp && tmp <= 7)
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c->scache.sets = 64 << tmp;
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else
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return 0;
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tmp = (config2 >> 0) & 0x0f;
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if (0 <= tmp && tmp <= 7)
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c->scache.ways = tmp + 1;
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else
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return 0;
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c->scache.waysize = c->scache.sets * c->scache.linesz;
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c->scache.waybit = __ffs(c->scache.waysize);
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c->scache.flags &= ~MIPS_CACHE_NOT_PRESENT;
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return 1;
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}
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int __cpuinit mips_sc_init(void)
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{
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int found = mips_sc_probe();
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if (found) {
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mips_sc_enable();
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bcops = &mips_sc_ops;
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}
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return found;
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}
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