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powerpc/dt_cpu_ftrs: Add MMA feature

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Matrix multiple assist (MMA) is a new feature added to ISAv3.1 and
POWER10. Support on powernv can be selected via a firmware CPU device
tree feature which enables it via a PCR bit.

Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200521014341.29095-7-alistair@popple.id.au
This commit is contained in:
Alistair Popple 2020-05-21 11:43:40 +10:00 committed by Michael Ellerman
parent c63d688c3d
commit 87939d50e5
2 changed files with 18 additions and 2 deletions
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3
arch/powerpc/include/asm/reg.h
View file

@ -481,7 +481,8 @@
#define PCR_VEC_DIS (__MASK(63-0)) /* Vec. disable (bit NA since POWER8) */
#define PCR_VSX_DIS (__MASK(63-1)) /* VSX disable (bit NA since POWER8) */
#define PCR_TM_DIS (__MASK(63-2)) /* Trans. memory disable (POWER8) */
#define PCR_HIGH_BITS (PCR_VEC_DIS | PCR_VSX_DIS | PCR_TM_DIS)
#define PCR_MMA_DIS (__MASK(63-3)) /* Matrix-Multiply Accelerator */
#define PCR_HIGH_BITS (PCR_MMA_DIS | PCR_VEC_DIS | PCR_VSX_DIS | PCR_TM_DIS)
/*
* These bits are used in the function kvmppc_set_arch_compat() to specify and
* determine both the compatibility level which we want to emulate and the

17
arch/powerpc/kernel/dt_cpu_ftrs.c
View file

@ -75,6 +75,7 @@ static struct {
u64 lpcr_clear;
u64 hfscr;
u64 fscr;
u64 pcr;
} system_registers;
static void (*init_pmu_registers)(void);
@ -102,7 +103,7 @@ static void __restore_cpu_cpufeatures(void)
if (hv_mode) {
mtspr(SPRN_LPID, 0);
mtspr(SPRN_HFSCR, system_registers.hfscr);
mtspr(SPRN_PCR, PCR_MASK);
mtspr(SPRN_PCR, system_registers.pcr);
}
mtspr(SPRN_FSCR, system_registers.fscr);
@ -561,6 +562,18 @@ static int __init feat_enable_large_ci(struct dt_cpu_feature *f)
return 1;
}
static int __init feat_enable_mma(struct dt_cpu_feature *f)
{
u64 pcr;
feat_enable(f);
pcr = mfspr(SPRN_PCR);
pcr &= ~PCR_MMA_DIS;
mtspr(SPRN_PCR, pcr);
return 1;
}
struct dt_cpu_feature_match {
const char *name;
int (*enable)(struct dt_cpu_feature *f);
@ -635,6 +648,7 @@ static struct dt_cpu_feature_match __initdata
{"vector-binary16", feat_enable, 0},
{"wait-v3", feat_enable, 0},
{"prefix-instructions", feat_enable, 0},
{"matrix-multiply-assist", feat_enable_mma, 0},
};
static bool __initdata using_dt_cpu_ftrs;
@ -785,6 +799,7 @@ static void __init cpufeatures_setup_finished(void)
system_registers.lpcr = mfspr(SPRN_LPCR);
system_registers.hfscr = mfspr(SPRN_HFSCR);
system_registers.fscr = mfspr(SPRN_FSCR);
system_registers.pcr = mfspr(SPRN_PCR);
pr_info("final cpu/mmu features = 0x%016lx 0x%08x\n",
cur_cpu_spec->cpu_features, cur_cpu_spec->mmu_features);