[PATCH 2/2] nds32: support hardware prefetcher

[Nylon Chen]

We add a config for user to enable or disable this feature.
It can be used to control the hardware prefetch function.

Signed-off-by: Nylon Chen <nylon7@xxxxxxxxxxxxx>
---
 arch/nds32/Kconfig.cpu            | 7 +++++++
 arch/nds32/include/asm/bitfield.h | 6 ++++++
 arch/nds32/kernel/head.S          | 2 +-
 arch/nds32/kernel/setup.c         | 7 +++++++
 4 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/arch/nds32/Kconfig.cpu b/arch/nds32/Kconfig.cpu
index b8c8984d1456..8fd1236db3fa 100644
--- a/arch/nds32/Kconfig.cpu
+++ b/arch/nds32/Kconfig.cpu
@@ -143,6 +143,13 @@ config CACHE_L2
 	  Say Y here to enable L2 cache if your SoC are integrated with L2CC.
 	  If unsure, say N.
 
+config HW_PRE
+	bool "Enable hardware prefetcher"
+        default y
+	help
+	  Say Y here to enable hardware prefetcher feature.
+	  Only when CPU_VER.REV >= 0x09 can support.
+
 menu "Memory configuration"
 
 choice
diff --git a/arch/nds32/include/asm/bitfield.h b/arch/nds32/include/asm/bitfield.h
index 8e84fc385b94..2a33700e7ffa 100644
--- a/arch/nds32/include/asm/bitfield.h
+++ b/arch/nds32/include/asm/bitfield.h
@@ -735,14 +735,20 @@
 #define N13MISC_CTL_offRTP	1	/* Disable Return Target Predictor */
 #define N13MISC_CTL_offPTEPF	2	/* Disable HPTWK L2 PTE pefetch */
 #define N13MISC_CTL_offSP_SHADOW_EN	4	/* Enable shadow stack pointers */
+#define MISC_CTL_offHWPRE      11      /* Enable HardWare PREFETCH */
 /* bit 6, 9:31 reserved */
 
 #define N13MISC_CTL_makBTB	( 0x1  << N13MISC_CTL_offBTB )
 #define N13MISC_CTL_makRTP	( 0x1  << N13MISC_CTL_offRTP )
 #define N13MISC_CTL_makPTEPF	( 0x1  << N13MISC_CTL_offPTEPF )
 #define N13MISC_CTL_makSP_SHADOW_EN	( 0x1  << N13MISC_CTL_offSP_SHADOW_EN )
+#define MISC_CTL_makHWPRE_EN     ( 0x1  << MISC_CTL_offHWPRE )
 
+#ifdef CONFIG_HW_PRE
+#define MISC_init	(N13MISC_CTL_makBTB|N13MISC_CTL_makRTP|N13MISC_CTL_makSP_SHADOW_EN|MISC_CTL_makHWPRE_EN)
+#else
 #define MISC_init	(N13MISC_CTL_makBTB|N13MISC_CTL_makRTP|N13MISC_CTL_makSP_SHADOW_EN)
+#endif
 
 /******************************************************************************
  * PRUSR_ACC_CTL (Privileged Resource User Access Control Registers)
diff --git a/arch/nds32/kernel/head.S b/arch/nds32/kernel/head.S
index c5fdae174ced..029e27fb0d71 100644
--- a/arch/nds32/kernel/head.S
+++ b/arch/nds32/kernel/head.S
@@ -160,7 +160,7 @@ _tlb:
 #endif
 	mtsr    $r3, $TLB_MISC
 
-	mfsr    $r0, $MISC_CTL      ! Enable BTB and RTP and shadow sp
+	mfsr    $r0, $MISC_CTL      ! Enable BTB, RTP, shadow sp and HW_PRE
 	ori     $r0, $r0, #MISC_init
 	mtsr    $r0, $MISC_CTL
 
diff --git a/arch/nds32/kernel/setup.c b/arch/nds32/kernel/setup.c
index e39274a21481..39384952d2ef 100644
--- a/arch/nds32/kernel/setup.c
+++ b/arch/nds32/kernel/setup.c
@@ -38,6 +38,7 @@
 #define HWCAP_FPU_DP		0x040000
 #define HWCAP_V2		0x080000
 #define HWCAP_DX_REGS		0x100000
+#define HWCAP_HWPRE		0x200000
 
 unsigned long cpu_id, cpu_rev, cpu_cfgid;
 char cpu_series;
@@ -73,6 +74,7 @@ static const char *hwcap_str[] = {
 	"dx_regs",
 	"fpu_dp",
 	"v2",
+	"hw_pre",
 	NULL,
 };
 
@@ -213,6 +215,11 @@ static void __init setup_cpuinfo(void)
 	if (__nds32__mfsr(NDS32_SR_MSC_CFG) & MSC_CFG_mskL2C)
 		elf_hwcap |= HWCAP_L2C;
 
+#ifdef CONFIG_HW_PRE
+	if (__nds32__mfsr(NDS32_SR_MISC_CTL) & MISC_CTL_makHWPRE_EN)
+		elf_hwcap |= HWCAP_HWPRE;
+#endif
+
 	tmp = __nds32__mfsr(NDS32_SR_CACHE_CTL);
 	if (!IS_ENABLED(CONFIG_CPU_DCACHE_DISABLE))
 		tmp |= CACHE_CTL_mskDC_EN;
-- 
2.18.0