From mboxrd@z Thu Jan 1 00:00:00 1970 From: gregory.clement@free-electrons.com (Gregory CLEMENT) Date: Fri, 27 Jun 2014 00:43:25 +0200 Subject: [PATCH 2/5] ARM: smp_scu: Add the enable speculative linefills operation In-Reply-To: <1403822608-31158-1-git-send-email-gregory.clement@free-electrons.com> References: <1403822608-31158-1-git-send-email-gregory.clement@free-electrons.com> Message-ID: <1403822608-31158-3-git-send-email-gregory.clement@free-electrons.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Quotin the ARM datasheet "When set, coherent linefill requests are sent speculatively to the L2C-310 in parallel with the tag look-up. If the tag look-up misses, the confirmed linefill is sent to the L2C-310 and gets RDATA earlier because the data request was already initiated by the speculative request. " Some SoC (such as the Armada 375/38x) can benefit of this feature. As this is something related to the Cortex A9 and not specific to a SoC, we can expose it in a common place. Signed-off-by: Gregory CLEMENT --- arch/arm/include/asm/smp_scu.h | 3 +++ arch/arm/kernel/smp_scu.c | 22 ++++++++++++++++++++++ 2 files changed, 25 insertions(+) diff --git a/arch/arm/include/asm/smp_scu.h b/arch/arm/include/asm/smp_scu.h index 0393fbab8dd5..d9650dce48c7 100644 --- a/arch/arm/include/asm/smp_scu.h +++ b/arch/arm/include/asm/smp_scu.h @@ -26,6 +26,7 @@ static inline unsigned long scu_a9_get_base(void) #ifdef CONFIG_HAVE_ARM_SCU unsigned int scu_get_core_count(void __iomem *); int scu_power_mode(void __iomem *, unsigned int); +void scu_spec_linefills_enable(void __iomem *scu_base, bool enable); #else static inline unsigned int scu_get_core_count(void __iomem *scu_base) { @@ -35,6 +36,8 @@ static inline int scu_power_mode(void __iomem *scu_base, unsigned int mode) { return -EINVAL; } +static inline void scu_spec_linefills_enable(void __iomem *scu_base, + bool enable) {} #endif #if defined(CONFIG_SMP) && defined(CONFIG_HAVE_ARM_SCU) diff --git a/arch/arm/kernel/smp_scu.c b/arch/arm/kernel/smp_scu.c index cfea41b41ad0..3fd21a495028 100644 --- a/arch/arm/kernel/smp_scu.c +++ b/arch/arm/kernel/smp_scu.c @@ -18,6 +18,7 @@ #define SCU_CTRL 0x00 #define SCU_CTRL_ENABLE BIT(1) +#define SCU_CTRL_SPEC_LINEFILLS BIT(3) #define SCU_CONFIG 0x04 #define SCU_CPU_STATUS 0x08 #define SCU_INVALIDATE 0x0c @@ -88,3 +89,24 @@ int scu_power_mode(void __iomem *scu_base, unsigned int mode) return 0; } + +/* + * When enabled, coherent linefill requests are sent speculatively to + * the L2C-310 in parallel with the tag look-up + * + */ +void scu_spec_linefills_enable(void __iomem *scu_base, bool enable) +{ + u32 scu_ctrl; + + scu_ctrl = readl_relaxed(scu_base + SCU_CTRL); + /* already enabled? */ + if (scu_ctrl & SCU_CTRL_ENABLE) + return; + if (enable) + scu_ctrl |= SCU_CTRL_SPEC_LINEFILLS; + else + scu_ctrl &= ~SCU_CTRL_SPEC_LINEFILLS; + + writel_relaxed(scu_ctrl, scu_base + SCU_CTRL); +} -- 1.8.1.2