From mboxrd@z Thu Jan 1 00:00:00 1970 From: magnus.damm@gmail.com (Magnus Damm) Date: Thu, 30 May 2013 17:52:20 +0900 Subject: [PATCH 03/05] ARM: shmobile: r8a73a4 CA15 setup WFE as NOP In-Reply-To: <20130530085152.24374.64208.sendpatchset@w520> References: <20130530085152.24374.64208.sendpatchset@w520> Message-ID: <20130530085220.24374.94574.sendpatchset@w520> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org From: Magnus Damm Configure CA15 included in r8a73a4 to treat WFE as NOP. This works around hardware issue found in APE6, needed for CA7 cluster to work together with CA15 cluster. Not-yet-Signed-off-by: Magnus Damm --- arch/arm/mach-shmobile/smp-r8a73a4.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) --- 0006/arch/arm/mach-shmobile/smp-r8a73a4.c +++ work/arch/arm/mach-shmobile/smp-r8a73a4.c 2013-05-22 14:16:59.000000000 +0900 @@ -45,6 +45,20 @@ #define CCI_SNOOP 0x0000 #define CCI_STATUS 0x000c +static inline void r8a73a4_execute_wfe_as_nop(void) +{ + unsigned int v; + + /* set bit 7 in ACTLR */ + asm volatile( + " mrc p15, 0, %0, c1, c0, 1\n" + " orr %0, %0, #0x40\n" + " mcr p15, 0, %0, c1, c0, 1\n" + : "=&r" (v) + : + : "cc"); +} + static void __init r8a73a4_smp_prepare_cpus(unsigned int max_cpus) { u32 bar; @@ -71,6 +85,8 @@ static void __init r8a73a4_smp_prepare_c while (__raw_readl(p + CCI_STATUS)) /* wait for pending bit low */; iounmap(p); + + r8a73a4_execute_wfe_as_nop(); } static int __cpuinit r8a73a4_boot_secondary(unsigned int cpu, struct task_struct *idle) @@ -85,6 +101,13 @@ static int __cpuinit r8a73a4_boot_second return 0; } +static void __cpuinit r8a73a4_secondary_init(unsigned int cpu) +{ + /* CA15 need SW workaround */ + if (cpu_logical_map(cpu) < 4) + r8a73a4_execute_wfe_as_nop(); +} + #ifdef CONFIG_HOTPLUG_CPU static int r8a73a4_cpu_kill(unsigned int cpu) { @@ -169,6 +192,7 @@ static int r8a73a4_cpu_disable(unsigned struct smp_operations r8a73a4_smp_ops __initdata = { .smp_prepare_cpus = r8a73a4_smp_prepare_cpus, .smp_boot_secondary = r8a73a4_boot_secondary, + .smp_secondary_init = r8a73a4_secondary_init, #ifdef CONFIG_HOTPLUG_CPU .cpu_kill = r8a73a4_cpu_kill, .cpu_die = r8a73a4_cpu_die,