diff options
Diffstat (limited to 'drivers/platform/sprd/hotplug.c')
| -rw-r--r-- | drivers/platform/sprd/hotplug.c | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/drivers/platform/sprd/hotplug.c b/drivers/platform/sprd/hotplug.c new file mode 100644 index 00000000..cf176183 --- /dev/null +++ b/drivers/platform/sprd/hotplug.c @@ -0,0 +1,167 @@ +/* linux arch/arm/mach-sc8830/hotplug.c + * + * Cloned from linux/arch/arm/mach-realview/hotplug.c + * + * Copyright (C) 2002 ARM Ltd. + * All Rights Reserved + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. +*/ +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/smp.h> +#include <linux/completion.h> +#include <linux/delay.h> +#include <linux/sched.h> +#include <linux/io.h> + +#include <soc/sprd/hardware.h> +#include <asm/cacheflush.h> +#include <asm/cp15.h> +#include <asm/smp_plat.h> +#include <soc/sprd/sci.h> +#include <soc/sprd/sci_glb_regs.h> + +extern volatile int pen_release; +#ifdef CONFIG_ARCH_SCX35 +int powerdown_cpus(int cpu); +int sci_shark_enter_lowpower(void); +#endif +static inline void cpu_enter_lowpower(void) +{ + unsigned int v; + + flush_cache_all(); + asm volatile( + " mcr p15, 0, %1, c7, c5, 0\n" + " mcr p15, 0, %1, c7, c10, 4\n" + /* + * Turn off coherency + */ + " mrc p15, 0, %0, c1, c0, 1\n" + " bic %0, %0, #0x20\n" + " mcr p15, 0, %0, c1, c0, 1\n" + " mrc p15, 0, %0, c1, c0, 0\n" + " bic %0, %0, %2\n" + " mcr p15, 0, %0, c1, c0, 0\n" + : "=&r" (v) + : "r" (0), "Ir" (CR_C) + : "cc"); +} + +static inline void cpu_leave_lowpower(void) +{ + unsigned int v; + + asm volatile( "mrc p15, 0, %0, c1, c0, 0\n" + " orr %0, %0, %1\n" + " mcr p15, 0, %0, c1, c0, 0\n" + " mrc p15, 0, %0, c1, c0, 1\n" + " orr %0, %0, #0x20\n" + " mcr p15, 0, %0, c1, c0, 1\n" + : "=&r" (v) + : "Ir" (CR_C) + : "cc"); +} + +extern unsigned int sprd_boot_magnum; + +static inline void platform_do_lowpower(unsigned int cpu, int *spurious) +{ + unsigned int val = sprd_boot_magnum; + + /* + * there is no power-control hardware on this platform, so all + * we can do is put the core into WFI; this is safe as the calling + * code will have already disabled interrupts + */ + + val |= (cpu_logical_map(cpu) & 0x0000000f); + for (;;) { + /* + * here's the WFI + */ + asm(".word 0xe320f003\n" + : + : + : "memory", "cc"); + + if (pen_release == val) { + /* + * OK, proper wakeup, we're done + */ + pr_info("platform_do_lowpower %x %x\n",pen_release,val); + break; + } + + /* + * Getting here, means that we have come out of WFI without + * having been woken up - this shouldn't happen + * + * Just note it happening - when we're woken, we can report + * its occurrence. + */ + (*spurious)++; + } +} + +int sprd_cpu_kill(unsigned int cpu) +{ +#ifdef CONFIG_ARCH_SCX35 + int i = 0; + printk("!! %d platform_cpu_kill %d !!\n", smp_processor_id(), cpu); + while (i < 20) { + //check wfi? + if (sci_glb_read(REG_AP_AHB_CA7_STANDBY_STATUS, -1UL) & (1 << cpu_logical_map(cpu))) + { + powerdown_cpus(cpu); + break; + } + udelay(100); + i++; + } + printk("platform_cpu_kill finished i=%d !!\n", i); + return (i >= 20? 0 : 1); +#endif + return 1; +} + +/* + * platform-specific code to shutdown a CPU + * + * Called with IRQs disabled + */ +void __cpuinit sprd_cpu_die(unsigned int cpu) +{ + int spurious = 0; + +#ifdef CONFIG_ARCH_SCX35 + sci_shark_enter_lowpower(); + panic("shouldn't be here \n"); +#endif + /* + * we're ready for shutdown now, so do it + */ + cpu_enter_lowpower(); + platform_do_lowpower(cpu, &spurious); + + /* + * bring this CPU back into the world of cache + * coherency, and then restore interrupts + */ + cpu_leave_lowpower(); + + if (spurious) + pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious); +} + +int sprd_cpu_disable(unsigned int cpu) +{ + /* + * we don't allow CPU 0 to be shutdown (it is still too special + * e.g. clock tick interrupts) + */ + return cpu == 0 ? -EPERM : 0; +} |