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author | Neil Armstrong <narmstrong@baylibre.com> | 2016-09-09 12:23:11 +0200 |
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committer | Neil Armstrong <narmstrong@baylibre.com> | 2016-11-23 09:53:54 +0100 |
commit | af76e806b5b72da66b7c37d792ec422bafa14c22 (patch) | |
tree | 4c4e8d10a0a0c5c71ff20672fb90b597899ba5d5 /arch/arm/mach-oxnas | |
parent | 1001354ca34179f3db924eb66672442a173147dc (diff) | |
download | op-kernel-dev-af76e806b5b72da66b7c37d792ec422bafa14c22.zip op-kernel-dev-af76e806b5b72da66b7c37d792ec422bafa14c22.tar.gz |
ARM: oxnas: Add OX820 SMP support
The Oxford Semiconductor OX820 is a ARM11MPcore based SoC sharing some
features with the OX810 earlier SoC.
This patch adds the core to wake up the second core.
Clarifications about Copyrights dates :
- hotplug.c was taken from an old versatile code by Ma Haijun and left verbatim
- headsmp.S was taken from an old versatile code and adapted by Ma Haijun
- platsmp.c is a mix from versatile code, Ma Haijun code and my code for DT
Hence the 2002/2003 ARM Coryrights and 2013 Ma Haijun Copyrights.
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Diffstat (limited to 'arch/arm/mach-oxnas')
-rw-r--r-- | arch/arm/mach-oxnas/Makefile | 2 | ||||
-rw-r--r-- | arch/arm/mach-oxnas/headsmp.S | 26 | ||||
-rw-r--r-- | arch/arm/mach-oxnas/hotplug.c | 109 | ||||
-rw-r--r-- | arch/arm/mach-oxnas/platsmp.c | 102 |
4 files changed, 239 insertions, 0 deletions
diff --git a/arch/arm/mach-oxnas/Makefile b/arch/arm/mach-oxnas/Makefile new file mode 100644 index 0000000..b625906 --- /dev/null +++ b/arch/arm/mach-oxnas/Makefile @@ -0,0 +1,2 @@ +obj-$(CONFIG_SMP) += platsmp.o headsmp.o +obj-$(CONFIG_HOTPLUG_CPU) += hotplug.o diff --git a/arch/arm/mach-oxnas/headsmp.S b/arch/arm/mach-oxnas/headsmp.S new file mode 100644 index 0000000..25fd4f8 --- /dev/null +++ b/arch/arm/mach-oxnas/headsmp.S @@ -0,0 +1,26 @@ +/* + * Copyright (C) 2013 Ma Haijun <mahaijuns@gmail.com> + * Copyright (c) 2003 ARM Limited + * 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/linkage.h> +#include <linux/init.h> + + __INIT + +/* + * OX820 specific entry point for secondary CPUs. + */ +ENTRY(ox820_secondary_startup) + mov r4, #0 + /* invalidate both caches and branch target cache */ + mcr p15, 0, r4, c7, c7, 0 + /* + * we've been released from the holding pen: secondary_stack + * should now contain the SVC stack for this core + */ + b secondary_startup diff --git a/arch/arm/mach-oxnas/hotplug.c b/arch/arm/mach-oxnas/hotplug.c new file mode 100644 index 0000000..854f29b --- /dev/null +++ b/arch/arm/mach-oxnas/hotplug.c @@ -0,0 +1,109 @@ +/* + * 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 <asm/cp15.h> +#include <asm/smp_plat.h> + +static inline void cpu_enter_lowpower(void) +{ + unsigned int v; + + 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"); +} + +static inline void platform_do_lowpower(unsigned int cpu, int *spurious) +{ + /* + * 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 + */ + for (;;) { + /* + * here's the WFI + */ + asm(".word 0xe320f003\n" + : + : + : "memory", "cc"); + + if (pen_release == cpu_logical_map(cpu)) { + /* + * OK, proper wakeup, we're done + */ + 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)++; + } +} + +/* + * platform-specific code to shutdown a CPU + * + * Called with IRQs disabled + */ +void ox820_cpu_die(unsigned int cpu) +{ + int spurious = 0; + + /* + * 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); +} diff --git a/arch/arm/mach-oxnas/platsmp.c b/arch/arm/mach-oxnas/platsmp.c new file mode 100644 index 0000000..442cc8a --- /dev/null +++ b/arch/arm/mach-oxnas/platsmp.c @@ -0,0 +1,102 @@ +/* + * Copyright (C) 2016 Neil Armstrong <narmstrong@baylibre.com> + * Copyright (C) 2013 Ma Haijun <mahaijuns@gmail.com> + * 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/io.h> +#include <linux/delay.h> +#include <linux/of.h> +#include <linux/of_address.h> + +#include <asm/cacheflush.h> +#include <asm/cp15.h> +#include <asm/smp_plat.h> +#include <asm/smp_scu.h> + +extern void ox820_secondary_startup(void); +extern void ox820_cpu_die(unsigned int cpu); + +static void __iomem *cpu_ctrl; +static void __iomem *gic_cpu_ctrl; + +#define HOLDINGPEN_CPU_OFFSET 0xc8 +#define HOLDINGPEN_LOCATION_OFFSET 0xc4 + +#define GIC_NCPU_OFFSET(cpu) (0x100 + (cpu)*0x100) +#define GIC_CPU_CTRL 0x00 +#define GIC_CPU_CTRL_ENABLE 1 + +int __init ox820_boot_secondary(unsigned int cpu, struct task_struct *idle) +{ + /* + * Write the address of secondary startup into the + * system-wide flags register. The BootMonitor waits + * until it receives a soft interrupt, and then the + * secondary CPU branches to this address. + */ + writel(virt_to_phys(ox820_secondary_startup), + cpu_ctrl + HOLDINGPEN_LOCATION_OFFSET); + + writel(cpu, cpu_ctrl + HOLDINGPEN_CPU_OFFSET); + + /* + * Enable GIC cpu interface in CPU Interface Control Register + */ + writel(GIC_CPU_CTRL_ENABLE, + gic_cpu_ctrl + GIC_NCPU_OFFSET(cpu) + GIC_CPU_CTRL); + + /* + * Send the secondary CPU a soft interrupt, thereby causing + * the boot monitor to read the system wide flags register, + * and branch to the address found there. + */ + arch_send_wakeup_ipi_mask(cpumask_of(cpu)); + + return 0; +} + +static void __init ox820_smp_prepare_cpus(unsigned int max_cpus) +{ + struct device_node *np; + void __iomem *scu_base; + + np = of_find_compatible_node(NULL, NULL, "arm,arm11mp-scu"); + scu_base = of_iomap(np, 0); + of_node_put(np); + if (!scu_base) + return; + + /* Remap CPU Interrupt Interface Registers */ + np = of_find_compatible_node(NULL, NULL, "arm,arm11mp-gic"); + gic_cpu_ctrl = of_iomap(np, 1); + of_node_put(np); + if (!gic_cpu_ctrl) + goto unmap_scu; + + np = of_find_compatible_node(NULL, NULL, "oxsemi,ox820-sys-ctrl"); + cpu_ctrl = of_iomap(np, 0); + of_node_put(np); + if (!cpu_ctrl) + goto unmap_scu; + + scu_enable(scu_base); + flush_cache_all(); + +unmap_scu: + iounmap(scu_base); +} + +static const struct smp_operations ox820_smp_ops __initconst = { + .smp_prepare_cpus = ox820_smp_prepare_cpus, + .smp_boot_secondary = ox820_boot_secondary, +#ifdef CONFIG_HOTPLUG_CPU + .cpu_die = ox820_cpu_die, +#endif +}; + +CPU_METHOD_OF_DECLARE(ox820_smp, "oxsemi,ox820-smp", &ox820_smp_ops); |