On 10/15/2015 06:10 PM, Kapil Hali wrote: > > > On 10/15/2015 3:56 AM, Hauke Mehrtens wrote: >> On 10/14/2015 07:47 PM, Kapil Hali wrote: >>> Add SMP support for Broadcom's Northstar Plus SoC, >>> cpu enable method and pen_release procedures. This >>> changes also consolidates iProc family's - BCM NSP >>> and BCM Kona, SMP handling in a common file. >> >> This will probably also work on normal Northstar CPUs without changes. >> > I think, it should work for most of the variants of Northstar family, > except for those which have a BOOTROM bug. Which SoC are affected by this BOOTROM bug? >>> Northstar Plus SoC is based on ARM Cortex-A9 >>> revision r3p0 which requires configuration for ARM >>> Errata 764369 for SMP. This change adds the needed >>> configuration option. >>> >>> Signed-off-by: Kapil Hali <kapilh@xxxxxxxxxxxx> >>> --- >>> arch/arm/mach-bcm/Kconfig | 2 + >>> arch/arm/mach-bcm/Makefile | 8 +- >>> arch/arm/mach-bcm/bcm_nsp.h | 19 ++++ >>> arch/arm/mach-bcm/headsmp.S | 37 ++++++++ >>> arch/arm/mach-bcm/{kona_smp.c => platsmp.c} | 142 ++++++++++++++++++++++++++-- >>> 5 files changed, 197 insertions(+), 11 deletions(-) >>> create mode 100644 arch/arm/mach-bcm/bcm_nsp.h >>> create mode 100644 arch/arm/mach-bcm/headsmp.S >>> rename arch/arm/mach-bcm/{kona_smp.c => platsmp.c} (63%) >>> >>> diff --git a/arch/arm/mach-bcm/Kconfig b/arch/arm/mach-bcm/Kconfig >>> index 1679fa4..2e9dbb5 100644 >>> --- a/arch/arm/mach-bcm/Kconfig >>> +++ b/arch/arm/mach-bcm/Kconfig >>> @@ -40,6 +40,8 @@ config ARCH_BCM_NSP >>> select ARCH_BCM_IPROC >>> select ARM_ERRATA_754322 >>> select ARM_ERRATA_775420 >>> + select ARM_ERRATA_764369 if SMP >>> + select HAVE_SMP >>> help >>> Support for Broadcom Northstar Plus SoC. >>> Broadcom Northstar Plus family of SoCs are used for switching control >>> diff --git a/arch/arm/mach-bcm/Makefile b/arch/arm/mach-bcm/Makefile >>> index 892261f..36a4ca30 100644 >>> --- a/arch/arm/mach-bcm/Makefile >>> +++ b/arch/arm/mach-bcm/Makefile >>> @@ -14,7 +14,11 @@ >>> obj-$(CONFIG_ARCH_BCM_CYGNUS) += bcm_cygnus.o >>> >>> # Northstar Plus >>> -obj-$(CONFIG_ARCH_BCM_NSP) += bcm_nsp.o >>> +obj-$(CONFIG_ARCH_BCM_NSP) += bcm_nsp.o >>> + >>> +ifeq ($(CONFIG_ARCH_BCM_NSP),y) >>> +obj-$(CONFIG_SMP) += headsmp.o platsmp.o >>> +endif >>> >>> # BCM281XX >>> obj-$(CONFIG_ARCH_BCM_281XX) += board_bcm281xx.o >>> @@ -23,7 +27,7 @@ obj-$(CONFIG_ARCH_BCM_281XX) += board_bcm281xx.o >>> obj-$(CONFIG_ARCH_BCM_21664) += board_bcm21664.o >>> >>> # BCM281XX and BCM21664 SMP support >>> -obj-$(CONFIG_ARCH_BCM_MOBILE_SMP) += kona_smp.o >>> +obj-$(CONFIG_ARCH_BCM_MOBILE_SMP) += platsmp.o >>> >>> # BCM281XX and BCM21664 L2 cache control >>> obj-$(CONFIG_ARCH_BCM_MOBILE_L2_CACHE) += kona_l2_cache.o >>> diff --git a/arch/arm/mach-bcm/bcm_nsp.h b/arch/arm/mach-bcm/bcm_nsp.h >>> new file mode 100644 >>> index 0000000..58e1e80 >>> --- /dev/null >>> +++ b/arch/arm/mach-bcm/bcm_nsp.h >>> @@ -0,0 +1,19 @@ >>> +/* >>> + * Copyright (C) 2015 Broadcom Corporation >>> + * >>> + * This program is free software; you can redistribute it and/or >>> + * modify it under the terms of the GNU General Public License as >>> + * published by the Free Software Foundation version 2. >>> + * >>> + * This program is distributed "as is" WITHOUT ANY WARRANTY of any >>> + * kind, whether express or implied; without even the implied warranty >>> + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the >>> + * GNU General Public License for more details. >>> + */ >>> + >>> +#ifndef __BCM_NSP_H >>> +#define __BCM_NSP_H >>> + >>> +extern void nsp_secondary_startup(void); >>> + >>> +#endif /* __BCM_NSP_H */ >>> diff --git a/arch/arm/mach-bcm/headsmp.S b/arch/arm/mach-bcm/headsmp.S >>> new file mode 100644 >>> index 0000000..0da13b2 >>> --- /dev/null >>> +++ b/arch/arm/mach-bcm/headsmp.S >>> @@ -0,0 +1,37 @@ >>> +/* >>> + * Copyright (C) 2015 Broadcom Corporation >>> + * >>> + * This program is free software; you can redistribute it and/or >>> + * modify it under the terms of the GNU General Public License as >>> + * published by the Free Software Foundation version 2. >>> + * >>> + * This program is distributed "as is" WITHOUT ANY WARRANTY of any >>> + * kind, whether express or implied; without even the implied warranty >>> + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the >>> + * GNU General Public License for more details. >>> + */ >>> + >>> +#include <linux/linkage.h> >>> + >>> +/* >>> + * iProc specific entry point for secondary CPUs. This provides >>> + * a "holding pen" into which all secondary cores are held until >>> + * we are ready for them to initialise. >>> + */ >>> +ENTRY(nsp_secondary_startup) >>> + mrc p15, 0, r0, c0, c0, 5 >>> + and r0, r0, #15 >>> + adr r4, 1f >>> + ldmia r4, {r5, r6} >>> + sub r4, r4, r5 >>> + add r6, r6, r4 >>> +pen: ldr r7, [r6] >>> + cmp r7, r0 >>> + bne pen >>> + >>> + b secondary_startup >>> + >>> +1: .long . >>> + .long pen_release >>> + >>> +ENDPROC(nsp_secondary_startup) >>> diff --git a/arch/arm/mach-bcm/kona_smp.c b/arch/arm/mach-bcm/platsmp.c >>> similarity index 63% >>> rename from arch/arm/mach-bcm/kona_smp.c >>> rename to arch/arm/mach-bcm/platsmp.c >>> index 66a0465..619030e 100644 >>> --- a/arch/arm/mach-bcm/kona_smp.c >>> +++ b/arch/arm/mach-bcm/platsmp.c >>> @@ -1,5 +1,5 @@ >>> /* >>> - * Copyright (C) 2014 Broadcom Corporation >>> + * Copyright (C) 2014-2015 Broadcom Corporation >>> * Copyright 2014 Linaro Limited >>> * >>> * This program is free software; you can redistribute it and/or >>> @@ -12,16 +12,23 @@ >>> * GNU General Public License for more details. >>> */ >>> >>> -#include <linux/init.h> >>> +#include <linux/cpumask.h> >>> +#include <linux/delay.h> >>> #include <linux/errno.h> >>> +#include <linux/init.h> >>> #include <linux/io.h> >>> +#include <linux/jiffies.h> >>> #include <linux/of.h> >>> #include <linux/sched.h> >>> +#include <linux/smp.h> >>> >>> +#include <asm/cacheflush.h> >>> #include <asm/smp.h> >>> #include <asm/smp_plat.h> >>> #include <asm/smp_scu.h> >>> >>> +#include "bcm_nsp.h" >>> + >>> /* Size of mapped Cortex A9 SCU address space */ >>> #define CORTEX_A9_SCU_SIZE 0x58 >>> >>> @@ -34,6 +41,24 @@ >>> /* I/O address of register used to coordinate secondary core startup */ >>> static u32 secondary_boot; >>> >>> +static DEFINE_SPINLOCK(boot_lock); >>> + >>> +/* >>> + * Write pen_release in a way that is guaranteed to be visible to all >>> + * observers, irrespective of whether they're taking part in coherency >>> + * or not. This is necessary for the hotplug code to work reliably. >>> + */ >>> +static void write_pen_release(int val) >>> +{ >>> + pen_release = val; >>> + /* >>> + * Ensure write to pen_release is visible to the other cores, >>> + * here - primary core >>> + */ >>> + smp_wmb(); >>> + sync_cache_w(&pen_release); >>> +} >>> + >>> /* >>> * Enable the Cortex A9 Snoop Control Unit >>> * >>> @@ -75,6 +100,51 @@ static int __init scu_a9_enable(void) >>> return 0; >>> } >>> >>> +static int nsp_write_lut(void (*secondary_startup) (void)) >>> +{ >>> + void __iomem *sku_rom_lut; >>> + phys_addr_t secondary_startup_phy; >>> + >>> + if (!secondary_boot) { >>> + pr_warn("required secondary boot register not specified\n"); >>> + return -EINVAL; >>> + } >>> + >>> + sku_rom_lut = ioremap_nocache((phys_addr_t)secondary_boot, >>> + sizeof(secondary_boot)); >>> + if (!sku_rom_lut) { >>> + pr_warn("unable to ioremap SKU-ROM LUT register\n"); >>> + return -ENOMEM; >>> + } >>> + >>> + secondary_startup_phy = virt_to_phys(secondary_startup); >>> + BUG_ON(secondary_startup_phy > (phys_addr_t)U32_MAX); >>> + >>> + writel_relaxed(secondary_startup_phy, sku_rom_lut); >>> + /* >>> + * Ensure the write is visible to the secondary core. >>> + */ >>> + smp_wmb(); >>> + >>> + iounmap(sku_rom_lut); >>> + >>> + return 0; >>> +} >>> + >>> +static void nsp_secondary_init(unsigned int cpu) >>> +{ >>> + /* >>> + * Let the primary cpu know we are out of holding pen. >>> + */ >>> + write_pen_release(-1); >>> + >>> + /* >>> + * Synchronise with the boot thread. >>> + */ >>> + spin_lock(&boot_lock); >>> + spin_unlock(&boot_lock); >>> +} >>> + >>> static void __init bcm_smp_prepare_cpus(unsigned int max_cpus) >>> { >>> static cpumask_t only_cpu_0 = { CPU_BITS_CPU0 }; >>> @@ -95,11 +165,11 @@ static void __init bcm_smp_prepare_cpus(unsigned int max_cpus) >>> /* >>> * Our secondary enable method requires a "secondary-boot-reg" >>> * property to specify a register address used to request the >>> - * ROM code boot a secondary code. If we have any trouble >>> + * ROM code boot a secondary core. If we have any trouble >>> * getting this we fall back to uniprocessor mode. >>> */ >>> if (of_property_read_u32(node, OF_SECONDARY_BOOT, &secondary_boot)) { >>> - pr_err("%s: missing/invalid " OF_SECONDARY_BOOT " property\n", >>> + pr_warn("%s: missing/invalid " OF_SECONDARY_BOOT " property\n", >>> node->name); >>> ret = -ENOENT; /* Arrange to disable SMP */ >>> goto out; >>> @@ -115,7 +185,6 @@ out: >>> of_node_put(node); >>> if (ret) { >>> /* Update the CPU present map to reflect uniprocessor mode */ >>> - BUG_ON(ret != -ENOENT); >>> pr_warn("disabling SMP\n"); >>> init_cpu_present(&only_cpu_0); >>> } >>> @@ -139,7 +208,7 @@ out: >>> * - Wait for the secondary boot register to be re-written, which >>> * indicates the secondary core has started. >>> */ >>> -static int bcm_boot_secondary(unsigned int cpu, struct task_struct *idle) >>> +static int kona_boot_secondary(unsigned int cpu, struct task_struct *idle) >>> { >>> void __iomem *boot_reg; >>> phys_addr_t boot_func; >>> @@ -162,7 +231,7 @@ static int bcm_boot_secondary(unsigned int cpu, struct task_struct *idle) >>> boot_reg = ioremap_nocache((phys_addr_t)secondary_boot, sizeof(u32)); >>> if (!boot_reg) { >>> pr_err("unable to map boot register for cpu %u\n", cpu_id); >>> - return -ENOSYS; >>> + return -ENOMEM; >>> } >>> >>> /* >>> @@ -191,12 +260,67 @@ static int bcm_boot_secondary(unsigned int cpu, struct task_struct *idle) >>> >>> pr_err("timeout waiting for cpu %u to start\n", cpu_id); >>> >>> - return -ENOSYS; >>> + return -ENXIO; >>> +} >>> + >>> +static int nsp_boot_secondary(unsigned int cpu, struct task_struct *idle) >>> +{ >>> + unsigned long timeout; >>> + int ret; >>> + >>> + /* >>> + * After wake up, secondary core branches to the startup >>> + * address programmed at SKU ROM LUT location. >>> + */ >>> + ret = nsp_write_lut(nsp_secondary_startup); >>> + if (ret) { >>> + pr_err("unable to write startup addr to SKU ROM LUT\n"); >>> + goto out; >>> + } >>> + >>> + /* >>> + * The secondary processor is waiting to be released from >>> + * the holding pen - release it, then wait for it to flag >>> + * that it has been released by resetting pen_release. >>> + */ >>> + spin_lock(&boot_lock); >>> + >>> + write_pen_release(cpu_logical_map(cpu)); >>> + /* >>> + * Send an Event to wake up the secondary core which is in >>> + * WFE state. Updated pen_release should also be visible to >>> + * the secondary core. >>> + */ >>> + dsb_sev(); >>> + >>> + timeout = jiffies + (1 * HZ); >>> + while (time_before(jiffies, timeout)) { >>> + /* Make sure loads on other CPU is visible */ >>> + smp_rmb(); >>> + if (pen_release == -1) >>> + break; >>> + >>> + udelay(10); >>> + } >>> + >>> + spin_unlock(&boot_lock); >> >> Why is this boot_lock needed? As far as I understand it asserts that >> both CPUs leave nsp_boot_secondary() and nsp_secondary_init() at the >> same time. >> > It makes sure secondary cpu doesn't run away before primary cpu > recognizes the presence of secondary cpu, it is a way of > synchronization between primary and secondary cpu. This is the > method used across many SoCs. >>> + >>> + ret = pen_release != -1 ? -ENXIO : 0; >>> + >>> +out: >>> + return ret; >>> } >>> >>> static struct smp_operations bcm_smp_ops __initdata = { >>> .smp_prepare_cpus = bcm_smp_prepare_cpus, >>> - .smp_boot_secondary = bcm_boot_secondary, >>> + .smp_boot_secondary = kona_boot_secondary, >>> }; >>> CPU_METHOD_OF_DECLARE(bcm_smp_bcm281xx, "brcm,bcm11351-cpu-method", >>> &bcm_smp_ops); >>> + >>> +struct smp_operations nsp_smp_ops __initdata = { >>> + .smp_prepare_cpus = bcm_smp_prepare_cpus, >>> + .smp_secondary_init = nsp_secondary_init, >>> + .smp_boot_secondary = nsp_boot_secondary, >>> +}; >>> +CPU_METHOD_OF_DECLARE(bcm_smp_nsp, "brcm,bcm-nsp-smp", &nsp_smp_ops); >>> >> > Thanks, > Kapil > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html