[PATCH v16 2/9] ARM: hisi: enable MCPM implementation
Nicolas Pitre
nicolas.pitre at linaro.org
Mon Aug 4 15:43:38 PDT 2014
Sorry for the delay -- I was on vacation.
On Mon, 4 Aug 2014, Haojian Zhuang wrote:
> Multiple CPU clusters are used in Hisilicon HiP04 SoC. Now use MCPM
> framework to manage power on HiP04 SoC.
>
> Changelog:
> v16:
> * Parse bootwrapper parameters in command line instead.
What is that about? I don't particularly like to see bootloader
handshake details passed to the kernel via the kernel command line
mechanism. Given this looks like special memory regions, can't they be
specified via the device tree instead?
> v13:
> * Restore power down operation in MCPM.
> * Fix disabling snoop filter issue in MCPM.
> v12:
> * Use wfi as power down state in MCPM.
> * Remove wait_for_powerdown() in MCPM because wfi is used now.
>
> Signed-off-by: Haojian Zhuang <haojian.zhuang at linaro.org>
More comments below.
> ---
> arch/arm/mach-hisi/Makefile | 1 +
> arch/arm/mach-hisi/platmcpm.c | 374 ++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 375 insertions(+)
> create mode 100644 arch/arm/mach-hisi/platmcpm.c
>
> diff --git a/arch/arm/mach-hisi/Makefile b/arch/arm/mach-hisi/Makefile
> index ee2506b..d64831e 100644
> --- a/arch/arm/mach-hisi/Makefile
> +++ b/arch/arm/mach-hisi/Makefile
> @@ -3,4 +3,5 @@
> #
>
> obj-y += hisilicon.o
> +obj-$(CONFIG_MCPM) += platmcpm.o
> obj-$(CONFIG_SMP) += platsmp.o hotplug.o headsmp.o
> diff --git a/arch/arm/mach-hisi/platmcpm.c b/arch/arm/mach-hisi/platmcpm.c
> new file mode 100644
> index 0000000..fc17973
> --- /dev/null
> +++ b/arch/arm/mach-hisi/platmcpm.c
> @@ -0,0 +1,374 @@
> +/*
> + * Copyright (c) 2013-2014 Linaro Ltd.
> + * Copyright (c) 2013-2014 Hisilicon Limited.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + */
> +#include <linux/delay.h>
> +#include <linux/io.h>
> +#include <linux/memblock.h>
> +#include <linux/of_address.h>
> +
> +#include <asm/cputype.h>
> +#include <asm/cp15.h>
> +#include <asm/mcpm.h>
> +
> +#include "core.h"
> +
> +/* bits definition in SC_CPU_RESET_REQ[x]/SC_CPU_RESET_DREQ[x]
> + * 1 -- unreset; 0 -- reset
> + */
> +#define CORE_RESET_BIT(x) (1 << x)
> +#define NEON_RESET_BIT(x) (1 << (x + 4))
> +#define CORE_DEBUG_RESET_BIT(x) (1 << (x + 9))
> +#define CLUSTER_L2_RESET_BIT (1 << 8)
> +#define CLUSTER_DEBUG_RESET_BIT (1 << 13)
> +
> +/*
> + * bits definition in SC_CPU_RESET_STATUS[x]
> + * 1 -- reset status; 0 -- unreset status
> + */
> +#define CORE_RESET_STATUS(x) (1 << x)
> +#define NEON_RESET_STATUS(x) (1 << (x + 4))
> +#define CORE_DEBUG_RESET_STATUS(x) (1 << (x + 9))
> +#define CLUSTER_L2_RESET_STATUS (1 << 8)
> +#define CLUSTER_DEBUG_RESET_STATUS (1 << 13)
> +#define CORE_WFI_STATUS(x) (1 << (x + 16))
> +#define CORE_WFE_STATUS(x) (1 << (x + 20))
> +#define CORE_DEBUG_ACK(x) (1 << (x + 24))
> +
> +#define SC_CPU_RESET_REQ(x) (0x520 + (x << 3)) /* reset */
> +#define SC_CPU_RESET_DREQ(x) (0x524 + (x << 3)) /* unreset */
> +#define SC_CPU_RESET_STATUS(x) (0x1520 + (x << 3))
> +
> +#define FAB_SF_MODE 0x0c
> +#define FAB_SF_INVLD 0x10
> +
> +/* bits definition in FB_SF_INVLD */
> +#define FB_SF_INVLD_START (1 << 8)
> +
> +#define HIP04_MAX_CLUSTERS 4
> +#define HIP04_MAX_CPUS_PER_CLUSTER 4
> +
> +#define POLL_MSEC 10
> +#define TIMEOUT_MSEC 1000
> +
> +struct hip04_secondary_cpu_data {
> + u32 bootwrapper_phys;
> + u32 bootwrapper_size;
> + u32 bootwrapper_magic;
> + u32 relocation_entry;
> + u32 relocation_size;
> +};
> +
> +static void __iomem *relocation, *sysctrl, *fabric;
> +static int hip04_cpu_table[HIP04_MAX_CLUSTERS][HIP04_MAX_CPUS_PER_CLUSTER];
> +static DEFINE_SPINLOCK(boot_lock);
> +static struct hip04_secondary_cpu_data hip04_boot;
> +static u32 fabric_phys_addr;
> +
> +static int __init hip04_parse_bootwrapper(char *p)
> +{
> + int data[4];
> +
> + get_options(p, ARRAY_SIZE(data), &data[0]);
> + if (!data[0] || (data[0] < 3)) {
> + pr_err("fail to parse bootwrapper parameters\n");
> + return -EINVAL;
> + }
> + hip04_boot.bootwrapper_phys = data[1];
> + hip04_boot.bootwrapper_size = data[2];
> + hip04_boot.bootwrapper_magic = data[3];
> + memblock_reserve(data[1], data[2]);
What if memblock_reserve() fails? You should at least avoid initializing
hip04_boot in that case.
> + return 0;
> +}
> +early_param("bootwrapper", hip04_parse_bootwrapper);
> +
> +static int __init hip04_parse_relocation(char *p)
> +{
> + int data[3];
> +
> + get_options(p, ARRAY_SIZE(data), &data[0]);
> + if (!data[0] || (data[0] < 2)) {
> + pr_err("fail to parse relocation parameters\n");
> + return -EINVAL;
> + }
> + hip04_boot.relocation_entry = data[1];
> + hip04_boot.relocation_size = data[2];
> + return 0;
> +}
> +early_param("relocation", hip04_parse_relocation);
> +
> +static bool hip04_cluster_down(unsigned int cluster)
I'd suggest renaming this into hip04_cluster_is_down() as it only
returns a state and performs no action.
> +{
> + int i;
> +
> + for (i = 0; i < HIP04_MAX_CPUS_PER_CLUSTER; i++)
> + if (hip04_cpu_table[cluster][i])
> + return false;
> + return true;
> +}
> +
> +static void hip04_set_snoop_filter(unsigned int cluster, unsigned int on)
> +{
> + unsigned long data;
> +
> + if (!fabric)
> + BUG();
> + data = readl_relaxed(fabric + FAB_SF_MODE);
> + if (on)
> + data |= 1 << cluster;
> + else
> + data &= ~(1 << cluster);
> + writel_relaxed(data, fabric + FAB_SF_MODE);
> + while (1) {
> + if (data == readl_relaxed(fabric + FAB_SF_MODE))
> + break;
> + }
> + return;
> +}
> +
> +static int hip04_mcpm_power_up(unsigned int cpu, unsigned int cluster)
> +{
> + unsigned long data, mask;
> +
> + if (!relocation || !sysctrl)
> + return -ENODEV;
> + if (cluster >= HIP04_MAX_CLUSTERS || cpu >= HIP04_MAX_CPUS_PER_CLUSTER)
> + return -EINVAL;
> +
> + spin_lock_irq(&boot_lock);
> +
> + if (hip04_cpu_table[cluster][cpu])
> + goto out;
> +
> + /* Make secondary core out of reset. */
> + writel_relaxed(hip04_boot.bootwrapper_phys, relocation);
> + writel_relaxed(hip04_boot.bootwrapper_magic, relocation + 4);
> + writel_relaxed(virt_to_phys(mcpm_entry_point), relocation + 8);
> + writel_relaxed(0, relocation + 12);
> +
> + if (hip04_cluster_down(cluster)) {
> + data = CLUSTER_DEBUG_RESET_BIT;
> + writel_relaxed(data, sysctrl + SC_CPU_RESET_DREQ(cluster));
> + do {
Inserting a cpu_relax() right here wouldn't hurt.
> + mask = CLUSTER_DEBUG_RESET_STATUS;
> + data = readl_relaxed(sysctrl + \
> + SC_CPU_RESET_STATUS(cluster));
> + } while (data & mask);
> + }
> +
> + data = CORE_RESET_BIT(cpu) | NEON_RESET_BIT(cpu) | \
> + CORE_DEBUG_RESET_BIT(cpu);
> + writel_relaxed(data, sysctrl + SC_CPU_RESET_DREQ(cluster));
> +out:
> + hip04_cpu_table[cluster][cpu]++;
> + spin_unlock_irq(&boot_lock);
> +
> + return 0;
> +}
> +
> +static void hip04_mcpm_power_down(void)
> +{
> + unsigned int mpidr, cpu, cluster;
> + bool skip_wfi = false;
> +
> + mpidr = read_cpuid_mpidr();
> + cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
> + cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
> +
> + __mcpm_cpu_going_down(cpu, cluster);
> +
> + spin_lock(&boot_lock);
> + BUG_ON(__mcpm_cluster_state(cluster) != CLUSTER_UP);
> + hip04_cpu_table[cluster][cpu]--;
> + if (hip04_cpu_table[cluster][cpu] == 1) {
> + /* A power_up request went ahead of us. */
> + skip_wfi = true;
> + } else if (hip04_cpu_table[cluster][cpu] > 1) {
> + pr_err("Cluster %d CPU%d boots multiple times\n", cluster, cpu);
> + BUG();
> + }
> + spin_unlock(&boot_lock);
> +
> + v7_exit_coherency_flush(louis);
If this is the last man, the whole cache must be flushed with
v7_exit_coherency_flush(all).
> +
> + __mcpm_cpu_down(cpu, cluster);
> +
> + if (!skip_wfi)
> + wfi();
> +}
> +
> +static int hip04_mcpm_wait_for_powerdown(unsigned int cpu, unsigned int cluster)
> +{
> + unsigned int data, tries, count;
> +
> + BUG_ON(cluster >= HIP04_MAX_CLUSTERS ||
> + cpu >= HIP04_MAX_CPUS_PER_CLUSTER);
> +
> + count = TIMEOUT_MSEC / POLL_MSEC;
> + spin_lock(&boot_lock);
> + for (tries = 0; tries < count; tries++) {
> + data = readl_relaxed(sysctrl + SC_CPU_RESET_STATUS(cluster));
> + if (!(data & CORE_WFI_STATUS(cpu))) {
> + msleep(POLL_MSEC);
You can't sleep while holding a lock.
> + continue;
> + }
> + }
> + if (tries >= count)
> + goto err;
> + data = CORE_RESET_BIT(cpu) | NEON_RESET_BIT(cpu) | \
> + CORE_DEBUG_RESET_BIT(cpu);
> + writel_relaxed(data, sysctrl + SC_CPU_RESET_REQ(cluster));
> + for (tries = 0; tries < count; tries++) {
> + data = readl_relaxed(sysctrl + SC_CPU_RESET_STATUS(cluster));
> + if (!(data & CORE_RESET_STATUS(cpu))) {
> + msleep(POLL_MSEC);
Same here.
Also I don't really like the way this MCPM method is abused to shut down
a CPU because the target CPU can't do it on its own. We're getting back
to this again and I suppose this is because the hardware is not able to
do otherwise. However this mysterious CORE_WFI_STATUS bit made its
apparition lately, so one may speculate that the hardware might be able
to do more than it may seem. The lack of (english) documentation is
really making a more optimal implementation impossible at this point. So
I'll give in and let this pass but not without a sufficiently
comprehensive comment in the code to that effect.
Now... around msleep calls you have to drop and reacquire the lock.
And when the lock is reacquired you should check that the CPU count is
still 0 and bail out otherwise so not to mess up with a concurrent
cpu_up(). This won't be enough to prevent a race against asynchronous
wake-ups though, but you are not doing any of that yet. That too would
need to be documented in that comment.
> + continue;
> + }
> + }
> + if (tries >= count)
> + goto err;
> + if (hip04_cluster_down(cluster))
> + hip04_set_snoop_filter(cluster, 0);
> + spin_unlock(&boot_lock);
Oh, and that ought to be spin_lock_irq()/spin_unlock_irq() here.
> + return 0;
> +err:
> + spin_unlock(&boot_lock);
> + return -ETIMEDOUT;
> +}
> +
> +static void hip04_mcpm_powered_up(void)
> +{
> + if (!relocation)
> + return;
> + spin_lock(&boot_lock);
> + writel_relaxed(0, relocation);
> + writel_relaxed(0, relocation + 4);
> + writel_relaxed(0, relocation + 8);
> + writel_relaxed(0, relocation + 12);
> + spin_unlock(&boot_lock);
> +}
> +
> +static void __naked hip04_mcpm_power_up_setup(unsigned int affinity_level)
> +{
> + asm volatile (" \n"
> +" cmp r0, #0 \n"
> +" bxeq lr \n"
> + /* calculate fabric phys address */
> +" adr r2, 2f \n"
> +" ldmia r2, {r1, r3} \n"
> +" sub r0, r2, r1 \n"
> +" ldr r2, [r0, r3] \n"
> + /* get cluster id from MPIDR */
> +" mrc p15, 0, r0, c0, c0, 5 \n"
> +" ubfx r1, r0, #8, #8 \n"
> + /* 1 << cluster id */
> +" mov r0, #1 \n"
> +" mov r3, r0, lsl r1 \n"
> +" ldr r0, [r2, #"__stringify(FAB_SF_MODE)"] \n"
> +" tst r0, r3 \n"
> +" bxne lr \n"
> +" orr r1, r0, r3 \n"
> +" str r1, [r2, #"__stringify(FAB_SF_MODE)"] \n"
> +"1: ldr r0, [r2, #"__stringify(FAB_SF_MODE)"] \n"
> +" tst r0, r3 \n"
> +" beq 1b \n"
> +" bx lr \n"
> +
> +" .align 2 \n"
> +"2: .word . \n"
> +" .word fabric_phys_addr \n"
> + );
> +}
> +
> +static const struct mcpm_platform_ops hip04_mcpm_ops = {
> + .power_up = hip04_mcpm_power_up,
> + .power_down = hip04_mcpm_power_down,
> + .wait_for_powerdown = hip04_mcpm_wait_for_powerdown,
> + .powered_up = hip04_mcpm_powered_up,
> +};
> +
> +static bool __init hip04_cpu_table_init(void)
> +{
> + unsigned int mpidr, cpu, cluster;
> +
> + mpidr = read_cpuid_mpidr();
> + cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
> + cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
> +
> + if (cluster >= HIP04_MAX_CLUSTERS ||
> + cpu >= HIP04_MAX_CPUS_PER_CLUSTER) {
> + pr_err("%s: boot CPU is out of bound!\n", __func__);
> + return false;
> + }
> + hip04_set_snoop_filter(0, 1);
This should be hip04_set_snoop_filter(cluster, 1).
> + hip04_cpu_table[cluster][cpu] = 1;
> + return true;
> +}
> +
> +static int __init hip04_mcpm_init(void)
> +{
> + struct device_node *np, *np_fab;
> + struct resource fab_res;
> + int ret = -ENODEV;
> +
> + if (!hip04_boot.bootwrapper_phys || !hip04_boot.relocation_entry) {
> + pr_err("fail to find bootwrapper or relocation param\n");
> + ret = -EINVAL;
> + goto err;
> + }
> +
> + np = of_find_compatible_node(NULL, NULL, "hisilicon,sysctrl");
> + if (!np)
> + goto err;
> + np_fab = of_find_compatible_node(NULL, NULL, "hisilicon,hip04-fabric");
> + if (!np_fab)
> + goto err;
> +
> + relocation = ioremap(hip04_boot.relocation_entry,
> + hip04_boot.relocation_size);
> + if (!relocation) {
> + pr_err("failed to map relocation space\n");
> + ret = -ENOMEM;
> + goto err;
> + }
> + sysctrl = of_iomap(np, 0);
> + if (!sysctrl) {
> + pr_err("failed to get sysctrl base\n");
> + ret = -ENOMEM;
> + goto err_sysctrl;
> + }
> + ret = of_address_to_resource(np_fab, 0, &fab_res);
> + if (ret) {
> + pr_err("failed to get fabric base phys\n");
> + goto err_fabric;
> + }
> + fabric_phys_addr = fab_res.start;
> + sync_cache_w(&fabric_phys_addr);
> + fabric = of_iomap(np_fab, 0);
> + if (!fabric) {
> + pr_err("failed to get fabric base\n");
> + ret = -ENOMEM;
> + goto err_fabric;
> + }
> +
> + if (!hip04_cpu_table_init())
> + return -EINVAL;
> + ret = mcpm_platform_register(&hip04_mcpm_ops);
> + if (!ret) {
> + mcpm_sync_init(hip04_mcpm_power_up_setup);
> + pr_info("HiP04 MCPM initialized\n");
> + }
> + mcpm_smp_set_ops();
This mcpm_smp_set_ops() should be called only if MCPM registration is
successful i.e. right after mcpm_sync_init inside the if conditional
above.
> + return ret;
> +err_fabric:
> + iounmap(sysctrl);
> +err_sysctrl:
> + iounmap(relocation);
> +err:
> + return ret;
> +}
> +early_initcall(hip04_mcpm_init);
> --
> 1.9.1
>
>
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