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ARM: sun9i: Support SMP bring-up on A80

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The A80 is a big.LITTLE SoC with 1 cluster of 4 Cortex-A7s and
1 cluster of 4 Cortex-A15s.

This patch adds support to bring up the second cluster and thus all
cores using custom platform SMP code. Core/cluster power down has not
been implemented, thus CPU hotplugging is not supported.

Parts of the trampoline and re-entry code for the boot cpu was adapted
from the MCPM framework.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
This commit is contained in:
Chen-Yu Tsai 2018-01-17 16:46:47 +08:00
parent 7928b2cbe5
commit 745373e3d6
3 changed files with 560 additions and 0 deletions
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7
arch/arm/mach-sunxi/Kconfig
View File

@ -48,4 +48,11 @@ config MACH_SUN9I
default ARCH_SUNXI
select ARM_GIC
config ARCH_SUNXI_MC_SMP
bool
depends on SMP
default MACH_SUN9I
select ARM_CCI400_PORT_CTRL
select ARM_CPU_SUSPEND
endif

3
arch/arm/mach-sunxi/Makefile
View File

@ -1,2 +1,5 @@
CFLAGS_mc_smp.o += -march=armv7-a
obj-$(CONFIG_ARCH_SUNXI) += sunxi.o
obj-$(CONFIG_ARCH_SUNXI_MC_SMP) += mc_smp.o
obj-$(CONFIG_SMP) += platsmp.o

550
arch/arm/mach-sunxi/mc_smp.c Normal file
View File

@ -0,0 +1,550 @@
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2018 Chen-Yu Tsai
*
* Chen-Yu Tsai <wens@csie.org>
*
* arch/arm/mach-sunxi/mc_smp.c
*
* Based on Allwinner code, arch/arm/mach-exynos/mcpm-exynos.c, and
* arch/arm/mach-hisi/platmcpm.c
* Cluster cache enable trampoline code adapted from MCPM framework
*/
#include <linux/arm-cci.h>
#include <linux/cpu_pm.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/smp.h>
#include <asm/cacheflush.h>
#include <asm/cp15.h>
#include <asm/cputype.h>
#include <asm/idmap.h>
#include <asm/smp_plat.h>
#include <asm/suspend.h>
#define SUNXI_CPUS_PER_CLUSTER 4
#define SUNXI_NR_CLUSTERS 2
#define CPUCFG_CX_CTRL_REG0(c) (0x10 * (c))
#define CPUCFG_CX_CTRL_REG0_L1_RST_DISABLE(n) BIT(n)
#define CPUCFG_CX_CTRL_REG0_L1_RST_DISABLE_ALL 0xf
#define CPUCFG_CX_CTRL_REG0_L2_RST_DISABLE_A7 BIT(4)
#define CPUCFG_CX_CTRL_REG0_L2_RST_DISABLE_A15 BIT(0)
#define CPUCFG_CX_CTRL_REG1(c) (0x10 * (c) + 0x4)
#define CPUCFG_CX_CTRL_REG1_ACINACTM BIT(0)
#define CPUCFG_CX_RST_CTRL(c) (0x80 + 0x4 * (c))
#define CPUCFG_CX_RST_CTRL_DBG_SOC_RST BIT(24)
#define CPUCFG_CX_RST_CTRL_ETM_RST(n) BIT(20 + (n))
#define CPUCFG_CX_RST_CTRL_ETM_RST_ALL (0xf << 20)
#define CPUCFG_CX_RST_CTRL_DBG_RST(n) BIT(16 + (n))
#define CPUCFG_CX_RST_CTRL_DBG_RST_ALL (0xf << 16)
#define CPUCFG_CX_RST_CTRL_H_RST BIT(12)
#define CPUCFG_CX_RST_CTRL_L2_RST BIT(8)
#define CPUCFG_CX_RST_CTRL_CX_RST(n) BIT(4 + (n))
#define CPUCFG_CX_RST_CTRL_CORE_RST(n) BIT(n)
#define PRCM_CPU_PO_RST_CTRL(c) (0x4 + 0x4 * (c))
#define PRCM_CPU_PO_RST_CTRL_CORE(n) BIT(n)
#define PRCM_CPU_PO_RST_CTRL_CORE_ALL 0xf
#define PRCM_PWROFF_GATING_REG(c) (0x100 + 0x4 * (c))
#define PRCM_PWROFF_GATING_REG_CLUSTER BIT(4)
#define PRCM_PWROFF_GATING_REG_CORE(n) BIT(n)
#define PRCM_PWR_SWITCH_REG(c, cpu) (0x140 + 0x10 * (c) + 0x4 * (cpu))
#define PRCM_CPU_SOFT_ENTRY_REG 0x164
static void __iomem *cpucfg_base;
static void __iomem *prcm_base;
static bool sunxi_core_is_cortex_a15(unsigned int core, unsigned int cluster)
{
struct device_node *node;
int cpu = cluster * SUNXI_CPUS_PER_CLUSTER + core;
node = of_cpu_device_node_get(cpu);
/* In case of_cpu_device_node_get fails */
if (!node)
node = of_get_cpu_node(cpu, NULL);
if (!node) {
/*
* There's no point in returning an error, since we
* would be mid way in a core or cluster power sequence.
*/
pr_err("%s: Couldn't get CPU cluster %u core %u device node\n",
__func__, cluster, core);
return false;
}
return of_device_is_compatible(node, "arm,cortex-a15");
}
static int sunxi_cpu_power_switch_set(unsigned int cpu, unsigned int cluster,
bool enable)
{
u32 reg;
/* control sequence from Allwinner A80 user manual v1.2 PRCM section */
reg = readl(prcm_base + PRCM_PWR_SWITCH_REG(cluster, cpu));
if (enable) {
if (reg == 0x00) {
pr_debug("power clamp for cluster %u cpu %u already open\n",
cluster, cpu);
return 0;
}
writel(0xff, prcm_base + PRCM_PWR_SWITCH_REG(cluster, cpu));
udelay(10);
writel(0xfe, prcm_base + PRCM_PWR_SWITCH_REG(cluster, cpu));
udelay(10);
writel(0xf8, prcm_base + PRCM_PWR_SWITCH_REG(cluster, cpu));
udelay(10);
writel(0xf0, prcm_base + PRCM_PWR_SWITCH_REG(cluster, cpu));
udelay(10);
writel(0x00, prcm_base + PRCM_PWR_SWITCH_REG(cluster, cpu));
udelay(10);
} else {
writel(0xff, prcm_base + PRCM_PWR_SWITCH_REG(cluster, cpu));
udelay(10);
}
return 0;
}
static int sunxi_cpu_powerup(unsigned int cpu, unsigned int cluster)
{
u32 reg;
pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
if (cpu >= SUNXI_CPUS_PER_CLUSTER || cluster >= SUNXI_NR_CLUSTERS)
return -EINVAL;
/* assert processor power-on reset */
reg = readl(prcm_base + PRCM_CPU_PO_RST_CTRL(cluster));
reg &= ~PRCM_CPU_PO_RST_CTRL_CORE(cpu);
writel(reg, prcm_base + PRCM_CPU_PO_RST_CTRL(cluster));
/* Cortex-A7: hold L1 reset disable signal low */
if (!sunxi_core_is_cortex_a15(cpu, cluster)) {
reg = readl(cpucfg_base + CPUCFG_CX_CTRL_REG0(cluster));
reg &= ~CPUCFG_CX_CTRL_REG0_L1_RST_DISABLE(cpu);
writel(reg, cpucfg_base + CPUCFG_CX_CTRL_REG0(cluster));
}
/* assert processor related resets */
reg = readl(cpucfg_base + CPUCFG_CX_RST_CTRL(cluster));
reg &= ~CPUCFG_CX_RST_CTRL_DBG_RST(cpu);
/*
* Allwinner code also asserts resets for NEON on A15. According
* to ARM manuals, asserting power-on reset is sufficient.
*/
if (!sunxi_core_is_cortex_a15(cpu, cluster))
reg &= ~CPUCFG_CX_RST_CTRL_ETM_RST(cpu);
writel(reg, cpucfg_base + CPUCFG_CX_RST_CTRL(cluster));
/* open power switch */
sunxi_cpu_power_switch_set(cpu, cluster, true);
/* clear processor power gate */
reg = readl(prcm_base + PRCM_PWROFF_GATING_REG(cluster));
reg &= ~PRCM_PWROFF_GATING_REG_CORE(cpu);
writel(reg, prcm_base + PRCM_PWROFF_GATING_REG(cluster));
udelay(20);
/* de-assert processor power-on reset */
reg = readl(prcm_base + PRCM_CPU_PO_RST_CTRL(cluster));
reg |= PRCM_CPU_PO_RST_CTRL_CORE(cpu);
writel(reg, prcm_base + PRCM_CPU_PO_RST_CTRL(cluster));
/* de-assert all processor resets */
reg = readl(cpucfg_base + CPUCFG_CX_RST_CTRL(cluster));
reg |= CPUCFG_CX_RST_CTRL_DBG_RST(cpu);
reg |= CPUCFG_CX_RST_CTRL_CORE_RST(cpu);
if (!sunxi_core_is_cortex_a15(cpu, cluster))
reg |= CPUCFG_CX_RST_CTRL_ETM_RST(cpu);
else
reg |= CPUCFG_CX_RST_CTRL_CX_RST(cpu); /* NEON */
writel(reg, cpucfg_base + CPUCFG_CX_RST_CTRL(cluster));
return 0;
}
static int sunxi_cluster_powerup(unsigned int cluster)
{
u32 reg;
pr_debug("%s: cluster %u\n", __func__, cluster);
if (cluster >= SUNXI_NR_CLUSTERS)
return -EINVAL;
/* assert ACINACTM */
reg = readl(cpucfg_base + CPUCFG_CX_CTRL_REG1(cluster));
reg |= CPUCFG_CX_CTRL_REG1_ACINACTM;
writel(reg, cpucfg_base + CPUCFG_CX_CTRL_REG1(cluster));
/* assert cluster processor power-on resets */
reg = readl(prcm_base + PRCM_CPU_PO_RST_CTRL(cluster));
reg &= ~PRCM_CPU_PO_RST_CTRL_CORE_ALL;
writel(reg, prcm_base + PRCM_CPU_PO_RST_CTRL(cluster));
/* assert cluster resets */
reg = readl(cpucfg_base + CPUCFG_CX_RST_CTRL(cluster));
reg &= ~CPUCFG_CX_RST_CTRL_DBG_SOC_RST;
reg &= ~CPUCFG_CX_RST_CTRL_DBG_RST_ALL;
reg &= ~CPUCFG_CX_RST_CTRL_H_RST;
reg &= ~CPUCFG_CX_RST_CTRL_L2_RST;
/*
* Allwinner code also asserts resets for NEON on A15. According
* to ARM manuals, asserting power-on reset is sufficient.
*/
if (!sunxi_core_is_cortex_a15(0, cluster))
reg &= ~CPUCFG_CX_RST_CTRL_ETM_RST_ALL;
writel(reg, cpucfg_base + CPUCFG_CX_RST_CTRL(cluster));
/* hold L1/L2 reset disable signals low */
reg = readl(cpucfg_base + CPUCFG_CX_CTRL_REG0(cluster));
if (sunxi_core_is_cortex_a15(0, cluster)) {
/* Cortex-A15: hold L2RSTDISABLE low */
reg &= ~CPUCFG_CX_CTRL_REG0_L2_RST_DISABLE_A15;
} else {
/* Cortex-A7: hold L1RSTDISABLE and L2RSTDISABLE low */
reg &= ~CPUCFG_CX_CTRL_REG0_L1_RST_DISABLE_ALL;
reg &= ~CPUCFG_CX_CTRL_REG0_L2_RST_DISABLE_A7;
}
writel(reg, cpucfg_base + CPUCFG_CX_CTRL_REG0(cluster));
/* clear cluster power gate */
reg = readl(prcm_base + PRCM_PWROFF_GATING_REG(cluster));
reg &= ~PRCM_PWROFF_GATING_REG_CLUSTER;
writel(reg, prcm_base + PRCM_PWROFF_GATING_REG(cluster));
udelay(20);
/* de-assert cluster resets */
reg = readl(cpucfg_base + CPUCFG_CX_RST_CTRL(cluster));
reg |= CPUCFG_CX_RST_CTRL_DBG_SOC_RST;
reg |= CPUCFG_CX_RST_CTRL_H_RST;
reg |= CPUCFG_CX_RST_CTRL_L2_RST;
writel(reg, cpucfg_base + CPUCFG_CX_RST_CTRL(cluster));
/* de-assert ACINACTM */
reg = readl(cpucfg_base + CPUCFG_CX_CTRL_REG1(cluster));
reg &= ~CPUCFG_CX_CTRL_REG1_ACINACTM;
writel(reg, cpucfg_base + CPUCFG_CX_CTRL_REG1(cluster));
return 0;
}
/*
* This bit is shared between the initial nocache_trampoline call to
* enable CCI-400 and proper cluster cache disable before power down.
*/
static void sunxi_cluster_cache_disable_without_axi(void)
{
if (read_cpuid_part() == ARM_CPU_PART_CORTEX_A15) {
/*
* On the Cortex-A15 we need to disable
* L2 prefetching before flushing the cache.
*/
asm volatile(
"mcr p15, 1, %0, c15, c0, 3\n"
"isb\n"
"dsb"
: : "r" (0x400));
}
/* Flush all cache levels for this cluster. */
v7_exit_coherency_flush(all);
/*
* Disable cluster-level coherency by masking
* incoming snoops and DVM messages:
*/
cci_disable_port_by_cpu(read_cpuid_mpidr());
}
static int sunxi_mc_smp_cpu_table[SUNXI_NR_CLUSTERS][SUNXI_CPUS_PER_CLUSTER];
static int sunxi_mc_smp_first_comer;
/*
* Enable cluster-level coherency, in preparation for turning on the MMU.
*
* Also enable regional clock gating and L2 data latency settings for
* Cortex-A15. These settings are from the vendor kernel.
*/
static void __naked sunxi_mc_smp_cluster_cache_enable(void)
{
asm volatile (
"mrc p15, 0, r1, c0, c0, 0\n"
"movw r2, #" __stringify(ARM_CPU_PART_MASK & 0xffff) "\n"
"movt r2, #" __stringify(ARM_CPU_PART_MASK >> 16) "\n"
"and r1, r1, r2\n"
"movw r2, #" __stringify(ARM_CPU_PART_CORTEX_A15 & 0xffff) "\n"
"movt r2, #" __stringify(ARM_CPU_PART_CORTEX_A15 >> 16) "\n"
"cmp r1, r2\n"
"bne not_a15\n"
/* The following is Cortex-A15 specific */
/* ACTLR2: Enable CPU regional clock gates */
"mrc p15, 1, r1, c15, c0, 4\n"
"orr r1, r1, #(0x1<<31)\n"
"mcr p15, 1, r1, c15, c0, 4\n"
/* L2ACTLR */
"mrc p15, 1, r1, c15, c0, 0\n"
/* Enable L2, GIC, and Timer regional clock gates */
"orr r1, r1, #(0x1<<26)\n"
/* Disable clean/evict from being pushed to external */
"orr r1, r1, #(0x1<<3)\n"
"mcr p15, 1, r1, c15, c0, 0\n"
/* L2CTRL: L2 data RAM latency */
"mrc p15, 1, r1, c9, c0, 2\n"
"bic r1, r1, #(0x7<<0)\n"
"orr r1, r1, #(0x3<<0)\n"
"mcr p15, 1, r1, c9, c0, 2\n"
/* End of Cortex-A15 specific setup */
"not_a15:\n"
/* Get value of sunxi_mc_smp_first_comer */
"adr r1, first\n"
"ldr r0, [r1]\n"
"ldr r0, [r1, r0]\n"
/* Skip cci_enable_port_for_self if not first comer */
"cmp r0, #0\n"
"bxeq lr\n"
"b cci_enable_port_for_self\n"
".align 2\n"
"first: .word sunxi_mc_smp_first_comer - .\n"
);
}
static void __naked sunxi_mc_smp_secondary_startup(void)
{
asm volatile(
"bl sunxi_mc_smp_cluster_cache_enable\n"
"b secondary_startup"
/* Let compiler know about sunxi_mc_smp_cluster_cache_enable */
:: "i" (sunxi_mc_smp_cluster_cache_enable)
);
}
static DEFINE_SPINLOCK(boot_lock);
static bool sunxi_mc_smp_cluster_is_down(unsigned int cluster)
{
int i;
for (i = 0; i < SUNXI_CPUS_PER_CLUSTER; i++)
if (sunxi_mc_smp_cpu_table[cluster][i])
return false;
return true;
}
static int sunxi_mc_smp_boot_secondary(unsigned int l_cpu, struct task_struct *idle)
{
unsigned int mpidr, cpu, cluster;
mpidr = cpu_logical_map(l_cpu);
cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
if (!cpucfg_base)
return -ENODEV;
if (cluster >= SUNXI_NR_CLUSTERS || cpu >= SUNXI_CPUS_PER_CLUSTER)
return -EINVAL;
spin_lock_irq(&boot_lock);
if (sunxi_mc_smp_cpu_table[cluster][cpu])
goto out;
if (sunxi_mc_smp_cluster_is_down(cluster)) {
sunxi_mc_smp_first_comer = true;
sunxi_cluster_powerup(cluster);
} else {
sunxi_mc_smp_first_comer = false;
}
/* This is read by incoming CPUs with their cache and MMU disabled */
sync_cache_w(&sunxi_mc_smp_first_comer);
sunxi_cpu_powerup(cpu, cluster);
out:
sunxi_mc_smp_cpu_table[cluster][cpu]++;
spin_unlock_irq(&boot_lock);
return 0;
}
static const struct smp_operations sunxi_mc_smp_smp_ops __initconst = {
.smp_boot_secondary = sunxi_mc_smp_boot_secondary,
};
static bool __init sunxi_mc_smp_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 >= SUNXI_NR_CLUSTERS || cpu >= SUNXI_CPUS_PER_CLUSTER) {
pr_err("%s: boot CPU is out of bounds!\n", __func__);
return false;
}
sunxi_mc_smp_cpu_table[cluster][cpu] = 1;
return true;
}
/*
* Adapted from arch/arm/common/mc_smp_entry.c
*
* We need the trampoline code to enable CCI-400 on the first cluster
*/
typedef typeof(cpu_reset) phys_reset_t;
static void __init __naked sunxi_mc_smp_resume(void)
{
asm volatile(
"bl sunxi_mc_smp_cluster_cache_enable\n"
"b cpu_resume"
/* Let compiler know about sunxi_mc_smp_cluster_cache_enable */
:: "i" (sunxi_mc_smp_cluster_cache_enable)
);
}
static int __init nocache_trampoline(unsigned long __unused)
{
phys_reset_t phys_reset;
setup_mm_for_reboot();
sunxi_cluster_cache_disable_without_axi();
phys_reset = (phys_reset_t)(unsigned long)__pa_symbol(cpu_reset);
phys_reset(__pa_symbol(sunxi_mc_smp_resume), false);
BUG();
}
static int __init sunxi_mc_smp_lookback(void)
{
int ret;
/*
* We're going to soft-restart the current CPU through the
* low-level MCPM code by leveraging the suspend/resume
* infrastructure. Let's play it safe by using cpu_pm_enter()
* in case the CPU init code path resets the VFP or similar.
*/
sunxi_mc_smp_first_comer = true;
local_irq_disable();
local_fiq_disable();
ret = cpu_pm_enter();
if (!ret) {
ret = cpu_suspend(0, nocache_trampoline);
cpu_pm_exit();
}
local_fiq_enable();
local_irq_enable();
sunxi_mc_smp_first_comer = false;
return ret;
}
static int __init sunxi_mc_smp_init(void)
{
struct device_node *cpucfg_node, *node;
struct resource res;
int ret;
if (!of_machine_is_compatible("allwinner,sun9i-a80"))
return -ENODEV;
if (!sunxi_mc_smp_cpu_table_init())
return -EINVAL;
if (!cci_probed()) {
pr_err("%s: CCI-400 not available\n", __func__);
return -ENODEV;
}
node = of_find_compatible_node(NULL, NULL, "allwinner,sun9i-a80-prcm");
if (!node) {
pr_err("%s: PRCM not available\n", __func__);
return -ENODEV;
}
/*
* Unfortunately we can not request the I/O region for the PRCM.
* It is shared with the PRCM clock.
*/
prcm_base = of_iomap(node, 0);
of_node_put(node);
if (!prcm_base) {
pr_err("%s: failed to map PRCM registers\n", __func__);
return -ENOMEM;
}
cpucfg_node = of_find_compatible_node(NULL, NULL,
"allwinner,sun9i-a80-cpucfg");
if (!cpucfg_node) {
ret = -ENODEV;
pr_err("%s: CPUCFG not available\n", __func__);
goto err_unmap_prcm;
}
cpucfg_base = of_io_request_and_map(cpucfg_node, 0, "sunxi-mc-smp");
if (IS_ERR(cpucfg_base)) {
ret = PTR_ERR(cpucfg_base);
pr_err("%s: failed to map CPUCFG registers: %d\n",
__func__, ret);
goto err_put_cpucfg_node;
}
/* Configure CCI-400 for boot cluster */
ret = sunxi_mc_smp_lookback();
if (ret) {
pr_err("%s: failed to configure boot cluster: %d\n",
__func__, ret);
goto err_unmap_release_cpucfg;
}
/* We don't need the CPUCFG device node anymore */
of_node_put(cpucfg_node);
/* Set the hardware entry point address */
writel(__pa_symbol(sunxi_mc_smp_secondary_startup),
prcm_base + PRCM_CPU_SOFT_ENTRY_REG);
/* Actually enable multi cluster SMP */
smp_set_ops(&sunxi_mc_smp_smp_ops);
pr_info("sunxi multi cluster SMP support installed\n");
return 0;
err_unmap_release_cpucfg:
iounmap(cpucfg_base);
of_address_to_resource(cpucfg_node, 0, &res);
release_mem_region(res.start, resource_size(&res));
err_put_cpucfg_node:
of_node_put(cpucfg_node);
err_unmap_prcm:
iounmap(prcm_base);
return ret;
}
early_initcall(sunxi_mc_smp_init);