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linux_dsm_epyc7002/drivers/soc/renesas/rcar-sysc.c
Geert Uytterhoeven 44b5100f7b soc: renesas: rcar-sysc: Prepare for fixing power request conflicts 
Recent R-Car Gen3 SoCs added an External Request Mask Register to the
System Controller (SYSC).  This register allows to mask external power
requests for CPU or 3DG domains, to prevent conflicts between powering
off CPU cores or the 3D Graphics Engine, and changing the state of
another power domain through SYSC, which could lead to CPG state machine
lock-ups.

Add support for making use of this register.  Take into account that the
register is optional, and that its location and contents are
SoC-specific.

Note that the issue fixed by this cannot happen in the upstream kernel,
as upstream has no support for graphics acceleration yet.  SoCs lacking
the External Request Mask Register may need a different mitigation in
the future.

Inspired by a patch in the BSP by Dien Pham <dien.pham.ry@renesas.com>.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Link: https://lore.kernel.org/r/20190828113618.6672-2-geert+renesas@glider.be
2019-10-01 10:29:40 +02:00

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// SPDX-License-Identifier: GPL-2.0
/*
* R-Car SYSC Power management support
*
* Copyright (C) 2014 Magnus Damm
* Copyright (C) 2015-2017 Glider bvba
*/
#include <linux/clk/renesas.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/mm.h>
#include <linux/of_address.h>
#include <linux/pm_domain.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/io.h>
#include <linux/soc/renesas/rcar-sysc.h>
#include "rcar-sysc.h"
/* SYSC Common */
#define SYSCSR 0x00 /* SYSC Status Register */
#define SYSCISR 0x04 /* Interrupt Status Register */
#define SYSCISCR 0x08 /* Interrupt Status Clear Register */
#define SYSCIER 0x0c /* Interrupt Enable Register */
#define SYSCIMR 0x10 /* Interrupt Mask Register */
/* SYSC Status Register */
#define SYSCSR_PONENB 1 /* Ready for power resume requests */
#define SYSCSR_POFFENB 0 /* Ready for power shutoff requests */
/*
* Power Control Register Offsets inside the register block for each domain
* Note: The "CR" registers for ARM cores exist on H1 only
* Use WFI to power off, CPG/APMU to resume ARM cores on R-Car Gen2
* Use PSCI on R-Car Gen3
*/
#define PWRSR_OFFS 0x00 /* Power Status Register */
#define PWROFFCR_OFFS 0x04 /* Power Shutoff Control Register */
#define PWROFFSR_OFFS 0x08 /* Power Shutoff Status Register */
#define PWRONCR_OFFS 0x0c /* Power Resume Control Register */
#define PWRONSR_OFFS 0x10 /* Power Resume Status Register */
#define PWRER_OFFS 0x14 /* Power Shutoff/Resume Error */
#define SYSCSR_RETRIES 100
#define SYSCSR_DELAY_US 1
#define PWRER_RETRIES 100
#define PWRER_DELAY_US 1
#define SYSCISR_RETRIES 1000
#define SYSCISR_DELAY_US 1
#define RCAR_PD_ALWAYS_ON 32 /* Always-on power area */
struct rcar_sysc_ch {
u16 chan_offs;
u8 chan_bit;
u8 isr_bit;
};
static void __iomem *rcar_sysc_base;
static DEFINE_SPINLOCK(rcar_sysc_lock); /* SMP CPUs + I/O devices */
static u32 rcar_sysc_extmask_offs, rcar_sysc_extmask_val;
static int rcar_sysc_pwr_on_off(const struct rcar_sysc_ch *sysc_ch, bool on)
{
unsigned int sr_bit, reg_offs;
int k;
if (on) {
sr_bit = SYSCSR_PONENB;
reg_offs = PWRONCR_OFFS;
} else {
sr_bit = SYSCSR_POFFENB;
reg_offs = PWROFFCR_OFFS;
}
/* Wait until SYSC is ready to accept a power request */
for (k = 0; k < SYSCSR_RETRIES; k++) {
if (ioread32(rcar_sysc_base + SYSCSR) & BIT(sr_bit))
break;
udelay(SYSCSR_DELAY_US);
}
if (k == SYSCSR_RETRIES)
return -EAGAIN;
/* Submit power shutoff or power resume request */
iowrite32(BIT(sysc_ch->chan_bit),
rcar_sysc_base + sysc_ch->chan_offs + reg_offs);
return 0;
}
static int rcar_sysc_power(const struct rcar_sysc_ch *sysc_ch, bool on)
{
unsigned int isr_mask = BIT(sysc_ch->isr_bit);
unsigned int chan_mask = BIT(sysc_ch->chan_bit);
unsigned int status;
unsigned long flags;
int ret = 0;
int k;
spin_lock_irqsave(&rcar_sysc_lock, flags);
/*
* Mask external power requests for CPU or 3DG domains
*/
if (rcar_sysc_extmask_val) {
iowrite32(rcar_sysc_extmask_val,
rcar_sysc_base + rcar_sysc_extmask_offs);
}
/*
* The interrupt source needs to be enabled, but masked, to prevent the
* CPU from receiving it.
*/
iowrite32(ioread32(rcar_sysc_base + SYSCIMR) | isr_mask,
rcar_sysc_base + SYSCIMR);
iowrite32(ioread32(rcar_sysc_base + SYSCIER) | isr_mask,
rcar_sysc_base + SYSCIER);
iowrite32(isr_mask, rcar_sysc_base + SYSCISCR);
/* Submit power shutoff or resume request until it was accepted */
for (k = 0; k < PWRER_RETRIES; k++) {
ret = rcar_sysc_pwr_on_off(sysc_ch, on);
if (ret)
goto out;
status = ioread32(rcar_sysc_base +
sysc_ch->chan_offs + PWRER_OFFS);
if (!(status & chan_mask))
break;
udelay(PWRER_DELAY_US);
}
if (k == PWRER_RETRIES) {
ret = -EIO;
goto out;
}
/* Wait until the power shutoff or resume request has completed * */
for (k = 0; k < SYSCISR_RETRIES; k++) {
if (ioread32(rcar_sysc_base + SYSCISR) & isr_mask)
break;
udelay(SYSCISR_DELAY_US);
}
if (k == SYSCISR_RETRIES)
ret = -EIO;
iowrite32(isr_mask, rcar_sysc_base + SYSCISCR);
out:
if (rcar_sysc_extmask_val)
iowrite32(0, rcar_sysc_base + rcar_sysc_extmask_offs);
spin_unlock_irqrestore(&rcar_sysc_lock, flags);
pr_debug("sysc power %s domain %d: %08x -> %d\n", on ? "on" : "off",
sysc_ch->isr_bit, ioread32(rcar_sysc_base + SYSCISR), ret);
return ret;
}
static bool rcar_sysc_power_is_off(const struct rcar_sysc_ch *sysc_ch)
{
unsigned int st;
st = ioread32(rcar_sysc_base + sysc_ch->chan_offs + PWRSR_OFFS);
if (st & BIT(sysc_ch->chan_bit))
return true;
return false;
}
struct rcar_sysc_pd {
struct generic_pm_domain genpd;
struct rcar_sysc_ch ch;
unsigned int flags;
char name[];
};
static inline struct rcar_sysc_pd *to_rcar_pd(struct generic_pm_domain *d)
{
return container_of(d, struct rcar_sysc_pd, genpd);
}
static int rcar_sysc_pd_power_off(struct generic_pm_domain *genpd)
{
struct rcar_sysc_pd *pd = to_rcar_pd(genpd);
pr_debug("%s: %s\n", __func__, genpd->name);
return rcar_sysc_power(&pd->ch, false);
}
static int rcar_sysc_pd_power_on(struct generic_pm_domain *genpd)
{
struct rcar_sysc_pd *pd = to_rcar_pd(genpd);
pr_debug("%s: %s\n", __func__, genpd->name);
return rcar_sysc_power(&pd->ch, true);
}
static bool has_cpg_mstp;
static int __init rcar_sysc_pd_setup(struct rcar_sysc_pd *pd)
{
struct generic_pm_domain *genpd = &pd->genpd;
const char *name = pd->genpd.name;
int error;
if (pd->flags & PD_CPU) {
/*
* This domain contains a CPU core and therefore it should
* only be turned off if the CPU is not in use.
*/
pr_debug("PM domain %s contains %s\n", name, "CPU");
genpd->flags |= GENPD_FLAG_ALWAYS_ON;
} else if (pd->flags & PD_SCU) {
/*
* This domain contains an SCU and cache-controller, and
* therefore it should only be turned off if the CPU cores are
* not in use.
*/
pr_debug("PM domain %s contains %s\n", name, "SCU");
genpd->flags |= GENPD_FLAG_ALWAYS_ON;
} else if (pd->flags & PD_NO_CR) {
/*
* This domain cannot be turned off.
*/
genpd->flags |= GENPD_FLAG_ALWAYS_ON;
}
if (!(pd->flags & (PD_CPU | PD_SCU))) {
/* Enable Clock Domain for I/O devices */
genpd->flags |= GENPD_FLAG_PM_CLK | GENPD_FLAG_ACTIVE_WAKEUP;
if (has_cpg_mstp) {
genpd->attach_dev = cpg_mstp_attach_dev;
genpd->detach_dev = cpg_mstp_detach_dev;
} else {
genpd->attach_dev = cpg_mssr_attach_dev;
genpd->detach_dev = cpg_mssr_detach_dev;
}
}
genpd->power_off = rcar_sysc_pd_power_off;
genpd->power_on = rcar_sysc_pd_power_on;
if (pd->flags & (PD_CPU | PD_NO_CR)) {
/* Skip CPUs (handled by SMP code) and areas without control */
pr_debug("%s: Not touching %s\n", __func__, genpd->name);
goto finalize;
}
if (!rcar_sysc_power_is_off(&pd->ch)) {
pr_debug("%s: %s is already powered\n", __func__, genpd->name);
goto finalize;
}
rcar_sysc_power(&pd->ch, true);
finalize:
error = pm_genpd_init(genpd, &simple_qos_governor, false);
if (error)
pr_err("Failed to init PM domain %s: %d\n", name, error);
return error;
}
static const struct of_device_id rcar_sysc_matches[] __initconst = {
#ifdef CONFIG_SYSC_R8A7743
{ .compatible = "renesas,r8a7743-sysc", .data = &r8a7743_sysc_info },
/* RZ/G1N is identical to RZ/G2M w.r.t. power domains. */
{ .compatible = "renesas,r8a7744-sysc", .data = &r8a7743_sysc_info },
#endif
#ifdef CONFIG_SYSC_R8A7745
{ .compatible = "renesas,r8a7745-sysc", .data = &r8a7745_sysc_info },
#endif
#ifdef CONFIG_SYSC_R8A77470
{ .compatible = "renesas,r8a77470-sysc", .data = &r8a77470_sysc_info },
#endif
#ifdef CONFIG_SYSC_R8A774A1
{ .compatible = "renesas,r8a774a1-sysc", .data = &r8a774a1_sysc_info },
#endif
#ifdef CONFIG_SYSC_R8A774C0
{ .compatible = "renesas,r8a774c0-sysc", .data = &r8a774c0_sysc_info },
#endif
#ifdef CONFIG_SYSC_R8A7779
{ .compatible = "renesas,r8a7779-sysc", .data = &r8a7779_sysc_info },
#endif
#ifdef CONFIG_SYSC_R8A7790
{ .compatible = "renesas,r8a7790-sysc", .data = &r8a7790_sysc_info },
#endif
#ifdef CONFIG_SYSC_R8A7791
{ .compatible = "renesas,r8a7791-sysc", .data = &r8a7791_sysc_info },
/* R-Car M2-N is identical to R-Car M2-W w.r.t. power domains. */
{ .compatible = "renesas,r8a7793-sysc", .data = &r8a7791_sysc_info },
#endif
#ifdef CONFIG_SYSC_R8A7792
{ .compatible = "renesas,r8a7792-sysc", .data = &r8a7792_sysc_info },
#endif
#ifdef CONFIG_SYSC_R8A7794
{ .compatible = "renesas,r8a7794-sysc", .data = &r8a7794_sysc_info },
#endif
#ifdef CONFIG_SYSC_R8A7795
{ .compatible = "renesas,r8a7795-sysc", .data = &r8a7795_sysc_info },
#endif
#ifdef CONFIG_SYSC_R8A7796
{ .compatible = "renesas,r8a7796-sysc", .data = &r8a7796_sysc_info },
#endif
#ifdef CONFIG_SYSC_R8A77965
{ .compatible = "renesas,r8a77965-sysc", .data = &r8a77965_sysc_info },
#endif
#ifdef CONFIG_SYSC_R8A77970
{ .compatible = "renesas,r8a77970-sysc", .data = &r8a77970_sysc_info },
#endif
#ifdef CONFIG_SYSC_R8A77980
{ .compatible = "renesas,r8a77980-sysc", .data = &r8a77980_sysc_info },
#endif
#ifdef CONFIG_SYSC_R8A77990
{ .compatible = "renesas,r8a77990-sysc", .data = &r8a77990_sysc_info },
#endif
#ifdef CONFIG_SYSC_R8A77995
{ .compatible = "renesas,r8a77995-sysc", .data = &r8a77995_sysc_info },
#endif
{ /* sentinel */ }
};
struct rcar_pm_domains {
struct genpd_onecell_data onecell_data;
struct generic_pm_domain *domains[RCAR_PD_ALWAYS_ON + 1];
};
static struct genpd_onecell_data *rcar_sysc_onecell_data;
static int __init rcar_sysc_pd_init(void)
{
const struct rcar_sysc_info *info;
const struct of_device_id *match;
struct rcar_pm_domains *domains;
struct device_node *np;
void __iomem *base;
unsigned int i;
int error;
np = of_find_matching_node_and_match(NULL, rcar_sysc_matches, &match);
if (!np)
return -ENODEV;
info = match->data;
if (info->init) {
error = info->init();
if (error)
goto out_put;
}
has_cpg_mstp = of_find_compatible_node(NULL, NULL,
"renesas,cpg-mstp-clocks");
base = of_iomap(np, 0);
if (!base) {
pr_warn("%pOF: Cannot map regs\n", np);
error = -ENOMEM;
goto out_put;
}
rcar_sysc_base = base;
/* Optional External Request Mask Register */
rcar_sysc_extmask_offs = info->extmask_offs;
rcar_sysc_extmask_val = info->extmask_val;
domains = kzalloc(sizeof(*domains), GFP_KERNEL);
if (!domains) {
error = -ENOMEM;
goto out_put;
}
domains->onecell_data.domains = domains->domains;
domains->onecell_data.num_domains = ARRAY_SIZE(domains->domains);
rcar_sysc_onecell_data = &domains->onecell_data;
for (i = 0; i < info->num_areas; i++) {
const struct rcar_sysc_area *area = &info->areas[i];
struct rcar_sysc_pd *pd;
if (!area->name) {
/* Skip NULLified area */
continue;
}
pd = kzalloc(sizeof(*pd) + strlen(area->name) + 1, GFP_KERNEL);
if (!pd) {
error = -ENOMEM;
goto out_put;
}
strcpy(pd->name, area->name);
pd->genpd.name = pd->name;
pd->ch.chan_offs = area->chan_offs;
pd->ch.chan_bit = area->chan_bit;
pd->ch.isr_bit = area->isr_bit;
pd->flags = area->flags;
error = rcar_sysc_pd_setup(pd);
if (error)
goto out_put;
domains->domains[area->isr_bit] = &pd->genpd;
if (area->parent < 0)
continue;
error = pm_genpd_add_subdomain(domains->domains[area->parent],
&pd->genpd);
if (error) {
pr_warn("Failed to add PM subdomain %s to parent %u\n",
area->name, area->parent);
goto out_put;
}
}
error = of_genpd_add_provider_onecell(np, &domains->onecell_data);
out_put:
of_node_put(np);
return error;
}
early_initcall(rcar_sysc_pd_init);
void __init rcar_sysc_nullify(struct rcar_sysc_area *areas,
unsigned int num_areas, u8 id)
{
unsigned int i;
for (i = 0; i < num_areas; i++)
if (areas[i].isr_bit == id) {
areas[i].name = NULL;
return;
}
}
#ifdef CONFIG_ARCH_R8A7779
static int rcar_sysc_power_cpu(unsigned int idx, bool on)
{
struct generic_pm_domain *genpd;
struct rcar_sysc_pd *pd;
unsigned int i;
if (!rcar_sysc_onecell_data)
return -ENODEV;
for (i = 0; i < rcar_sysc_onecell_data->num_domains; i++) {
genpd = rcar_sysc_onecell_data->domains[i];
if (!genpd)
continue;
pd = to_rcar_pd(genpd);
if (!(pd->flags & PD_CPU) || pd->ch.chan_bit != idx)
continue;
return rcar_sysc_power(&pd->ch, on);
}
return -ENOENT;
}
int rcar_sysc_power_down_cpu(unsigned int cpu)
{
return rcar_sysc_power_cpu(cpu, false);
}
int rcar_sysc_power_up_cpu(unsigned int cpu)
{
return rcar_sysc_power_cpu(cpu, true);
}
#endif /* CONFIG_ARCH_R8A7779 */
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