[PATCH v6 03/11] soc: renesas: rcar-sysc: Add DT support for SYSC PM domains

Geert Uytterhoeven
2016-04-20T12:02:38Z

Populate the SYSC PM domains from DT, based on the presence of a device
node for the System Controller. The actual power area hiearchy, and
features of specific areas are obtained from tables in the C code.

The SYSCIER and SYSCIMR register values are derived from the power areas
present, which will help to get rid of the hardcoded values in R-Car H1
and R-Car Gen2 platform code later.

Initialization is done from an early_initcall(), to make sure the PM
Domains are initialized before secondary CPU bringup.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
v6:
- Drop unneeded genpd->dev_ops.active_wakeup callback,
- Move call to pm_genpd_init() after all local initialization,

v5:
- Mask SYSC interrupts sources before enabling them (doesn't matter
much as they're disabled at the GIC level anyway),
- Re-add explicit "always-on" power area instead of aliasing the SoC's
Clock Domain,
- Merge the two initialization phases again,

v4:
- Make sure not to clear reserved SYSCIMR bits that were set before,
- Make the always-on power area implicit and always present, and an
alias of the existing SoC's Clock Domain. This makes the number of
power areas a compile-time constant, and allows to drop PD_ALWAYS_ON
and some checks.
- Split initialization in two phases,
- Document that ARM cores are controlled by PSCI on R-Car Gen3
(although the underlying CPG/APMU hardware is the same as on Gen2),
- Minor improvements (double evaluation, unused parameter, debug
message consolidation),

v3:
- Drop check for CONFIG_PM_GENERIC_DOMAINS, which is now always
enabled on R-Car SoCs,
- Create PM Domains from hierarchy in C data instead of DT,
- Initialize SYSCIER early, as SYSC needs the interrupt sources to be
enabled to control power,
- Mask all SYSC interrupt sources for the CPU,
- Add support for an "always-on" domain,
- Use early_initcall() instead of core_initcall(),
- Do not power up CPU power areas during initialization, as this is
handled later (directly or indirectly) by the SMP code,

v2:
- Add missing definitions for SYSC_PWR_CA15_CPU and SYSC_PWR_CA7_CPU,
- Add R-Car H3 (r8a7795) support,
- Drop tests for CONFIG_ARCH_SHMOBILE_LEGACY,
- Add missing break statements in rcar_sysc_pwr_on_off(),
- Add missing calls to of_node_put() in error paths,
- Fix build if CONFIG_PM=n,
- Update compatible values,
- Update copyright.
---
drivers/soc/renesas/rcar-sysc.c | 202 +++++++++++++++++++++++++++++++++++++++-
drivers/soc/renesas/rcar-sysc.h | 53 +++++++++++
2 files changed, 254 insertions(+), 1 deletion(-)
create mode 100644 drivers/soc/renesas/rcar-sysc.h

diff --git a/drivers/soc/renesas/rcar-sysc.c b/drivers/soc/renesas/rcar-sysc.c
index 9ba5fd15c53bf9b9..95f2b59cbd76f777 100644
--- a/drivers/soc/renesas/rcar-sysc.c
+++ b/drivers/soc/renesas/rcar-sysc.c
@@ -2,6 +2,7 @@
* R-Car SYSC Power management support
*
* Copyright (C) 2014 Magnus Damm
+ * Copyright (C) 2015-2016 Glider bvba
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
@@ -11,10 +12,15 @@
#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 */
@@ -29,7 +35,8 @@
/*
* 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 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 */
@@ -48,6 +55,8 @@
#define SYSCISR_RETRIES 1000
#define SYSCISR_DELAY_US 1

+#define RCAR_PD_ALWAYS_ON 32 /* Always-on power area */
+
static void __iomem *rcar_sysc_base;
static DEFINE_SPINLOCK(rcar_sysc_lock); /* SMP CPUs + I/O devices */

@@ -162,3 +171,194 @@ void __iomem *rcar_sysc_init(phys_addr_t base)

return rcar_sysc_base;
}
+
+struct rcar_sysc_pd {
+ struct generic_pm_domain genpd;
+ struct rcar_sysc_ch ch;
+ unsigned int flags;
+ char name[0];
+};
+
+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);
+
+ if (pd->flags & PD_NO_CR) {
+ pr_debug("%s: Cannot control %s\n", __func__, genpd->name);
+ return -EBUSY;
+ }
+
+ if (pd->flags & PD_BUSY) {
+ pr_debug("%s: %s busy\n", __func__, genpd->name);
+ return -EBUSY;
+ }
+
+ return rcar_sysc_power_down(&pd->ch);
+}
+
+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);
+
+ if (pd->flags & PD_NO_CR) {
+ pr_debug("%s: Cannot control %s\n", __func__, genpd->name);
+ return 0;
+ }
+
+ return rcar_sysc_power_up(&pd->ch);
+}
+
+static void __init rcar_sysc_pd_setup(struct rcar_sysc_pd *pd)
+{
+ struct generic_pm_domain *genpd = &pd->genpd;
+ const char *name = pd->genpd.name;
+ struct dev_power_governor *gov = &simple_qos_governor;
+
+ 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");
+ pd->flags |= PD_BUSY;
+ gov = &pm_domain_always_on_gov;
+ } 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");
+ pd->flags |= PD_BUSY;
+ gov = &pm_domain_always_on_gov;
+ } else if (pd->flags & PD_NO_CR) {
+ /*
+ * This domain cannot be turned off.
+ */
+ pd->flags |= PD_BUSY;
+ gov = &pm_domain_always_on_gov;
+ }
+
+ 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_up(&pd->ch);
+
+finalize:
+ pm_genpd_init(genpd, gov, false);
+}
+
+static const struct of_device_id rcar_sysc_matches[] = {
+ { /* sentinel */ }
+};
+
+struct rcar_pm_domains {
+ struct genpd_onecell_data onecell_data;
+ struct generic_pm_domain *domains[RCAR_PD_ALWAYS_ON + 1];
+};
+
+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;
+ u32 syscier, syscimr;
+ 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;
+
+ base = of_iomap(np, 0);
+ if (!base) {
+ pr_warn("%s: Cannot map regs\n", np->full_name);
+ error = -ENOMEM;
+ goto out_put;
+ }
+
+ rcar_sysc_base = base;
+
+ 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);
+
+ for (i = 0, syscier = 0; i < info->num_areas; i++)
+ syscier |= BIT(info->areas[i].isr_bit);
+
+ /*
+ * Mask all interrupt sources to prevent the CPU from receiving them.
+ * Make sure not to clear reserved bits that were set before.
+ */
+ syscimr = ioread32(base + SYSCIMR);
+ syscimr |= syscier;
+ pr_debug("%s: syscimr = 0x%08x\n", np->full_name, syscimr);
+ iowrite32(syscimr, base + SYSCIMR);
+
+ /*
+ * SYSC needs all interrupt sources enabled to control power.
+ */
+ pr_debug("%s: syscier = 0x%08x\n", np->full_name, syscier);
+ iowrite32(syscier, base + SYSCIER);
+
+ for (i = 0; i < info->num_areas; i++) {
+ const struct rcar_sysc_area *area = &info->areas[i];
+ struct rcar_sysc_pd *pd;
+
+ 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;
+
+ rcar_sysc_pd_setup(pd);
+ if (area->parent >= 0)
+ pm_genpd_add_subdomain(domains->domains[area->parent],
+ &pd->genpd);
+
+ domains->domains[area->isr_bit] = &pd->genpd;
+ }
+
+ of_genpd_add_provider_onecell(np, &domains->onecell_data);
+
+out_put:
+ of_node_put(np);
+ return error;
+}
+early_initcall(rcar_sysc_pd_init);
diff --git a/drivers/soc/renesas/rcar-sysc.h b/drivers/soc/renesas/rcar-sysc.h
new file mode 100644
index 0000000000000000..7bb48b4f7334f960
--- /dev/null
+++ b/drivers/soc/renesas/rcar-sysc.h
@@ -0,0 +1,53 @@
+/*
+ * Renesas R-Car System Controller
+ *
+ * Copyright (C) 2016 Glider bvba
+ *
+ * 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 of the License.
+ */
+#ifndef __SOC_RENESAS_RCAR_SYSC_H__
+#define __SOC_RENESAS_RCAR_SYSC_H__
+
+#include <linux/types.h>
+
+
+/*
+ * Power Domain flags
+ */
+#define PD_CPU BIT(0) /* Area contains main CPU core */
+#define PD_SCU BIT(1) /* Area contains SCU and L2 cache */
+#define PD_NO_CR BIT(2) /* Area lacks PWR{ON,OFF}CR registers */
+
+#define PD_BUSY BIT(3) /* Busy, for internal use only */
+
+#define PD_CPU_CR PD_CPU /* CPU area has CR (R-Car H1) */
+#define PD_CPU_NOCR PD_CPU | PD_NO_CR /* CPU area lacks CR (R-Car Gen2/3) */
+#define PD_ALWAYS_ON PD_NO_CR /* Always-on area */
+
+
+/*
+ * Description of a Power Area
+ */
+
+struct rcar_sysc_area {
+ const char *name;
+ u16 chan_offs; /* Offset of PWRSR register for this area */
+ u8 chan_bit; /* Bit in PWR* (except for PWRUP in PWRSR) */
+ u8 isr_bit; /* Bit in SYSCI*R */
+ int parent; /* -1 if none */
+ unsigned int flags; /* See PD_* */
+};
+
+
+/*
+ * SoC-specific Power Area Description
+ */
+
+struct rcar_sysc_info {
+ const struct rcar_sysc_area *areas;
+ unsigned int num_areas;
+};
+
+#endif /* __SOC_RENESAS_RCAR_SYSC_H__ */
--
1.9.1