From: Ezequiel Garcia <[email protected]>
The Pistachio SoC provides four general purpose timers, and allow
to implement a clocksource driver.
This driver can be used as a replacement for the MIPS GIC and MIPS R4K
clocksources and sched clocks, which are clocked from the CPU clock.
Given the general purpose timers are clocked from an independent clock,
this new clocksource driver will be useful to introduce CPUFreq support
for Pistachio machines.
Signed-off-by: Ezequiel Garcia <[email protected]>
Signed-off-by: Govindraj Raja <[email protected]>
---
changes from v4
----------------
Fixes comments from Daniel as dicussed in below thread:
http://patchwork.linux-mips.org/patch/10784/
drivers/clocksource/Kconfig | 5 +
drivers/clocksource/Makefile | 1 +
drivers/clocksource/time-pistachio.c | 216 +++++++++++++++++++++++++++++++++++
3 files changed, 222 insertions(+)
create mode 100644 drivers/clocksource/time-pistachio.c
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 4e57730..e642825 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -111,6 +111,11 @@ config CLKSRC_LPC32XX
select CLKSRC_MMIO
select CLKSRC_OF
+config CLKSRC_PISTACHIO
+ bool
+ default y if MACH_PISTACHIO
+ select CLKSRC_OF
+
config CLKSRC_STM32
bool "Clocksource for STM32 SoCs" if !ARCH_STM32
depends on OF && ARM && (ARCH_STM32 || COMPILE_TEST)
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index f228354..066337e 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -44,6 +44,7 @@ obj-$(CONFIG_FSL_FTM_TIMER) += fsl_ftm_timer.o
obj-$(CONFIG_VF_PIT_TIMER) += vf_pit_timer.o
obj-$(CONFIG_CLKSRC_QCOM) += qcom-timer.o
obj-$(CONFIG_MTK_TIMER) += mtk_timer.o
+obj-$(CONFIG_CLKSRC_PISTACHIO) += time-pistachio.o
obj-$(CONFIG_ARM_ARCH_TIMER) += arm_arch_timer.o
obj-$(CONFIG_ARM_GLOBAL_TIMER) += arm_global_timer.o
diff --git a/drivers/clocksource/time-pistachio.c b/drivers/clocksource/time-pistachio.c
new file mode 100644
index 0000000..a2e3c5d
--- /dev/null
+++ b/drivers/clocksource/time-pistachio.c
@@ -0,0 +1,216 @@
+/*
+ * Pistachio clocksource based on general-purpose timers
+ *
+ * Copyright (C) 2015 Imagination Technologies
+ *
+ * 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
+ * for more details.
+ */
+
+#define pr_fmt(fmt) "%s: " fmt, __func__
+
+#include <linux/clk.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/sched_clock.h>
+#include <linux/time.h>
+
+/* Top level reg */
+#define CR_TIMER_CTRL_CFG 0x00
+#define TIMER_ME_GLOBAL BIT(0)
+#define CR_TIMER_REV 0x10
+
+/* Timer specific registers */
+#define TIMER_CFG 0x20
+#define TIMER_ME_LOCAL BIT(0)
+#define TIMER_RELOAD_VALUE 0x24
+#define TIMER_CURRENT_VALUE 0x28
+#define TIMER_CURRENT_OVERFLOW_VALUE 0x2C
+#define TIMER_IRQ_STATUS 0x30
+#define TIMER_IRQ_CLEAR 0x34
+#define TIMER_IRQ_MASK 0x38
+
+#define PERIP_TIMER_CONTROL 0x90
+
+/* Timer specific configuration Values */
+#define RELOAD_VALUE 0xffffffff
+
+struct pistachio_clocksource {
+ void __iomem *base;
+ raw_spinlock_t lock;
+ struct clocksource cs;
+};
+
+struct pistachio_clocksource pcs_gpt;
+
+#define to_pistachio_clocksource(cs) \
+ container_of(cs, struct pistachio_clocksource, cs)
+
+static inline u32 gpt_readl(void __iomem *base, u32 offset, u32 gpt_id)
+{
+ return readl(base + 0x20 * gpt_id + offset);
+}
+
+static inline void gpt_writel(void __iomem *base, u32 value, u32 offset,
+ u32 gpt_id)
+{
+ writel(value, base + 0x20 * gpt_id + offset);
+}
+
+static cycle_t pistachio_clocksource_read_cycles(struct clocksource *cs)
+{
+ struct pistachio_clocksource *pcs = to_pistachio_clocksource(cs);
+ u32 counter, overflw;
+ unsigned long flags;
+
+ /* The counter value is only refreshed after the overflow value is read.
+ * And they must be read in strict order, hence raw spin lock added.
+ */
+
+ raw_spin_lock_irqsave(&pcs->lock, flags);
+ overflw = gpt_readl(pcs->base, TIMER_CURRENT_OVERFLOW_VALUE, 0);
+ counter = gpt_readl(pcs->base, TIMER_CURRENT_VALUE, 0);
+ raw_spin_unlock_irqrestore(&pcs->lock, flags);
+
+ return ~(cycle_t)counter;
+}
+
+static u64 notrace pistachio_read_sched_clock(void)
+{
+ return pistachio_clocksource_read_cycles(&pcs_gpt.cs);
+}
+
+static void pistachio_clksrc_set_mode(struct clocksource *cs, int timeridx,
+ int enable)
+{
+ struct pistachio_clocksource *pcs = to_pistachio_clocksource(cs);
+ u32 val;
+
+ val = gpt_readl(pcs->base, TIMER_CFG, timeridx);
+ if (enable)
+ val |= TIMER_ME_LOCAL;
+ else
+ val &= ~TIMER_ME_LOCAL;
+
+ gpt_writel(pcs->base, val, TIMER_CFG, timeridx);
+}
+
+static void pistachio_clksrc_enable(struct clocksource *cs, int timeridx)
+{
+ struct pistachio_clocksource *pcs = to_pistachio_clocksource(cs);
+
+ /* Disable GPT local before loading reload value */
+ pistachio_clksrc_set_mode(cs, timeridx, false);
+ gpt_writel(pcs->base, RELOAD_VALUE, TIMER_RELOAD_VALUE, timeridx);
+ pistachio_clksrc_set_mode(cs, timeridx, true);
+}
+
+static void pistachio_clksrc_disable(struct clocksource *cs, int timeridx)
+{
+ /* Disable GPT local */
+ pistachio_clksrc_set_mode(cs, timeridx, false);
+}
+
+static int pistachio_clocksource_enable(struct clocksource *cs)
+{
+ pistachio_clksrc_enable(cs, 0);
+ return 0;
+}
+
+static void pistachio_clocksource_disable(struct clocksource *cs)
+{
+ pistachio_clksrc_disable(cs, 0);
+}
+
+/* Desirable clock source for pistachio platform */
+struct pistachio_clocksource pcs_gpt = {
+ .cs = {
+ .name = "gptimer",
+ .rating = 300,
+ .enable = pistachio_clocksource_enable,
+ .disable = pistachio_clocksource_disable,
+ .read = pistachio_clocksource_read_cycles,
+ .mask = CLOCKSOURCE_MASK(32),
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS |
+ CLOCK_SOURCE_SUSPEND_NONSTOP,
+ },
+};
+
+static void __init pistachio_clksrc_of_init(struct device_node *node)
+{
+ struct clk *sys_clk, *fast_clk;
+ struct regmap *periph_regs;
+ unsigned long rate;
+ int ret;
+
+ pcs_gpt.base = of_iomap(node, 0);
+ if (!pcs_gpt.base) {
+ pr_err("cannot iomap\n");
+ return;
+ }
+
+ periph_regs = syscon_regmap_lookup_by_phandle(node, "img,cr-periph");
+ if (IS_ERR(periph_regs)) {
+ pr_err("cannot get peripheral regmap (%lu)\n",
+ PTR_ERR(periph_regs));
+ return;
+ }
+
+ /* Switch to using the fast counter clock */
+ ret = regmap_update_bits(periph_regs, PERIP_TIMER_CONTROL,
+ 0xf, 0x0);
+ if (ret)
+ return;
+
+ sys_clk = of_clk_get_by_name(node, "sys");
+ if (IS_ERR(sys_clk)) {
+ pr_err("clock get failed (%lu)\n", PTR_ERR(sys_clk));
+ return;
+ }
+
+ fast_clk = of_clk_get_by_name(node, "fast");
+ if (IS_ERR(fast_clk)) {
+ pr_err("clock get failed (%lu)\n", PTR_ERR(fast_clk));
+ return;
+ }
+
+ ret = clk_prepare_enable(sys_clk);
+ if (ret < 0) {
+ pr_err("failed to enable clock (%d)\n", ret);
+ return;
+ }
+
+ ret = clk_prepare_enable(fast_clk);
+ if (ret < 0) {
+ pr_err("failed to enable clock (%d)\n", ret);
+ clk_disable_unprepare(sys_clk);
+ return;
+ }
+
+ rate = clk_get_rate(fast_clk);
+
+ /* Disable irq's for clocksource usage */
+ gpt_writel(&pcs_gpt.base, 0, TIMER_IRQ_MASK, 0);
+ gpt_writel(&pcs_gpt.base, 0, TIMER_IRQ_MASK, 1);
+ gpt_writel(&pcs_gpt.base, 0, TIMER_IRQ_MASK, 2);
+ gpt_writel(&pcs_gpt.base, 0, TIMER_IRQ_MASK, 3);
+
+ /* Enable timer block */
+ writel(TIMER_ME_GLOBAL, pcs_gpt.base);
+
+ raw_spin_lock_init(&pcs_gpt.lock);
+ sched_clock_register(pistachio_read_sched_clock, 32, rate);
+ clocksource_register_hz(&pcs_gpt.cs, rate);
+}
+CLOCKSOURCE_OF_DECLARE(pistachio_gptimer, "img,pistachio-gptimer",
+ pistachio_clksrc_of_init);
--
1.9.1
On 08/06/2015 01:22 PM, Govindraj Raja wrote:
> From: Ezequiel Garcia <[email protected]>
>
> The Pistachio SoC provides four general purpose timers, and allow
> to implement a clocksource driver.
>
> This driver can be used as a replacement for the MIPS GIC and MIPS R4K
> clocksources and sched clocks, which are clocked from the CPU clock.
>
> Given the general purpose timers are clocked from an independent clock,
> this new clocksource driver will be useful to introduce CPUFreq support
> for Pistachio machines.
>
> Signed-off-by: Ezequiel Garcia <[email protected]>
> Signed-off-by: Govindraj Raja <[email protected]>
> ---
>
> changes from v4
> ----------------
> Fixes comments from Daniel as dicussed in below thread:
> http://patchwork.linux-mips.org/patch/10784/
>
>
> drivers/clocksource/Kconfig | 5 +
> drivers/clocksource/Makefile | 1 +
> drivers/clocksource/time-pistachio.c | 216 +++++++++++++++++++++++++++++++++++
> 3 files changed, 222 insertions(+)
> create mode 100644 drivers/clocksource/time-pistachio.c
>
> diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
[ ... ]
> index 4e57730..e642825 100644
> --- a/drivers/clocksource/Kconfig
> +++ b/drivers/clocksource/Kconfig
> @@ -111,6 +111,11 @@ config CLKSRC_LPC32XX
> select CLKSRC_MMIO
> select CLKSRC_OF
>
> +config CLKSRC_PISTACHIO
> + bool
> + default y if MACH_PISTACHIO
You don't need to add this condition.
> + select CLKSRC_OF
[ ... ]
> +
> +struct pistachio_clocksource pcs_gpt;
static.
> +#define to_pistachio_clocksource(cs) \
> + container_of(cs, struct pistachio_clocksource, cs)
> +
> +static inline u32 gpt_readl(void __iomem *base, u32 offset, u32 gpt_id)
> +{
> + return readl(base + 0x20 * gpt_id + offset);
Are you sure of the address computation ? I guess it is correct but just
wanted you to double check.
> +}
> +
> +static inline void gpt_writel(void __iomem *base, u32 value, u32 offset,
> + u32 gpt_id)
> +{
> + writel(value, base + 0x20 * gpt_id + offset);
> +}
> +
> +static cycle_t pistachio_clocksource_read_cycles(struct clocksource *cs)
> +{
> + struct pistachio_clocksource *pcs = to_pistachio_clocksource(cs);
> + u32 counter, overflw;
> + unsigned long flags;
> +
> + /* The counter value is only refreshed after the overflow value is read.
> + * And they must be read in strict order, hence raw spin lock added.
> + */
nit: extra carriage return and comment format:
/*
* blabla
*/
> + raw_spin_lock_irqsave(&pcs->lock, flags);
> + overflw = gpt_readl(pcs->base, TIMER_CURRENT_OVERFLOW_VALUE, 0);
> + counter = gpt_readl(pcs->base, TIMER_CURRENT_VALUE, 0);
> + raw_spin_unlock_irqrestore(&pcs->lock, flags);
> +
> + return ~(cycle_t)counter;
> +}
> +
> +static u64 notrace pistachio_read_sched_clock(void)
> +{
> + return pistachio_clocksource_read_cycles(&pcs_gpt.cs);
Can you double check the u32 cast to cycle_t returning a u64 from this
function ?
> +}
> +
> +static void pistachio_clksrc_set_mode(struct clocksource *cs, int timeridx,
> + int enable)
> +{
> + struct pistachio_clocksource *pcs = to_pistachio_clocksource(cs);
> + u32 val;
> +
> + val = gpt_readl(pcs->base, TIMER_CFG, timeridx);
> + if (enable)
> + val |= TIMER_ME_LOCAL;
> + else
> + val &= ~TIMER_ME_LOCAL;
> +
> + gpt_writel(pcs->base, val, TIMER_CFG, timeridx);
> +}
> +
> +static void pistachio_clksrc_enable(struct clocksource *cs, int timeridx)
> +{
> + struct pistachio_clocksource *pcs = to_pistachio_clocksource(cs);
> +
> + /* Disable GPT local before loading reload value */
> + pistachio_clksrc_set_mode(cs, timeridx, false);
> + gpt_writel(pcs->base, RELOAD_VALUE, TIMER_RELOAD_VALUE, timeridx);
> + pistachio_clksrc_set_mode(cs, timeridx, true);
> +}
> +
> +static void pistachio_clksrc_disable(struct clocksource *cs, int timeridx)
> +{
> + /* Disable GPT local */
> + pistachio_clksrc_set_mode(cs, timeridx, false);
> +}
> +
> +static int pistachio_clocksource_enable(struct clocksource *cs)
> +{
> + pistachio_clksrc_enable(cs, 0);
> + return 0;
> +}
> +
> +static void pistachio_clocksource_disable(struct clocksource *cs)
> +{
> + pistachio_clksrc_disable(cs, 0);
> +}
> +
> +/* Desirable clock source for pistachio platform */
> +struct pistachio_clocksource pcs_gpt = {
static.
Thanks !
-- Daniel
--
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Hi Daniel,
> -----Original Message-----
> From: Daniel Lezcano [mailto:[email protected]]
> Sent: 07 August 2015 11:28 AM
> To: Govindraj Raja; [email protected]; [email protected];
> [email protected]
> Cc: Thomas Gleixner; Andrew Bresticker; James Hartley; Damien Horsley; James
> Hogan; Ezequiel Garcia; Ezequiel Garcia
> Subject: Re: [PATCH v5 6/7] clocksource: Add Pistachio clocksource-only driver
>
> On 08/06/2015 01:22 PM, Govindraj Raja wrote:
> > From: Ezequiel Garcia <[email protected]>
> >
> > The Pistachio SoC provides four general purpose timers, and allow to
> > implement a clocksource driver.
> >
> > This driver can be used as a replacement for the MIPS GIC and MIPS R4K
> > clocksources and sched clocks, which are clocked from the CPU clock.
> >
> > Given the general purpose timers are clocked from an independent
> > clock, this new clocksource driver will be useful to introduce CPUFreq
> > support for Pistachio machines.
> >
> > Signed-off-by: Ezequiel Garcia <[email protected]>
> > Signed-off-by: Govindraj Raja <[email protected]>
> > ---
> >
> > changes from v4
> > ----------------
> > Fixes comments from Daniel as dicussed in below thread:
> > http://patchwork.linux-mips.org/patch/10784/
> >
> >
> > drivers/clocksource/Kconfig | 5 +
> > drivers/clocksource/Makefile | 1 +
> > drivers/clocksource/time-pistachio.c | 216
> +++++++++++++++++++++++++++++++++++
> > 3 files changed, 222 insertions(+)
> > create mode 100644 drivers/clocksource/time-pistachio.c
> >
> > diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
>
> [ ... ]
>
> > index 4e57730..e642825 100644
> > --- a/drivers/clocksource/Kconfig
> > +++ b/drivers/clocksource/Kconfig
> > @@ -111,6 +111,11 @@ config CLKSRC_LPC32XX
> > select CLKSRC_MMIO
> > select CLKSRC_OF
> >
> > +config CLKSRC_PISTACHIO
> > + bool
> > + default y if MACH_PISTACHIO
>
> You don't need to add this condition.
Ok fine. Will remove it.
>
> > + select CLKSRC_OF
>
> [ ... ]
>
> > +
> > +struct pistachio_clocksource pcs_gpt;
>
> static.
>
Ok.
> > +#define to_pistachio_clocksource(cs) \
> > + container_of(cs, struct pistachio_clocksource, cs)
> > +
> > +static inline u32 gpt_readl(void __iomem *base, u32 offset, u32
> > +gpt_id) {
> > + return readl(base + 0x20 * gpt_id + offset);
>
> Are you sure of the address computation ? I guess it is correct but just wanted
> you to double check.
>
Yes, tested it on Pistachio bring up board.
> > +}
> > +
> > +static inline void gpt_writel(void __iomem *base, u32 value, u32 offset,
> > + u32 gpt_id)
> > +{
> > + writel(value, base + 0x20 * gpt_id + offset); }
> > +
> > +static cycle_t pistachio_clocksource_read_cycles(struct clocksource
> > +*cs) {
> > + struct pistachio_clocksource *pcs = to_pistachio_clocksource(cs);
> > + u32 counter, overflw;
> > + unsigned long flags;
> > +
> > + /* The counter value is only refreshed after the overflow value is read.
> > + * And they must be read in strict order, hence raw spin lock added.
> > + */
>
> nit: extra carriage return and comment format:
>
> /*
> * blabla
> */
>
Ok.
> > + raw_spin_lock_irqsave(&pcs->lock, flags);
> > + overflw = gpt_readl(pcs->base, TIMER_CURRENT_OVERFLOW_VALUE,
> 0);
> > + counter = gpt_readl(pcs->base, TIMER_CURRENT_VALUE, 0);
> > + raw_spin_unlock_irqrestore(&pcs->lock, flags);
> > +
> > + return ~(cycle_t)counter;
> > +}
> > +
> > +static u64 notrace pistachio_read_sched_clock(void) {
> > + return pistachio_clocksource_read_cycles(&pcs_gpt.cs);
>
> Can you double check the u32 cast to cycle_t returning a u64 from this function ?
>
Sorry I didn't get you over this comment.
AFAIU,
from include/linux/types.h
[..]
/* clocksource cycle base type */
typedef u64 cycle_t;
[..]
Did you mean to check this?
> > +}
> > +
> > +static void pistachio_clksrc_set_mode(struct clocksource *cs, int timeridx,
> > + int enable)
> > +{
> > + struct pistachio_clocksource *pcs = to_pistachio_clocksource(cs);
> > + u32 val;
> > +
> > + val = gpt_readl(pcs->base, TIMER_CFG, timeridx);
> > + if (enable)
> > + val |= TIMER_ME_LOCAL;
> > + else
> > + val &= ~TIMER_ME_LOCAL;
> > +
> > + gpt_writel(pcs->base, val, TIMER_CFG, timeridx); }
> > +
> > +static void pistachio_clksrc_enable(struct clocksource *cs, int
> > +timeridx) {
> > + struct pistachio_clocksource *pcs = to_pistachio_clocksource(cs);
> > +
> > + /* Disable GPT local before loading reload value */
> > + pistachio_clksrc_set_mode(cs, timeridx, false);
> > + gpt_writel(pcs->base, RELOAD_VALUE, TIMER_RELOAD_VALUE,
> timeridx);
> > + pistachio_clksrc_set_mode(cs, timeridx, true); }
> > +
> > +static void pistachio_clksrc_disable(struct clocksource *cs, int
> > +timeridx) {
> > + /* Disable GPT local */
> > + pistachio_clksrc_set_mode(cs, timeridx, false); }
> > +
> > +static int pistachio_clocksource_enable(struct clocksource *cs) {
> > + pistachio_clksrc_enable(cs, 0);
> > + return 0;
> > +}
> > +
> > +static void pistachio_clocksource_disable(struct clocksource *cs) {
> > + pistachio_clksrc_disable(cs, 0);
> > +}
> > +
> > +/* Desirable clock source for pistachio platform */ struct
> > +pistachio_clocksource pcs_gpt = {
>
> static.
Ok.
Posting v6 addressing these comments.
--
Thanks.
Govindraj.R
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