diff mbox

[V3] ARM: bcm281xx: Add timer driver

Message ID 1355250387-622-1-git-send-email-csd@broadcom.com (mailing list archive)
State New, archived
Headers show

Commit Message

Christian Daudt Dec. 11, 2012, 6:26 p.m. UTC
This adds support for the Broadcom timer, used in the following SoCs:
BCM11130, BCM11140, BCM11351, BCM28145, BCM28155

This patch needs the arm-soc/soc/next branch

Updates from V2:
 - prepend static fns + fields with kona_

Updates from V1:
 - Rename bcm_timer.c to bcm_kona_timer.c
 - Pull .h into bcm_kona_timer.c
 - Make timers static
 - Clean up comment block
 - Switched to using clockevents_config_and_register
 - Added an error to the get_timer loop if it repeats too much
 - Added to Documentation/devicetree/bindings/arm/bcm/bcm,kona-timer.txt
 - Added missing readl to timer_disable_and_clear

Note: bcm,kona-timer was kept as the 'compatible' field to make it
specific enough for when there are multiple bcm timers (bcm,timer is
too generic).

Signed-off-by: Christian Daudt <csd@broadcom.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: John Stultz <johnstul@us.ibm.com>

Comments

Stephen Warren Dec. 11, 2012, 7:02 p.m. UTC | #1
On 12/11/2012 11:26 AM, Christian Daudt wrote:
> This adds support for the Broadcom timer, used in the following SoCs:
> BCM11130, BCM11140, BCM11351, BCM28145, BCM28155

Reviewed-by: Stephen Warren <swarren@nvidia.com>

> This patch needs the arm-soc/soc/next branch

Only if it goes into 3.8, which I assume it won't?

For 3.9, you'll need to rebase it on top of my struct sys_timer removal
series, which I hope to put into linux-next ASAP after 3.8-rc1 comes out.
Christian Daudt Dec. 11, 2012, 7:13 p.m. UTC | #2
On 12-12-11 11:02 AM, Stephen Warren wrote:
> On 12/11/2012 11:26 AM, Christian Daudt wrote:
>> This adds support for the Broadcom timer, used in the following SoCs:
>> BCM11130, BCM11140, BCM11351, BCM28145, BCM28155
> Reviewed-by: Stephen Warren<swarren@nvidia.com>
>
Thanks.

>> This patch needs the arm-soc/soc/next branch
> Only if it goes into 3.8, which I assume it won't?
>
Ok, I wasn't clear on that. I meant that this patch only applies on top 
of arm-soc/soc/next as it needs the mach-bcm patch which is sitting only 
there at the moment. I'm fine with having this in 3.8 as this patch only 
affects the above SoCs. But I'll leave that to Olof and Arnd.
> For 3.9, you'll need to rebase it on top of my struct sys_timer removal
> series, which I hope to put into linux-next ASAP after 3.8-rc1 comes out.
>
Is there a git repo where I can look into this right now ? If so I can 
already look at what diffs will be required for this.

  Thanks,
    csd
Olof Johansson Dec. 11, 2012, 7:22 p.m. UTC | #3
On Tue, Dec 11, 2012 at 11:13 AM, Christian Daudt <csd@broadcom.com> wrote:
> On 12-12-11 11:02 AM, Stephen Warren wrote:
>>
>> On 12/11/2012 11:26 AM, Christian Daudt wrote:
>>>
>>> This adds support for the Broadcom timer, used in the following SoCs:
>>> BCM11130, BCM11140, BCM11351, BCM28145, BCM28155
>>
>> Reviewed-by: Stephen Warren<swarren@nvidia.com>
>>
> Thanks.
>
>
>>> This patch needs the arm-soc/soc/next branch
>>
>> Only if it goes into 3.8, which I assume it won't?
>>
> Ok, I wasn't clear on that. I meant that this patch only applies on top of
> arm-soc/soc/next as it needs the mach-bcm patch which is sitting only there
> at the moment. I'm fine with having this in 3.8 as this patch only affects
> the above SoCs. But I'll leave that to Olof and Arnd.

Let's aim for 3.9 at this time. Once we've merged all our stuff for
3.8, if there is time left, I might revisit this but by default 3.9 is
the appropriate target right now.



-Olof
Stephen Warren Dec. 11, 2012, 8:36 p.m. UTC | #4
On 12/11/2012 12:13 PM, Christian Daudt wrote:
> On 12-12-11 11:02 AM, Stephen Warren wrote:
>> On 12/11/2012 11:26 AM, Christian Daudt wrote:
>>> This adds support for the Broadcom timer, used in the following SoCs:
>>> BCM11130, BCM11140, BCM11351, BCM28145, BCM28155

>> For 3.9, you'll need to rebase it on top of my struct sys_timer removal
>> series, which I hope to put into linux-next ASAP after 3.8-rc1 comes out.
>
> Is there a git repo where I can look into this right now ? If so I can
> already look at what diffs will be required for this.

Sure, it's at:

git://nv-tegra.nvidia.com/user/swarren/linux-2.6 arm_timer_rework

Note that branch gets rebased, as I move it forward on to newer linux
next periodically. Once 3.8-rc1 comes out and I have a final stable
version, I'll arrange to get it into arm-soc, so it can be used as a
base for other people's patches.

Olof, Arnd, that brings me to the question of:

Should I:

a) Add that branch into linux-next (e.g. via the Tegra tree's for-next)
right after v3.8-rc1, let is sit there for a week or two (to allow
rebasing to squash in any fixes that show up as being needed), and then
send a pull request to arm-soc as a stable branch,

or:

b) Send a pull request to arm-soc right after 3.8-rc1, and let you do
any rebasing/squashing needed, before declaring it stable say around
3.8-rc2 or 3.8-rc3?
Arnd Bergmann Dec. 11, 2012, 10:38 p.m. UTC | #5
On Tuesday 11 December 2012, Stephen Warren wrote:
> Olof, Arnd, that brings me to the question of:
> 
> Should I:
> 
> a) Add that branch into linux-next (e.g. via the Tegra tree's for-next)
> right after v3.8-rc1, let is sit there for a week or two (to allow
> rebasing to squash in any fixes that show up as being needed), and then
> send a pull request to arm-soc as a stable branch,
> 
> or:
> 
> b) Send a pull request to arm-soc right after 3.8-rc1, and let you do
> any rebasing/squashing needed, before declaring it stable say around
> 3.8-rc2 or 3.8-rc3?

I think either way works fine. The first one is less work for us though ;-)

	Arnd
Olof Johansson Dec. 11, 2012, 10:42 p.m. UTC | #6
On Tue, Dec 11, 2012 at 2:38 PM, Arnd Bergmann <arnd@arndb.de> wrote:
> On Tuesday 11 December 2012, Stephen Warren wrote:
>> Olof, Arnd, that brings me to the question of:
>>
>> Should I:
>>
>> a) Add that branch into linux-next (e.g. via the Tegra tree's for-next)
>> right after v3.8-rc1, let is sit there for a week or two (to allow
>> rebasing to squash in any fixes that show up as being needed), and then
>> send a pull request to arm-soc as a stable branch,
>>
>> or:
>>
>> b) Send a pull request to arm-soc right after 3.8-rc1, and let you do
>> any rebasing/squashing needed, before declaring it stable say around
>> 3.8-rc2 or 3.8-rc3?
>
> I think either way works fine. The first one is less work for us though ;-)

Ah, looks like I hit "reply" instead of "reply all" earlier when I said:

We can pull it in as a non-stable branch that we can rebase if you
send us replacement branches, and then move it to a "stable" version
around rc2/3. I think that's probably easier than doing it all the way
"up" through linux-next for other subarch maintainers.

So, yeah, whatever will be easier for everyone.

-Olof
diff mbox

Patch

diff --git a/Documentation/devicetree/bindings/arm/bcm/bcm,kona-timer.txt b/Documentation/devicetree/bindings/arm/bcm/bcm,kona-timer.txt
new file mode 100644
index 0000000..59fa6e6
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/bcm/bcm,kona-timer.txt
@@ -0,0 +1,19 @@ 
+Broadcom Kona Family timer
+-----------------------------------------------------
+This timer is used in the following Broadcom SoCs:
+ BCM11130, BCM11140, BCM11351, BCM28145, BCM28155
+
+Required properties:
+- compatible : "bcm,kona-timer"
+- reg : Register range for the timer
+- interrupts : interrupt for the timer
+- clock-frequency: frequency that the clock operates
+
+Example:
+	timer@35006000 {
+		compatible = "bcm,kona-timer";
+		reg = <0x35006000 0x1000>;
+		interrupts = <0x0 7 0x4>;
+		clock-frequency = <32768>;
+	};
+
diff --git a/arch/arm/boot/dts/bcm11351.dtsi b/arch/arm/boot/dts/bcm11351.dtsi
index ad13588..8f71f40 100644
--- a/arch/arm/boot/dts/bcm11351.dtsi
+++ b/arch/arm/boot/dts/bcm11351.dtsi
@@ -47,4 +47,12 @@ 
 		    cache-unified;
 		    cache-level = <2>;
 	};
+
+	timer@35006000 {
+		compatible = "bcm,kona-timer";
+		reg = <0x35006000 0x1000>;
+		interrupts = <0x0 7 0x4>;
+		clock-frequency = <32768>;
+	};
+
 };
diff --git a/arch/arm/mach-bcm/board_bcm.c b/arch/arm/mach-bcm/board_bcm.c
index 3a62f1b..7929857 100644
--- a/arch/arm/mach-bcm/board_bcm.c
+++ b/arch/arm/mach-bcm/board_bcm.c
@@ -27,12 +27,10 @@  static const struct of_device_id irq_match[] = {
 	{}
 };
 
-static void timer_init(void)
-{
-}
+extern void kona_timer_init(void);
 
 static struct sys_timer timer = {
-	.init = timer_init,
+	.init = kona_timer_init,
 };
 
 static void __init init_irq(void)
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index 603be36..885afc5 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -14,5 +14,6 @@  obj-$(CONFIG_DW_APB_TIMER_OF)	+= dw_apb_timer_of.o
 obj-$(CONFIG_CLKSRC_DBX500_PRCMU)	+= clksrc-dbx500-prcmu.o
 obj-$(CONFIG_ARMADA_370_XP_TIMER)	+= time-armada-370-xp.o
 obj-$(CONFIG_ARCH_BCM2835)	+= bcm2835_timer.o
+obj-$(CONFIG_ARCH_BCM)		+= bcm_kona_timer.o
 
 obj-$(CONFIG_CLKSRC_ARM_GENERIC)	+= arm_generic.o
diff --git a/drivers/clocksource/bcm_kona_timer.c b/drivers/clocksource/bcm_kona_timer.c
new file mode 100644
index 0000000..c8803c5
--- /dev/null
+++ b/drivers/clocksource/bcm_kona_timer.c
@@ -0,0 +1,206 @@ 
+/*
+ * Copyright (C) 2012 Broadcom Corporation
+ *
+ * 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.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/jiffies.h>
+#include <linux/clockchips.h>
+#include <linux/types.h>
+
+#include <linux/io.h>
+#include <asm/mach/time.h>
+
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+
+
+#define KONA_GPTIMER_STCS_OFFSET			0x00000000
+#define KONA_GPTIMER_STCLO_OFFSET			0x00000004
+#define KONA_GPTIMER_STCHI_OFFSET			0x00000008
+#define KONA_GPTIMER_STCM0_OFFSET			0x0000000C
+
+#define KONA_GPTIMER_STCS_TIMER_MATCH_SHIFT		0
+#define KONA_GPTIMER_STCS_COMPARE_ENABLE_SHIFT		4
+
+struct kona_bcm_timers {
+	int tmr_irq;
+	void __iomem *tmr_regs;
+};
+
+static struct kona_bcm_timers timers;
+
+static u32 arch_timer_rate;
+
+/*
+ * We use the peripheral timers for system tick, the cpu global timer for
+ * profile tick
+ */
+static void kona_timer_disable_and_clear(void __iomem *base)
+{
+	uint32_t reg;
+
+	/*
+	 * clear and disable interrupts
+	 * We are using compare/match register 0 for our system interrupts
+	 */
+	reg = readl(base + KONA_GPTIMER_STCS_OFFSET);
+
+	/* Clear compare (0) interrupt */
+	reg |= 1 << KONA_GPTIMER_STCS_TIMER_MATCH_SHIFT;
+	/* disable compare */
+	reg &= ~(1 << KONA_GPTIMER_STCS_COMPARE_ENABLE_SHIFT);
+
+	writel(reg, base + KONA_GPTIMER_STCS_OFFSET);
+
+}
+
+static void
+kona_timer_get_counter(void *timer_base, uint32_t *msw, uint32_t *lsw)
+{
+	void __iomem *base = IOMEM(timer_base);
+	int loop_limit = 4;
+
+	/* Read 64-bit free running counter
+	 * 1. Read hi-word
+	 * 2. Read low-word
+	 * 3. Read hi-word again
+	 * 4.1
+	 *      if new hi-word is not equal to previously read hi-word, then
+	 *      start from #1
+	 * 4.2
+	 *      if new hi-word is equal to previously read hi-word then stop.
+	 */
+
+	while (--loop_limit) {
+		*msw = readl(base + KONA_GPTIMER_STCHI_OFFSET);
+		*lsw = readl(base + KONA_GPTIMER_STCLO_OFFSET);
+		if (*msw == readl(base + KONA_GPTIMER_STCHI_OFFSET))
+			break;
+	}
+	if (!loop_limit) {
+		pr_err("bcm_kona_timer: getting counter failed.\n");
+		pr_err(" Timer will be impacted\n");
+	}
+
+	return;
+}
+
+static const struct of_device_id bcm_timer_ids[] __initconst = {
+	{.compatible = "bcm,kona-timer"},
+	{},
+};
+
+static void __init kona_timers_init(void)
+{
+	struct device_node *node;
+	u32 freq;
+
+	node = of_find_matching_node(NULL, bcm_timer_ids);
+
+	if (!node)
+		panic("No timer");
+
+	if (!of_property_read_u32(node, "clock-frequency", &freq))
+		arch_timer_rate = freq;
+	else
+		panic("clock-frequency not set in the .dts file");
+
+	/* Setup IRQ numbers */
+	timers.tmr_irq = irq_of_parse_and_map(node, 0);
+
+	/* Setup IO addresses */
+	timers.tmr_regs = of_iomap(node, 0);
+
+	kona_timer_disable_and_clear(timers.tmr_regs);
+}
+
+static int kona_timer_set_next_event(unsigned long clc,
+				  struct clock_event_device *unused)
+{
+	/* timer (0) is disabled by the timer interrupt already
+	 * so, here we reload the next event value and re-enable
+	 * the timer
+	 *
+	 * This way, we are potentially losing the time between
+	 * timer-interrupt->set_next_event. CPU local timers, when
+	 * they come in should get rid of skew
+	 */
+
+	uint32_t lsw, msw;
+	uint32_t reg;
+
+	kona_timer_get_counter(timers.tmr_regs, &msw, &lsw);
+
+	/* Load the "next" event tick value */
+	writel(lsw + clc, timers.tmr_regs + KONA_GPTIMER_STCM0_OFFSET);
+
+	/* Enable compare */
+	reg = readl(timers.tmr_regs + KONA_GPTIMER_STCS_OFFSET);
+	reg |= (1 << KONA_GPTIMER_STCS_COMPARE_ENABLE_SHIFT);
+	writel(reg, timers.tmr_regs + KONA_GPTIMER_STCS_OFFSET);
+
+	return 0;
+}
+
+static void kona_timer_set_mode(enum clock_event_mode mode,
+			     struct clock_event_device *unused)
+{
+	switch (mode) {
+	case CLOCK_EVT_MODE_ONESHOT:
+		/* by default mode is one shot don't do any thing */
+		break;
+	case CLOCK_EVT_MODE_UNUSED:
+	case CLOCK_EVT_MODE_SHUTDOWN:
+	default:
+		kona_timer_disable_and_clear(timers.tmr_regs);
+	}
+}
+
+static struct clock_event_device kona_clockevent_timer = {
+	.name = "timer 1",
+	.features = CLOCK_EVT_FEAT_ONESHOT,
+	.set_next_event = kona_timer_set_next_event,
+	.set_mode = kona_timer_set_mode
+};
+
+static void __init kona_timer_clockevents_init(void)
+{
+	kona_clockevent_timer.cpumask = cpumask_of(0);
+	clockevents_config_and_register(&kona_clockevent_timer,
+		arch_timer_rate, 6, 0xffffffff);
+}
+
+static irqreturn_t kona_timer_interrupt(int irq, void *dev_id)
+{
+	struct clock_event_device *evt = &kona_clockevent_timer;
+
+	kona_timer_disable_and_clear(timers.tmr_regs);
+	evt->event_handler(evt);
+	return IRQ_HANDLED;
+}
+
+static struct irqaction kona_timer_irq = {
+	.name = "Kona Timer Tick",
+	.flags = IRQF_TIMER,
+	.handler = kona_timer_interrupt,
+};
+
+void __init kona_timer_init(void)
+{
+	kona_timers_init();
+	kona_timer_clockevents_init();
+	setup_irq(timers.tmr_irq, &kona_timer_irq);
+	kona_timer_set_next_event((arch_timer_rate / HZ), NULL);
+}