[v4,1/2] watchdog: bcm281xx: Watchdog Driver

Message ID 1384888074-19696-2-git-send-email-markus.mayer@linaro.org
State New
Headers show

Commit Message

Markus Mayer Nov. 19, 2013, 7:07 p.m.
This commit adds support for the watchdog timer used on the BCM281xx
family of SoCs.

Signed-off-by: Markus Mayer <markus.mayer@linaro.org>
Reviewed-by: Matt Porter <matt.porter@linaro.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
---
 drivers/watchdog/Kconfig        |   22 +++
 drivers/watchdog/Makefile       |    1 +
 drivers/watchdog/bcm_kona_wdt.c |  365 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 388 insertions(+)
 create mode 100644 drivers/watchdog/bcm_kona_wdt.c

Comments

Markus Mayer Nov. 20, 2013, 4:12 p.m. | #1
On 19 November 2013 11:07, Markus Mayer <markus.mayer@linaro.org> wrote:
> This commit adds support for the watchdog timer used on the BCM281xx
> family of SoCs.
>
> Signed-off-by: Markus Mayer <markus.mayer@linaro.org>
> Reviewed-by: Matt Porter <matt.porter@linaro.org>
> Reviewed-by: Guenter Roeck <linux@roeck-us.net>
> ---
>  drivers/watchdog/Kconfig        |   22 +++
>  drivers/watchdog/Makefile       |    1 +
>  drivers/watchdog/bcm_kona_wdt.c |  365 +++++++++++++++++++++++++++++++++++++++
>  3 files changed, 388 insertions(+)
>  create mode 100644 drivers/watchdog/bcm_kona_wdt.c
>

[...]

> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index 6c5bb27..7c860ca 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -55,6 +55,7 @@ obj-$(CONFIG_IMX2_WDT) += imx2_wdt.o
>  obj-$(CONFIG_UX500_WATCHDOG) += ux500_wdt.o
>  obj-$(CONFIG_RETU_WATCHDOG) += retu_wdt.o
>  obj-$(CONFIG_BCM2835_WDT) += bcm2835_wdt.o
> +obj-$(CONFIG_BCM_KONA_WDT) += bcm_kona_wdt.o
>
>  # AVR32 Architecture
>  obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o

Just to let everyone know, due to the watchdog -> mainline merge a few
days ago, there's a trivial merge conflict now in the makefile. I'll
send out a re-based v5 of this patch once 3.13-rc1 has been tagged
(unless you would like a rebased-to-tip version before then).

Regards,
-Markus
Guenter Roeck Nov. 20, 2013, 4:27 p.m. | #2
On Wed, Nov 20, 2013 at 08:12:37AM -0800, Markus Mayer wrote:
> On 19 November 2013 11:07, Markus Mayer <markus.mayer@linaro.org> wrote:
> > This commit adds support for the watchdog timer used on the BCM281xx
> > family of SoCs.
> >
> > Signed-off-by: Markus Mayer <markus.mayer@linaro.org>
> > Reviewed-by: Matt Porter <matt.porter@linaro.org>
> > Reviewed-by: Guenter Roeck <linux@roeck-us.net>
> > ---
> >  drivers/watchdog/Kconfig        |   22 +++
> >  drivers/watchdog/Makefile       |    1 +
> >  drivers/watchdog/bcm_kona_wdt.c |  365 +++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 388 insertions(+)
> >  create mode 100644 drivers/watchdog/bcm_kona_wdt.c
> >
> 
> [...]
> 
> > diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> > index 6c5bb27..7c860ca 100644
> > --- a/drivers/watchdog/Makefile
> > +++ b/drivers/watchdog/Makefile
> > @@ -55,6 +55,7 @@ obj-$(CONFIG_IMX2_WDT) += imx2_wdt.o
> >  obj-$(CONFIG_UX500_WATCHDOG) += ux500_wdt.o
> >  obj-$(CONFIG_RETU_WATCHDOG) += retu_wdt.o
> >  obj-$(CONFIG_BCM2835_WDT) += bcm2835_wdt.o
> > +obj-$(CONFIG_BCM_KONA_WDT) += bcm_kona_wdt.o
> >
> >  # AVR32 Architecture
> >  obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
> 
> Just to let everyone know, due to the watchdog -> mainline merge a few
> days ago, there's a trivial merge conflict now in the makefile. I'll
> send out a re-based v5 of this patch once 3.13-rc1 has been tagged
> (unless you would like a rebased-to-tip version before then).
> 
Hi Markus,

Yes, I noticed when I merged it into my watchdog-next branch.

Reminds me ... v3 had a whitespace problem. I don't recall if you fixed
that in v4. If you didn't, that might be a better reason to send v5.
Take your patch and apply it with "git am" to find out.

Thanks,
Guenter
Markus Mayer Nov. 20, 2013, 6:24 p.m. | #3
> Hi Markus,
>
> Yes, I noticed when I merged it into my watchdog-next branch.
>
> Reminds me ... v3 had a whitespace problem. I don't recall if you fixed
> that in v4. If you didn't, that might be a better reason to send v5.

That's still there, unfortunately. Trailing space on the first
help-text line in Kconfig:
    Support for the watchdog timer on the following Broadcom BCM281xx

So, I'll generate v5 with that fixed. Do you prefer I also rebase it
right now to whatever current tip is to take care of the merge
conflict?

Thanks,
-Markus
Guenter Roeck Nov. 20, 2013, 6:40 p.m. | #4
On Wed, Nov 20, 2013 at 10:24:54AM -0800, Markus Mayer wrote:
> > Hi Markus,
> >
> > Yes, I noticed when I merged it into my watchdog-next branch.
> >
> > Reminds me ... v3 had a whitespace problem. I don't recall if you fixed
> > that in v4. If you didn't, that might be a better reason to send v5.
> 
> That's still there, unfortunately. Trailing space on the first
> help-text line in Kconfig:
>     Support for the watchdog timer on the following Broadcom BCM281xx
> 
> So, I'll generate v5 with that fixed. Do you prefer I also rebase it
> right now to whatever current tip is to take care of the merge
> conflict?
> 
I would suggest to wait for -rc1 and rebase to it before you send the new
version. After all, it won't make it into 3.13 anyway, so no need to hurry.

Thanks,
Guenter
Markus Mayer Nov. 20, 2013, 6:42 p.m. | #5
On 20 November 2013 10:40, Guenter Roeck <linux@roeck-us.net> wrote:
> On Wed, Nov 20, 2013 at 10:24:54AM -0800, Markus Mayer wrote:
>> > Hi Markus,
>> >
>> > Yes, I noticed when I merged it into my watchdog-next branch.
>> >
>> > Reminds me ... v3 had a whitespace problem. I don't recall if you fixed
>> > that in v4. If you didn't, that might be a better reason to send v5.
>>
>> That's still there, unfortunately. Trailing space on the first
>> help-text line in Kconfig:
>>     Support for the watchdog timer on the following Broadcom BCM281xx
>>
>> So, I'll generate v5 with that fixed. Do you prefer I also rebase it
>> right now to whatever current tip is to take care of the merge
>> conflict?
>>
> I would suggest to wait for -rc1 and rebase to it before you send the new
> version. After all, it won't make it into 3.13 anyway, so no need to hurry.

Sure thing. I'll do that.

Thanks,
-Markus

Patch

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index d1d53f3..fe8bd21 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -1121,6 +1121,28 @@  config BCM2835_WDT
 	  To compile this driver as a loadable module, choose M here.
 	  The module will be called bcm2835_wdt.
 
+config BCM_KONA_WDT
+	tristate "BCM Kona Watchdog"
+	depends on ARCH_BCM
+	select WATCHDOG_CORE
+	help
+	  Support for the watchdog timer on the following Broadcom BCM281xx 
+	  family, which includes BCM11130, BCM11140, BCM11351, BCM28145 and
+	  BCM28155 variants.
+
+	  Say 'Y' or 'M' here to enable the driver. The module will be called
+	  bcm_kona_wdt.
+
+config BCM_KONA_WDT_DEBUG
+	bool "DEBUGFS support for BCM Kona Watchdog"
+	depends on BCM_KONA_WDT
+	help
+	  If enabled, adds /sys/kernel/debug/bcm-kona-wdt/info which provides
+	  access to the driver's internal data structures as well as watchdog
+	  timer hardware registres.
+
+	  If in doubt, say 'N'.
+
 config LANTIQ_WDT
 	tristate "Lantiq SoC watchdog"
 	depends on LANTIQ
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 6c5bb27..7c860ca 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -55,6 +55,7 @@  obj-$(CONFIG_IMX2_WDT) += imx2_wdt.o
 obj-$(CONFIG_UX500_WATCHDOG) += ux500_wdt.o
 obj-$(CONFIG_RETU_WATCHDOG) += retu_wdt.o
 obj-$(CONFIG_BCM2835_WDT) += bcm2835_wdt.o
+obj-$(CONFIG_BCM_KONA_WDT) += bcm_kona_wdt.o
 
 # AVR32 Architecture
 obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
diff --git a/drivers/watchdog/bcm_kona_wdt.c b/drivers/watchdog/bcm_kona_wdt.c
new file mode 100644
index 0000000..9fe174b
--- /dev/null
+++ b/drivers/watchdog/bcm_kona_wdt.c
@@ -0,0 +1,365 @@ 
+/*
+ * Copyright (C) 2013 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/debugfs.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+
+#define SECWDOG_CTRL_REG		0x00000000
+#define SECWDOG_COUNT_REG		0x00000004
+
+#define SECWDOG_RESERVED_MASK		0x1dffffff
+#define SECWDOG_WD_LOAD_FLAG		0x10000000
+#define SECWDOG_EN_MASK			0x08000000
+#define SECWDOG_SRSTEN_MASK		0x04000000
+#define SECWDOG_RES_MASK		0x00f00000
+#define SECWDOG_COUNT_MASK		0x000fffff
+
+#define SECWDOG_MAX_COUNT		SECWDOG_COUNT_MASK
+#define SECWDOG_CLKS_SHIFT		20
+#define SECWDOG_MAX_RES			15
+#define SECWDOG_DEFAULT_RESOLUTION	4
+#define SECWDOG_MAX_TRY			1000
+
+#define SECS_TO_TICKS(x, w)		((x) << (w)->resolution)
+#define TICKS_TO_SECS(x, w)		((x) >> (w)->resolution)
+
+#define BCM_KONA_WDT_NAME		"bcm_kona_wdt"
+
+struct bcm_kona_wdt {
+	void __iomem *base;
+	/*
+	 * One watchdog tick is 1/(2^resolution) seconds. Resolution can take
+	 * the values 0-15, meaning one tick can be 1s to 30.52us. Our default
+	 * resolution of 4 means one tick is 62.5ms.
+	 *
+	 * The watchdog counter is 20 bits. Depending on resolution, the maximum
+	 * counter value of 0xfffff expires after about 12 days (resolution 0)
+	 * down to only 32s (resolution 15). The default resolution of 4 gives
+	 * us a maximum of about 18 hours and 12 minutes before the watchdog
+	 * times out.
+	 */
+	int resolution;
+	spinlock_t lock;
+#ifdef CONFIG_BCM_KONA_WDT_DEBUG
+	struct dentry *debugfs;
+#endif
+};
+
+#ifdef CONFIG_BCM_KONA_WDT_DEBUG
+static unsigned long busy_count;
+#endif
+
+static int secure_register_read(void __iomem *addr)
+{
+	uint32_t val;
+	unsigned count = 0;
+
+	/*
+	 * If the WD_LOAD_FLAG is set, the watchdog counter field is being
+	 * updated in hardware. Once the WD timer is updated in hardware, it
+	 * gets cleared.
+	 */
+	do {
+		if (unlikely(count > 1))
+			udelay(5);
+		val = readl_relaxed(addr);
+		count++;
+	} while ((val & SECWDOG_WD_LOAD_FLAG) && count < SECWDOG_MAX_TRY);
+
+#ifdef CONFIG_BCM_KONA_WDT_DEBUG
+	/* Remember the maximum number iterations due to WD_LOAD_FLAG */
+	if (count > busy_count)
+		busy_count = count;
+#endif
+
+	/* This is the only place we return a negative value. */
+	if (val & SECWDOG_WD_LOAD_FLAG)
+		return -ETIMEDOUT;
+
+	/* We always mask out reserved bits. */
+	val &= SECWDOG_RESERVED_MASK;
+
+	return val;
+}
+
+#ifdef CONFIG_BCM_KONA_WDT_DEBUG
+
+static int bcm_kona_wdt_dbg_show(struct seq_file *s, void *data)
+{
+	int ctl_val, cur_val, ret;
+	unsigned long flags;
+	struct bcm_kona_wdt *wdt = s->private;
+
+	if (!wdt)
+		return seq_puts(s, "No device pointer\n");
+
+	spin_lock_irqsave(&wdt->lock, flags);
+	ctl_val = secure_register_read(wdt->base + SECWDOG_CTRL_REG);
+	cur_val = secure_register_read(wdt->base + SECWDOG_COUNT_REG);
+	spin_unlock_irqrestore(&wdt->lock, flags);
+
+	if (ctl_val < 0 || cur_val < 0) {
+		ret = seq_puts(s, "Error accessing hardware\n");
+	} else {
+		int ctl, cur, ctl_sec, cur_sec, res;
+
+		ctl = ctl_val & SECWDOG_COUNT_MASK;
+		res = (ctl_val & SECWDOG_RES_MASK) >> SECWDOG_CLKS_SHIFT;
+		cur = cur_val & SECWDOG_COUNT_MASK;
+		ctl_sec = TICKS_TO_SECS(ctl, wdt);
+		cur_sec = TICKS_TO_SECS(cur, wdt);
+		ret = seq_printf(s, "Resolution: %d / %d\n"
+				"Control: %d s / %d (%#x) ticks\n"
+				"Current: %d s / %d (%#x) ticks\n"
+				"Busy count: %lu\n", res,
+				wdt->resolution, ctl_sec, ctl, ctl, cur_sec,
+				cur, cur, busy_count);
+	}
+
+	return ret;
+}
+
+static int bcm_kona_dbg_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, bcm_kona_wdt_dbg_show, inode->i_private);
+}
+
+static const struct file_operations bcm_kona_dbg_operations = {
+	.open		= bcm_kona_dbg_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static struct dentry *bcm_kona_wdt_debugfs_init(struct bcm_kona_wdt *wdt,
+	struct watchdog_device *wdd)
+{
+	struct dentry *dir;
+
+	dir = debugfs_create_dir(BCM_KONA_WDT_NAME, NULL);
+	if (IS_ERR_OR_NULL(dir))
+		return NULL;
+
+	if (debugfs_create_file("info", S_IFREG | S_IRUGO, dir, wdt,
+				&bcm_kona_dbg_operations))
+		return dir;
+
+	/* Clean up */
+	debugfs_remove_recursive(dir);
+	return NULL;
+}
+
+static void bcm_kona_debugfs_exit(struct dentry *dir)
+{
+	debugfs_remove_recursive(dir);
+}
+
+#endif /* CONFIG_BCM_KONA_WDT_DEBUG */
+
+static int bcm_kona_wdt_ctrl_reg_modify(struct bcm_kona_wdt *wdt,
+					unsigned mask, unsigned newval)
+{
+	int val;
+	unsigned long flags;
+	int ret = 0;
+
+	spin_lock_irqsave(&wdt->lock, flags);
+
+	val = secure_register_read(wdt->base + SECWDOG_CTRL_REG);
+	if (val < 0) {
+		ret = val;
+	} else {
+		val &= ~mask;
+		val |= newval;
+		writel_relaxed(val, wdt->base + SECWDOG_CTRL_REG);
+	}
+
+	spin_unlock_irqrestore(&wdt->lock, flags);
+
+	return ret;
+}
+
+static int bcm_kona_wdt_set_resolution_reg(struct bcm_kona_wdt *wdt)
+{
+	if (wdt->resolution > SECWDOG_MAX_RES)
+		return -EINVAL;
+
+	return bcm_kona_wdt_ctrl_reg_modify(wdt, SECWDOG_RES_MASK,
+					wdt->resolution << SECWDOG_CLKS_SHIFT);
+}
+
+static int bcm_kona_wdt_set_timeout_reg(struct watchdog_device *wdog,
+					unsigned watchdog_flags)
+{
+	struct bcm_kona_wdt *wdt = watchdog_get_drvdata(wdog);
+
+	return bcm_kona_wdt_ctrl_reg_modify(wdt, SECWDOG_COUNT_MASK,
+					SECS_TO_TICKS(wdog->timeout, wdt) |
+					watchdog_flags);
+}
+
+static int bcm_kona_wdt_set_timeout(struct watchdog_device *wdog,
+	unsigned int t)
+{
+	wdog->timeout = t;
+	return 0;
+}
+
+static unsigned int bcm_kona_wdt_get_timeleft(struct watchdog_device *wdog)
+{
+	struct bcm_kona_wdt *wdt = watchdog_get_drvdata(wdog);
+	int val;
+	unsigned long flags;
+
+	spin_lock_irqsave(&wdt->lock, flags);
+	val = secure_register_read(wdt->base + SECWDOG_COUNT_REG);
+	spin_unlock_irqrestore(&wdt->lock, flags);
+
+	if (val < 0)
+		return val;
+
+	return TICKS_TO_SECS(val & SECWDOG_COUNT_MASK, wdt);
+}
+
+static int bcm_kona_wdt_start(struct watchdog_device *wdog)
+{
+	return bcm_kona_wdt_set_timeout_reg(wdog,
+					SECWDOG_EN_MASK | SECWDOG_SRSTEN_MASK);
+}
+
+static int bcm_kona_wdt_stop(struct watchdog_device *wdog)
+{
+	struct bcm_kona_wdt *wdt = watchdog_get_drvdata(wdog);
+
+	return bcm_kona_wdt_ctrl_reg_modify(wdt, SECWDOG_EN_MASK |
+					    SECWDOG_SRSTEN_MASK, 0);
+}
+
+static struct watchdog_ops bcm_kona_wdt_ops = {
+	.owner =	THIS_MODULE,
+	.start =	bcm_kona_wdt_start,
+	.stop =		bcm_kona_wdt_stop,
+	.set_timeout =	bcm_kona_wdt_set_timeout,
+	.get_timeleft =	bcm_kona_wdt_get_timeleft,
+};
+
+static struct watchdog_info bcm_kona_wdt_info = {
+	.options =	WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
+			WDIOF_KEEPALIVEPING,
+	.identity =	"Broadcom Kona Watchdog Timer",
+};
+
+static struct watchdog_device bcm_kona_wdt_wdd = {
+	.info =		&bcm_kona_wdt_info,
+	.ops =		&bcm_kona_wdt_ops,
+	.min_timeout =	1,
+	.max_timeout =	SECWDOG_MAX_COUNT >> SECWDOG_DEFAULT_RESOLUTION,
+	.timeout =	SECWDOG_MAX_COUNT >> SECWDOG_DEFAULT_RESOLUTION,
+};
+
+static void bcm_kona_wdt_shutdown(struct platform_device *pdev)
+{
+	bcm_kona_wdt_stop(&bcm_kona_wdt_wdd);
+}
+
+static int bcm_kona_wdt_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct bcm_kona_wdt *wdt;
+	struct resource *res;
+	int ret;
+
+	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
+	if (!wdt)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	wdt->base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(wdt->base))
+		return -ENODEV;
+
+	wdt->resolution = SECWDOG_DEFAULT_RESOLUTION;
+	ret = bcm_kona_wdt_set_resolution_reg(wdt);
+	if (ret) {
+		dev_err(dev, "Failed to set resolution (error: %d)", ret);
+		return ret;
+	}
+
+	spin_lock_init(&wdt->lock);
+	platform_set_drvdata(pdev, wdt);
+	watchdog_set_drvdata(&bcm_kona_wdt_wdd, wdt);
+
+	ret = bcm_kona_wdt_set_timeout_reg(&bcm_kona_wdt_wdd, 0);
+	if (ret) {
+		dev_err(dev, "Failed set watchdog timeout");
+		return ret;
+	}
+
+	ret = watchdog_register_device(&bcm_kona_wdt_wdd);
+	if (ret) {
+		dev_err(dev, "Failed to register watchdog device");
+		return ret;
+	}
+
+#ifdef CONFIG_BCM_KONA_WDT_DEBUG
+	wdt->debugfs = bcm_kona_wdt_debugfs_init(wdt, &bcm_kona_wdt_wdd);
+#endif
+	dev_dbg(dev, "Broadcom Kona Watchdog Timer");
+
+	return 0;
+}
+
+static int bcm_kona_wdt_remove(struct platform_device *pdev)
+{
+#ifdef CONFIG_BCM_KONA_WDT_DEBUG
+	struct bcm_kona_wdt *wdt = platform_get_drvdata(pdev);
+
+	if (wdt->debugfs)
+		bcm_kona_debugfs_exit(wdt->debugfs);
+#endif /* CONFIG_BCM_KONA_WDT_DEBUG */
+	bcm_kona_wdt_shutdown(pdev);
+	watchdog_unregister_device(&bcm_kona_wdt_wdd);
+	dev_dbg(&pdev->dev, "Watchdog driver disabled");
+
+	return 0;
+}
+
+static const struct of_device_id bcm_kona_wdt_of_match[] = {
+	{ .compatible = "brcm,kona-wdt", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, bcm_kona_wdt_of_match);
+
+static struct platform_driver bcm_kona_wdt_driver = {
+	.driver = {
+			.name = BCM_KONA_WDT_NAME,
+			.owner = THIS_MODULE,
+			.of_match_table = bcm_kona_wdt_of_match,
+		  },
+	.probe = bcm_kona_wdt_probe,
+	.remove = bcm_kona_wdt_remove,
+	.shutdown = bcm_kona_wdt_shutdown,
+};
+
+module_platform_driver(bcm_kona_wdt_driver);
+
+MODULE_ALIAS("platform:" BCM_KONA_WDT_NAME);
+MODULE_AUTHOR("Markus Mayer <mmayer@broadcom.com>");
+MODULE_DESCRIPTION("Broadcom Kona Watchdog Driver");
+MODULE_LICENSE("GPL v2");