From: Guenter Roeck <linux@roeck-us.net>
To: Tero Kristo <t-kristo@ti.com>,
wim@linux-watchdog.org, linux-watchdog@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, jan.kiszka@siemens.com
Subject: Re: [PATCHv4 3/4] watchdog: rti-wdt: attach to running watchdog during probe
Date: Sun, 19 Jul 2020 06:56:11 -0700 [thread overview]
Message-ID: <51c30a7c-a0e3-fc0b-2550-64749480a5fb@roeck-us.net> (raw)
In-Reply-To: <20200717132958.14304-4-t-kristo@ti.com>
On 7/17/20 6:29 AM, Tero Kristo wrote:
> If the RTI watchdog is running already during probe, the driver must
> configure itself to match the HW. Window size and timeout is probed from
> hardware, and the last keepalive ping is adjusted to match it also.
>
> Signed-off-by: Tero Kristo <t-kristo@ti.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
> ---
> drivers/watchdog/rti_wdt.c | 112 +++++++++++++++++++++++++++++++++----
> 1 file changed, 102 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/watchdog/rti_wdt.c b/drivers/watchdog/rti_wdt.c
> index d456dd72d99a..7cbdc178ffe8 100644
> --- a/drivers/watchdog/rti_wdt.c
> +++ b/drivers/watchdog/rti_wdt.c
> @@ -35,7 +35,11 @@
>
> #define RTIWWDRX_NMI 0xa
>
> -#define RTIWWDSIZE_50P 0x50
> +#define RTIWWDSIZE_50P 0x50
> +#define RTIWWDSIZE_25P 0x500
> +#define RTIWWDSIZE_12P5 0x5000
> +#define RTIWWDSIZE_6P25 0x50000
> +#define RTIWWDSIZE_3P125 0x500000
>
> #define WDENABLE_KEY 0xa98559da
>
> @@ -48,7 +52,7 @@
>
> #define DWDST BIT(1)
>
> -static int heartbeat;
> +static int heartbeat = DEFAULT_HEARTBEAT;
>
> /*
> * struct to hold data for each WDT device
> @@ -79,11 +83,9 @@ static int rti_wdt_start(struct watchdog_device *wdd)
> * be petted during the open window; not too early or not too late.
> * The HW configuration options only allow for the open window size
> * to be 50% or less than that; we obviouly want to configure the open
> - * window as large as possible so we select the 50% option. To avoid
> - * any glitches, we accommodate 5% safety margin also, so we setup
> - * the min_hw_hearbeat at 55% of the timeout period.
> + * window as large as possible so we select the 50% option.
> */
> - wdd->min_hw_heartbeat_ms = 11 * wdd->timeout * 1000 / 20;
> + wdd->min_hw_heartbeat_ms = 500 * wdd->timeout;
>
> /* Generate NMI when wdt expires */
> writel_relaxed(RTIWWDRX_NMI, wdt->base + RTIWWDRXCTRL);
> @@ -110,7 +112,48 @@ static int rti_wdt_ping(struct watchdog_device *wdd)
> return 0;
> }
>
> -static unsigned int rti_wdt_get_timeleft(struct watchdog_device *wdd)
> +static int rti_wdt_setup_hw_hb(struct watchdog_device *wdd, u32 wsize)
> +{
> + /*
> + * RTI only supports a windowed mode, where the watchdog can only
> + * be petted during the open window; not too early or not too late.
> + * The HW configuration options only allow for the open window size
> + * to be 50% or less than that.
> + */
> + switch (wsize) {
> + case RTIWWDSIZE_50P:
> + /* 50% open window => 50% min heartbeat */
> + wdd->min_hw_heartbeat_ms = 500 * heartbeat;
> + break;
> +
> + case RTIWWDSIZE_25P:
> + /* 25% open window => 75% min heartbeat */
> + wdd->min_hw_heartbeat_ms = 750 * heartbeat;
> + break;
> +
> + case RTIWWDSIZE_12P5:
> + /* 12.5% open window => 87.5% min heartbeat */
> + wdd->min_hw_heartbeat_ms = 875 * heartbeat;
> + break;
> +
> + case RTIWWDSIZE_6P25:
> + /* 6.5% open window => 93.5% min heartbeat */
> + wdd->min_hw_heartbeat_ms = 935 * heartbeat;
> + break;
> +
> + case RTIWWDSIZE_3P125:
> + /* 3.125% open window => 96.9% min heartbeat */
> + wdd->min_hw_heartbeat_ms = 969 * heartbeat;
> + break;
> +
> + default:
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> +static unsigned int rti_wdt_get_timeleft_ms(struct watchdog_device *wdd)
> {
> u64 timer_counter;
> u32 val;
> @@ -123,11 +166,18 @@ static unsigned int rti_wdt_get_timeleft(struct watchdog_device *wdd)
>
> timer_counter = readl_relaxed(wdt->base + RTIDWDCNTR);
>
> + timer_counter *= 1000;
> +
> do_div(timer_counter, wdt->freq);
>
> return timer_counter;
> }
>
> +static unsigned int rti_wdt_get_timeleft(struct watchdog_device *wdd)
> +{
> + return rti_wdt_get_timeleft_ms(wdd) / 1000;
> +}
> +
> static const struct watchdog_info rti_wdt_info = {
> .options = WDIOF_KEEPALIVEPING,
> .identity = "K3 RTI Watchdog",
> @@ -148,6 +198,7 @@ static int rti_wdt_probe(struct platform_device *pdev)
> struct watchdog_device *wdd;
> struct rti_wdt_device *wdt;
> struct clk *clk;
> + u32 last_ping = 0;
>
> wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
> if (!wdt)
> @@ -169,6 +220,14 @@ static int rti_wdt_probe(struct platform_device *pdev)
> return -EINVAL;
> }
>
> + /*
> + * If watchdog is running at 32k clock, it is not accurate.
> + * Adjust frequency down in this case so that we don't pet
> + * the watchdog too often.
> + */
> + if (wdt->freq < 32768)
> + wdt->freq = wdt->freq * 9 / 10;
> +
> pm_runtime_enable(dev);
> ret = pm_runtime_get_sync(dev);
> if (ret) {
> @@ -185,11 +244,8 @@ static int rti_wdt_probe(struct platform_device *pdev)
> wdd->min_timeout = 1;
> wdd->max_hw_heartbeat_ms = (WDT_PRELOAD_MAX << WDT_PRELOAD_SHIFT) /
> wdt->freq * 1000;
> - wdd->timeout = DEFAULT_HEARTBEAT;
> wdd->parent = dev;
>
> - watchdog_init_timeout(wdd, heartbeat, dev);
> -
> watchdog_set_drvdata(wdd, wdt);
> watchdog_set_nowayout(wdd, 1);
> watchdog_set_restart_priority(wdd, 128);
> @@ -201,12 +257,48 @@ static int rti_wdt_probe(struct platform_device *pdev)
> goto err_iomap;
> }
>
> + if (readl(wdt->base + RTIDWDCTRL) == WDENABLE_KEY) {
> + u32 time_left_ms;
> + u64 heartbeat_ms;
> + u32 wsize;
> +
> + set_bit(WDOG_HW_RUNNING, &wdd->status);
> + time_left_ms = rti_wdt_get_timeleft_ms(wdd);
> + heartbeat_ms = readl(wdt->base + RTIDWDPRLD);
> + heartbeat_ms <<= WDT_PRELOAD_SHIFT;
> + heartbeat_ms *= 1000;
> + do_div(heartbeat_ms, wdt->freq);
> + if (heartbeat_ms != heartbeat * 1000)
> + dev_warn(dev, "watchdog already running, ignoring heartbeat config!\n");
> +
> + heartbeat = heartbeat_ms;
> + heartbeat /= 1000;
> +
> + wsize = readl(wdt->base + RTIWWDSIZECTRL);
> + ret = rti_wdt_setup_hw_hb(wdd, wsize);
> + if (ret) {
> + dev_err(dev, "bad window size.\n");
> + goto err_iomap;
> + }
> +
> + last_ping = heartbeat_ms - time_left_ms;
> + if (time_left_ms > heartbeat_ms) {
> + dev_warn(dev, "time_left > heartbeat? Assuming last ping just before now.\n");
> + last_ping = 0;
> + }
> + }
> +
> + watchdog_init_timeout(wdd, heartbeat, dev);
> +
> ret = watchdog_register_device(wdd);
> if (ret) {
> dev_err(dev, "cannot register watchdog device\n");
> goto err_iomap;
> }
>
> + if (last_ping)
> + watchdog_set_last_hw_keepalive(wdd, last_ping);
> +
> return 0;
>
> err_iomap:
>
next prev parent reply other threads:[~2020-07-19 13:56 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-17 13:29 [PATCHv4 0/4] watchdog: rti-wdt: attach to running timer Tero Kristo
2020-07-17 13:29 ` [PATCHv4 1/4] watchdog: use __watchdog_ping in startup Tero Kristo
2020-07-17 13:29 ` [PATCHv4 2/4] watchdog: add support for adjusting last known HW keepalive time Tero Kristo
2020-07-19 13:54 ` Guenter Roeck
2020-07-17 13:29 ` [PATCHv4 3/4] watchdog: rti-wdt: attach to running watchdog during probe Tero Kristo
2020-07-19 13:56 ` Guenter Roeck [this message]
2022-02-21 9:10 ` Jan Kiszka
2022-02-21 9:59 ` Jan Kiszka
2022-02-21 12:44 ` Nishanth Menon
2022-02-21 12:53 ` Jan Kiszka
2022-02-21 16:03 ` Jan Kiszka
2022-02-21 16:29 ` Hari Nagalla
2020-07-17 13:29 ` [PATCHv4 4/4] watchdog: rti-wdt: balance pm runtime enable calls Tero Kristo
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=51c30a7c-a0e3-fc0b-2550-64749480a5fb@roeck-us.net \
--to=linux@roeck-us.net \
--cc=jan.kiszka@siemens.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-watchdog@vger.kernel.org \
--cc=t-kristo@ti.com \
--cc=wim@linux-watchdog.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).