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path: root/drivers/watchdog/dw_wdt.c
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Diffstat (limited to 'drivers/watchdog/dw_wdt.c')
-rw-r--r--drivers/watchdog/dw_wdt.c191
1 files changed, 167 insertions, 24 deletions
diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c
index fba21de2bbad..693c0d1fd796 100644
--- a/drivers/watchdog/dw_wdt.c
+++ b/drivers/watchdog/dw_wdt.c
@@ -13,6 +13,8 @@
*/
#include <linux/bitops.h>
+#include <linux/limits.h>
+#include <linux/kernel.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/err.h>
@@ -34,21 +36,40 @@
#define WDOG_CURRENT_COUNT_REG_OFFSET 0x08
#define WDOG_COUNTER_RESTART_REG_OFFSET 0x0c
#define WDOG_COUNTER_RESTART_KICK_VALUE 0x76
+#define WDOG_COMP_PARAMS_1_REG_OFFSET 0xf4
+#define WDOG_COMP_PARAMS_1_USE_FIX_TOP BIT(6)
-/* The maximum TOP (timeout period) value that can be set in the watchdog. */
-#define DW_WDT_MAX_TOP 15
+/* There are sixteen TOPs (timeout periods) that can be set in the watchdog. */
+#define DW_WDT_NUM_TOPS 16
+#define DW_WDT_FIX_TOP(_idx) (1U << (16 + _idx))
#define DW_WDT_DEFAULT_SECONDS 30
+static const u32 dw_wdt_fix_tops[DW_WDT_NUM_TOPS] = {
+ DW_WDT_FIX_TOP(0), DW_WDT_FIX_TOP(1), DW_WDT_FIX_TOP(2),
+ DW_WDT_FIX_TOP(3), DW_WDT_FIX_TOP(4), DW_WDT_FIX_TOP(5),
+ DW_WDT_FIX_TOP(6), DW_WDT_FIX_TOP(7), DW_WDT_FIX_TOP(8),
+ DW_WDT_FIX_TOP(9), DW_WDT_FIX_TOP(10), DW_WDT_FIX_TOP(11),
+ DW_WDT_FIX_TOP(12), DW_WDT_FIX_TOP(13), DW_WDT_FIX_TOP(14),
+ DW_WDT_FIX_TOP(15)
+};
+
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+struct dw_wdt_timeout {
+ u32 top_val;
+ unsigned int sec;
+ unsigned int msec;
+};
+
struct dw_wdt {
void __iomem *regs;
struct clk *clk;
unsigned long rate;
+ struct dw_wdt_timeout timeouts[DW_WDT_NUM_TOPS];
struct watchdog_device wdd;
struct reset_control *rst;
/* Save/restore */
@@ -64,20 +85,66 @@ static inline int dw_wdt_is_enabled(struct dw_wdt *dw_wdt)
WDOG_CONTROL_REG_WDT_EN_MASK;
}
-static inline int dw_wdt_top_in_seconds(struct dw_wdt *dw_wdt, unsigned top)
+static unsigned int dw_wdt_find_best_top(struct dw_wdt *dw_wdt,
+ unsigned int timeout, u32 *top_val)
{
+ int idx;
+
/*
- * There are 16 possible timeout values in 0..15 where the number of
- * cycles is 2 ^ (16 + i) and the watchdog counts down.
+ * Find a TOP with timeout greater or equal to the requested number.
+ * Note we'll select a TOP with maximum timeout if the requested
+ * timeout couldn't be reached.
*/
- return (1U << (16 + top)) / dw_wdt->rate;
+ for (idx = 0; idx < DW_WDT_NUM_TOPS; ++idx) {
+ if (dw_wdt->timeouts[idx].sec >= timeout)
+ break;
+ }
+
+ if (idx == DW_WDT_NUM_TOPS)
+ --idx;
+
+ *top_val = dw_wdt->timeouts[idx].top_val;
+
+ return dw_wdt->timeouts[idx].sec;
}
-static int dw_wdt_get_top(struct dw_wdt *dw_wdt)
+static unsigned int dw_wdt_get_min_timeout(struct dw_wdt *dw_wdt)
{
- int top = readl(dw_wdt->regs + WDOG_TIMEOUT_RANGE_REG_OFFSET) & 0xF;
+ int idx;
+
+ /*
+ * We'll find a timeout greater or equal to one second anyway because
+ * the driver probe would have failed if there was none.
+ */
+ for (idx = 0; idx < DW_WDT_NUM_TOPS; ++idx) {
+ if (dw_wdt->timeouts[idx].sec)
+ break;
+ }
- return dw_wdt_top_in_seconds(dw_wdt, top);
+ return dw_wdt->timeouts[idx].sec;
+}
+
+static unsigned int dw_wdt_get_max_timeout_ms(struct dw_wdt *dw_wdt)
+{
+ struct dw_wdt_timeout *timeout = &dw_wdt->timeouts[DW_WDT_NUM_TOPS - 1];
+ u64 msec;
+
+ msec = (u64)timeout->sec * MSEC_PER_SEC + timeout->msec;
+
+ return msec < UINT_MAX ? msec : UINT_MAX;
+}
+
+static unsigned int dw_wdt_get_timeout(struct dw_wdt *dw_wdt)
+{
+ int top_val = readl(dw_wdt->regs + WDOG_TIMEOUT_RANGE_REG_OFFSET) & 0xF;
+ int idx;
+
+ for (idx = 0; idx < DW_WDT_NUM_TOPS; ++idx) {
+ if (dw_wdt->timeouts[idx].top_val == top_val)
+ break;
+ }
+
+ return dw_wdt->timeouts[idx].sec;
}
static int dw_wdt_ping(struct watchdog_device *wdd)
@@ -93,17 +160,10 @@ static int dw_wdt_ping(struct watchdog_device *wdd)
static int dw_wdt_set_timeout(struct watchdog_device *wdd, unsigned int top_s)
{
struct dw_wdt *dw_wdt = to_dw_wdt(wdd);
- int i, top_val = DW_WDT_MAX_TOP;
+ unsigned int timeout;
+ u32 top_val;
- /*
- * Iterate over the timeout values until we find the closest match. We
- * always look for >=.
- */
- for (i = 0; i <= DW_WDT_MAX_TOP; ++i)
- if (dw_wdt_top_in_seconds(dw_wdt, i) >= top_s) {
- top_val = i;
- break;
- }
+ timeout = dw_wdt_find_best_top(dw_wdt, top_s, &top_val);
/*
* Set the new value in the watchdog. Some versions of dw_wdt
@@ -120,7 +180,7 @@ static int dw_wdt_set_timeout(struct watchdog_device *wdd, unsigned int top_s)
* wdd->max_hw_heartbeat_ms
*/
if (top_s * 1000 <= wdd->max_hw_heartbeat_ms)
- wdd->timeout = dw_wdt_top_in_seconds(dw_wdt, top_val);
+ wdd->timeout = timeout;
else
wdd->timeout = top_s;
@@ -238,6 +298,86 @@ static int dw_wdt_resume(struct device *dev)
static SIMPLE_DEV_PM_OPS(dw_wdt_pm_ops, dw_wdt_suspend, dw_wdt_resume);
+/*
+ * In case if DW WDT IP core is synthesized with fixed TOP feature disabled the
+ * TOPs array can be arbitrary ordered with nearly any sixteen uint numbers
+ * depending on the system engineer imagination. The next method handles the
+ * passed TOPs array to pre-calculate the effective timeouts and to sort the
+ * TOP items out in the ascending order with respect to the timeouts.
+ */
+
+static void dw_wdt_handle_tops(struct dw_wdt *dw_wdt, const u32 *tops)
+{
+ struct dw_wdt_timeout tout, *dst;
+ int val, tidx;
+ u64 msec;
+
+ /*
+ * We walk over the passed TOPs array and calculate corresponding
+ * timeouts in seconds and milliseconds. The milliseconds granularity
+ * is needed to distinguish the TOPs with very close timeouts and to
+ * set the watchdog max heartbeat setting further.
+ */
+ for (val = 0; val < DW_WDT_NUM_TOPS; ++val) {
+ tout.top_val = val;
+ tout.sec = tops[val] / dw_wdt->rate;
+ msec = (u64)tops[val] * MSEC_PER_SEC;
+ do_div(msec, dw_wdt->rate);
+ tout.msec = msec - ((u64)tout.sec * MSEC_PER_SEC);
+
+ /*
+ * Find a suitable place for the current TOP in the timeouts
+ * array so that the list is remained in the ascending order.
+ */
+ for (tidx = 0; tidx < val; ++tidx) {
+ dst = &dw_wdt->timeouts[tidx];
+ if (tout.sec > dst->sec || (tout.sec == dst->sec &&
+ tout.msec >= dst->msec))
+ continue;
+ else
+ swap(*dst, tout);
+ }
+
+ dw_wdt->timeouts[val] = tout;
+ }
+}
+
+static int dw_wdt_init_timeouts(struct dw_wdt *dw_wdt, struct device *dev)
+{
+ u32 data, of_tops[DW_WDT_NUM_TOPS];
+ const u32 *tops;
+ int ret;
+
+ /*
+ * Retrieve custom or fixed counter values depending on the
+ * WDT_USE_FIX_TOP flag found in the component specific parameters
+ * #1 register.
+ */
+ data = readl(dw_wdt->regs + WDOG_COMP_PARAMS_1_REG_OFFSET);
+ if (data & WDOG_COMP_PARAMS_1_USE_FIX_TOP) {
+ tops = dw_wdt_fix_tops;
+ } else {
+ ret = of_property_read_variable_u32_array(dev_of_node(dev),
+ "snps,watchdog-tops", of_tops, DW_WDT_NUM_TOPS,
+ DW_WDT_NUM_TOPS);
+ if (ret < 0) {
+ dev_warn(dev, "No valid TOPs array specified\n");
+ tops = dw_wdt_fix_tops;
+ } else {
+ tops = of_tops;
+ }
+ }
+
+ /* Convert the specified TOPs into an array of watchdog timeouts. */
+ dw_wdt_handle_tops(dw_wdt, tops);
+ if (!dw_wdt->timeouts[DW_WDT_NUM_TOPS - 1].sec) {
+ dev_err(dev, "No any valid TOP detected\n");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
static int dw_wdt_drv_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
@@ -275,12 +415,15 @@ static int dw_wdt_drv_probe(struct platform_device *pdev)
reset_control_deassert(dw_wdt->rst);
+ ret = dw_wdt_init_timeouts(dw_wdt, dev);
+ if (ret)
+ goto out_disable_clk;
+
wdd = &dw_wdt->wdd;
wdd->info = &dw_wdt_ident;
wdd->ops = &dw_wdt_ops;
- wdd->min_timeout = 1;
- wdd->max_hw_heartbeat_ms =
- dw_wdt_top_in_seconds(dw_wdt, DW_WDT_MAX_TOP) * 1000;
+ wdd->min_timeout = dw_wdt_get_min_timeout(dw_wdt);
+ wdd->max_hw_heartbeat_ms = dw_wdt_get_max_timeout_ms(dw_wdt);
wdd->parent = dev;
watchdog_set_drvdata(wdd, dw_wdt);
@@ -293,7 +436,7 @@ static int dw_wdt_drv_probe(struct platform_device *pdev)
* devicetree.
*/
if (dw_wdt_is_enabled(dw_wdt)) {
- wdd->timeout = dw_wdt_get_top(dw_wdt);
+ wdd->timeout = dw_wdt_get_timeout(dw_wdt);
set_bit(WDOG_HW_RUNNING, &wdd->status);
} else {
wdd->timeout = DW_WDT_DEFAULT_SECONDS;