arm64: ac5: Fix watchdog timeleft (#334)

Watchdog timeleft returns unexpected huge value for first read,
followed by correct expected values. Unexpected huge value reappears
after few minutes. Issue is resolved by updating the existing
hardware workaround to read WCV_HI along with WCV_LO.

Signed-off-by: Pradeep Turaga Shakthi <[email protected]>
Co-authored-by: Saikrishna Arcot <[email protected]>

Author: pavannaregundi

patch/0015-ac5-marvell-Add-watchdog-support.patch

@@ -12,8 +12,8 @@ Signed-off-by: Noam Liron <[email protected]>
 ---
  drivers/watchdog/Kconfig   |  16 ++
  drivers/watchdog/Makefile  |   1 +
- drivers/watchdog/ac5_gwd.c | 458 +++++++++++++++++++++++++++++++++++++
- 3 files changed, 475 insertions(+)
+ drivers/watchdog/ac5_gwd.c | 459 +++++++++++++++++++++++++++++++++++++
+ 3 files changed, 476 insertions(+)
  create mode 100644 drivers/watchdog/ac5_gwd.c
 
 diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
@@ -57,10 +57,10 @@ index 071a2e50b..acf3df558 100644
  obj-$(CONFIG_AT91SAM9X_WATCHDOG) += at91sam9_wdt.o
 diff --git a/drivers/watchdog/ac5_gwd.c b/drivers/watchdog/ac5_gwd.c
 new file mode 100644
-index 000000000..5ba877b9b
+index 000000000..994d1a2db
 --- /dev/null
 +++ b/drivers/watchdog/ac5_gwd.c
-@@ -0,0 +1,458 @@
+@@ -0,0 +1,459 @@
 +// SPDX-License-Identifier: GPL-2.0
 +/*
 + * AC5 Watchdog driver
@@ -244,6 +244,7 @@ index 000000000..5ba877b9b
 +	low = smc_readl(addr);
 +	high = smc_readl(addr + 4);
 +	low = smc_readl(addr); /* read twice, as a workaround to HW limitation */
++	high = smc_readl(addr + 4); /* read twice, as a workaround to HW limitation */
 +
 +	return low + ((u64)high << 32);
 +}