From 017af7f71ae6e2943027f4ce44b51fd36cd89c39 Mon Sep 17 00:00:00 2001 From: Chris Packham Date: Fri, 5 Mar 2021 16:32:58 +1300 Subject: [PATCH] watchdog: Add booke watchdog driver Add a driver for the PowerPC Book E watchdog driver that is present on a number of Freescale/NXP SoCs. Signed-off-by: Chris Packham Reviewed-by: Stefan Roese Reviewed-by: Priyanka Jain --- drivers/watchdog/Kconfig | 7 +++ drivers/watchdog/Makefile | 1 + drivers/watchdog/booke_wdt.c | 106 +++++++++++++++++++++++++++++++++++ 3 files changed, 114 insertions(+) create mode 100644 drivers/watchdog/booke_wdt.c diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig index aa76a8f2d2..f0ff2612a6 100644 --- a/drivers/watchdog/Kconfig +++ b/drivers/watchdog/Kconfig @@ -124,6 +124,13 @@ config WDT_BCM6345 The watchdog timer is stopped when initialized. It performs full SoC reset. +config WDT_BOOKE + bool "PowerPC Book-E watchdog driver" + depends on WDT && MPC85xx + help + Watchdog driver for PowerPC Book-E chips, such as the Freescale + MPC85xx SOCs and the IBM PowerPC 440. + config WDT_CDNS bool "Cadence watchdog timer support" depends on WDT diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile index 6e70c7ae19..5c7ef593fe 100644 --- a/drivers/watchdog/Makefile +++ b/drivers/watchdog/Makefile @@ -21,6 +21,7 @@ obj-$(CONFIG_WDT_ARMADA_37XX) += armada-37xx-wdt.o obj-$(CONFIG_WDT_ASPEED) += ast_wdt.o obj-$(CONFIG_WDT_AST2600) += ast2600_wdt.o obj-$(CONFIG_WDT_BCM6345) += bcm6345_wdt.o +obj-$(CONFIG_WDT_BOOKE) += booke_wdt.o obj-$(CONFIG_WDT_CORTINA) += cortina_wdt.o obj-$(CONFIG_WDT_ORION) += orion_wdt.o obj-$(CONFIG_WDT_CDNS) += cdns_wdt.o diff --git a/drivers/watchdog/booke_wdt.c b/drivers/watchdog/booke_wdt.c new file mode 100644 index 0000000000..50c091956e --- /dev/null +++ b/drivers/watchdog/booke_wdt.c @@ -0,0 +1,106 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Watchdog timer for PowerPC Book-E systems + */ + +#include +#include +#include +#include + +#define WDTP_MASK TCR_WP(0x3f) + +/* For the specified period, determine the number of seconds + * corresponding to the reset time. There will be a watchdog + * exception at approximately 3/5 of this time. + * + * The formula to calculate this is given by: + * 2.5 * (2^(63-period+1)) / timebase_freq + * + * In order to simplify things, we assume that period is + * at least 1. This will still result in a very long timeout. + */ +static unsigned long long period_to_sec(unsigned int period) +{ + unsigned long long tmp = 1ULL << (64 - period); + unsigned long tmp2 = get_tbclk(); + + /* tmp may be a very large number and we don't want to overflow, + * so divide the timebase freq instead of multiplying tmp + */ + tmp2 = tmp2 / 5 * 2; + + do_div(tmp, tmp2); + return tmp; +} + +/* + * This procedure will find the highest period which will give a timeout + * greater than the one required. e.g. for a bus speed of 66666666 and + * and a parameter of 2 secs, then this procedure will return a value of 38. + */ +static unsigned int sec_to_period(unsigned int secs) +{ + unsigned int period; + + for (period = 63; period > 0; period--) { + if (period_to_sec(period) >= secs) + return period; + } + return 0; +} + +static int booke_wdt_reset(struct udevice *dev) +{ + mtspr(SPRN_TSR, TSR_ENW | TSR_WIS); + + return 0; +} + +static int booke_wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags) +{ + u32 val; + unsigned int timeout = DIV_ROUND_UP(timeout_ms, 1000); + + /* clear status before enabling watchdog */ + booke_wdt_reset(dev); + val = mfspr(SPRN_TCR); + val &= ~WDTP_MASK; + val |= (TCR_WIE | TCR_WRC(WRC_CHIP) | TCR_WP(sec_to_period(timeout))); + + mtspr(SPRN_TCR, val); + + return 0; +} + +static int booke_wdt_stop(struct udevice *dev) +{ + u32 val; + + val = mfspr(SPRN_TCR); + val &= ~(TCR_WIE | WDTP_MASK); + mtspr(SPRN_TCR, val); + + /* clear status to make sure nothing is pending */ + booke_wdt_reset(dev); + + return 0; +} + +static const struct wdt_ops booke_wdt_ops = { + .start = booke_wdt_start, + .stop = booke_wdt_stop, + .reset = booke_wdt_reset, +}; + +static const struct udevice_id booke_wdt_ids[] = { + { .compatible = "fsl,booke-wdt" }, + {} +}; + +U_BOOT_DRIVER(booke_wdt) = { + .name = "booke_wdt", + .id = UCLASS_WDT, + .of_match = booke_wdt_ids, + .ops = &booke_wdt_ops, +};