Commit 5184f4bf authored by Nick Hawkins's avatar Nick Hawkins Committed by Arnd Bergmann

clocksource/drivers/timer-gxp: Add HPE GXP Timer

Add support for the HPE GXP SOC timer. The GXP supports several different
kinds of timers but for the purpose of this driver there is only support
for the General Timer. The timer has a 1us resolution and is 32 bits. The
timer also creates a child watchdog device as the register region is the
same.
Signed-off-by: default avatarNick Hawkins <nick.hawkins@hpe.com>
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
parent 6b47441b
......@@ -617,6 +617,14 @@ config CLKSRC_ST_LPC
Enable this option to use the Low Power controller timer
as clocksource.
config GXP_TIMER
bool "GXP timer driver" if COMPILE_TEST && !ARCH_HPE
default ARCH_HPE
select TIMER_OF if OF
help
Provides a driver for the timer control found on HPE
GXP SOCs. This is required for all GXP SOCs.
config RISCV_TIMER
bool "Timer for the RISC-V platform" if COMPILE_TEST
depends on GENERIC_SCHED_CLOCK && RISCV && RISCV_SBI
......
......@@ -88,3 +88,4 @@ obj-$(CONFIG_GX6605S_TIMER) += timer-gx6605s.o
obj-$(CONFIG_HYPERV_TIMER) += hyperv_timer.o
obj-$(CONFIG_MICROCHIP_PIT64B) += timer-microchip-pit64b.o
obj-$(CONFIG_MSC313E_TIMER) += timer-msc313e.o
obj-$(CONFIG_GXP_TIMER) += timer-gxp.o
// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) 2022 Hewlett-Packard Enterprise Development Company, L.P. */
#include <linux/clk.h>
#include <linux/clockchips.h>
#include <linux/clocksource.h>
#include <linux/interrupt.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/of_platform.h>
#include <linux/sched_clock.h>
#define TIMER0_FREQ 1000000
#define GXP_TIMER_CNT_OFS 0x00
#define GXP_TIMESTAMP_OFS 0x08
#define GXP_TIMER_CTRL_OFS 0x14
/* TCS Stands for Timer Control/Status: these are masks to be used in */
/* the Timer Count Registers */
#define MASK_TCS_ENABLE 0x01
#define MASK_TCS_PERIOD 0x02
#define MASK_TCS_RELOAD 0x04
#define MASK_TCS_TC 0x80
struct gxp_timer {
void __iomem *counter;
void __iomem *control;
struct clock_event_device evt;
};
static struct gxp_timer *gxp_timer;
static void __iomem *system_clock __ro_after_init;
static inline struct gxp_timer *to_gxp_timer(struct clock_event_device *evt_dev)
{
return container_of(evt_dev, struct gxp_timer, evt);
}
static u64 notrace gxp_sched_read(void)
{
return readl_relaxed(system_clock);
}
static int gxp_time_set_next_event(unsigned long event, struct clock_event_device *evt_dev)
{
struct gxp_timer *timer = to_gxp_timer(evt_dev);
/* Stop counting and disable interrupt before updating */
writeb_relaxed(MASK_TCS_TC, timer->control);
writel_relaxed(event, timer->counter);
writeb_relaxed(MASK_TCS_TC | MASK_TCS_ENABLE, timer->control);
return 0;
}
static irqreturn_t gxp_timer_interrupt(int irq, void *dev_id)
{
struct gxp_timer *timer = (struct gxp_timer *)dev_id;
if (!(readb_relaxed(timer->control) & MASK_TCS_TC))
return IRQ_NONE;
writeb_relaxed(MASK_TCS_TC, timer->control);
timer->evt.event_handler(&timer->evt);
return IRQ_HANDLED;
}
static int __init gxp_timer_init(struct device_node *node)
{
void __iomem *base;
struct clk *clk;
u32 freq;
int ret, irq;
gxp_timer = kzalloc(sizeof(*gxp_timer), GFP_KERNEL);
if (!gxp_timer) {
ret = -ENOMEM;
pr_err("Can't allocate gxp_timer");
return ret;
}
clk = of_clk_get(node, 0);
if (IS_ERR(clk)) {
ret = (int)PTR_ERR(clk);
pr_err("%pOFn clock not found: %d\n", node, ret);
goto err_free;
}
ret = clk_prepare_enable(clk);
if (ret) {
pr_err("%pOFn clock enable failed: %d\n", node, ret);
goto err_clk_enable;
}
base = of_iomap(node, 0);
if (!base) {
ret = -ENXIO;
pr_err("Can't map timer base registers");
goto err_iomap;
}
/* Set the offsets to the clock register and timer registers */
gxp_timer->counter = base + GXP_TIMER_CNT_OFS;
gxp_timer->control = base + GXP_TIMER_CTRL_OFS;
system_clock = base + GXP_TIMESTAMP_OFS;
gxp_timer->evt.name = node->name;
gxp_timer->evt.rating = 300;
gxp_timer->evt.features = CLOCK_EVT_FEAT_ONESHOT;
gxp_timer->evt.set_next_event = gxp_time_set_next_event;
gxp_timer->evt.cpumask = cpumask_of(0);
irq = irq_of_parse_and_map(node, 0);
if (irq <= 0) {
ret = -EINVAL;
pr_err("GXP Timer Can't parse IRQ %d", irq);
goto err_exit;
}
freq = clk_get_rate(clk);
ret = clocksource_mmio_init(system_clock, node->name, freq,
300, 32, clocksource_mmio_readl_up);
if (ret) {
pr_err("%pOFn init clocksource failed: %d", node, ret);
goto err_exit;
}
sched_clock_register(gxp_sched_read, 32, freq);
irq = irq_of_parse_and_map(node, 0);
if (irq <= 0) {
ret = -EINVAL;
pr_err("%pOFn Can't parse IRQ %d", node, irq);
goto err_exit;
}
clockevents_config_and_register(&gxp_timer->evt, TIMER0_FREQ,
0xf, 0xffffffff);
ret = request_irq(irq, gxp_timer_interrupt, IRQF_TIMER | IRQF_SHARED,
node->name, gxp_timer);
if (ret) {
pr_err("%pOFn request_irq() failed: %d", node, ret);
goto err_exit;
}
pr_debug("gxp: system timer (irq = %d)\n", irq);
return 0;
err_exit:
iounmap(base);
err_iomap:
clk_disable_unprepare(clk);
err_clk_enable:
clk_put(clk);
err_free:
kfree(gxp_timer);
return ret;
}
/*
* This probe gets called after the timer is already up and running. This will create
* the watchdog device as a child since the registers are shared.
*/
static int gxp_timer_probe(struct platform_device *pdev)
{
struct platform_device *gxp_watchdog_device;
struct device *dev = &pdev->dev;
if (!gxp_timer) {
pr_err("Gxp Timer not initialized, cannot create watchdog");
return -ENOMEM;
}
gxp_watchdog_device = platform_device_alloc("gxp-wdt", -1);
if (!gxp_watchdog_device) {
pr_err("Timer failed to allocate gxp-wdt");
return -ENOMEM;
}
/* Pass the base address (counter) as platform data and nothing else */
gxp_watchdog_device->dev.platform_data = gxp_timer->counter;
gxp_watchdog_device->dev.parent = dev;
return platform_device_add(gxp_watchdog_device);
}
static const struct of_device_id gxp_timer_of_match[] = {
{ .compatible = "hpe,gxp-timer", },
{},
};
static struct platform_driver gxp_timer_driver = {
.probe = gxp_timer_probe,
.driver = {
.name = "gxp-timer",
.of_match_table = gxp_timer_of_match,
.suppress_bind_attrs = true,
},
};
builtin_platform_driver(gxp_timer_driver);
TIMER_OF_DECLARE(gxp, "hpe,gxp-timer", gxp_timer_init);
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