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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-19 10:09:22 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-19 10:09:22 -0700 |
| commit | f4cdf7ca9a1fdcca413157df19753f388a5a224e (patch) | |
| tree | 60a31895b2446cd7fa27514e8c2843534a0de0da /drivers/clocksource/timer-atmel-st.c | |
| download | linux-stable-f4cdf7ca9a1fdcca413157df19753f388a5a224e.tar.gz linux-stable-f4cdf7ca9a1fdcca413157df19753f388a5a224e.zip | |
Merge tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-mediagrafted
Pull media updates from Mauro Carvalho Chehab:
- v4l2-core: added ISP statistics support and per-block validation
- v4l2-core: Allow unknown HDR10 white point and luminance
- New camera sensors: Sony IMX678 and IMX471m, Himax HM1092 IR sensor
- New codec: Milos: VPU v2.0 codec support
- isp driver: gained support for Dreamchip RPPX1 ISP framework
- vsp1 driver: gained support for RZ/T2H and RZ/N2H
- Novalake driver: gained CVS support for new NVL hardware
- dvb-core: fix feed leak on failed DMX_ADD_PID
- several driver fixes, cleanups and minor improvements
* tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (308 commits)
media: ipu-bridge: check all DMI entries when overriding sensor rotation
media: v4l2-async: avoid deleting unlinked ASC entry on link error
media: rzg2l-cru: Align bytesperline to hardware DMA stride requirement
media: intel/ipu6: fix async notifier cleanup leak on parse error
media: staging/ipu7: fix async notifier UAF on probe error path
media: amd: isp4: fix self-deadlock in isp4sd_pwron_and_init() error path
media: amd: isp4: release partial allocations in isp4if_alloc_fw_gpumem()
media: rcar-isp: Fix VSPX reference leaks
media: rcar-isp: Release ISPCORE resources
media: i2c: imx415: Release runtime PM reference on VBLANK error
media: i2c: imx415: Return test pattern write errors
media: renesas: vsp1: Declare index variables in for loop statement
media: renesas: vsp1: Make reset control optional to support platforms without a reset line
media: dt-bindings: media: renesas,vsp1: Document RZ/T2H and RZ/N2H SoCs
media: dt-bindings: media: renesas,fcp: Document RZ/T2H and RZ/N2H SoCs
media: nxp: imx8-isi: Add additional 32-bit RGB format support
media: nxp: imx8-isi: Add 16-bit raw Bayer format support
media: nxp: imx8-isi: Implement per-stream reference counting for multiplexed streams
media: nxp: imx8-isi: Use BIT_ULL() for 64-bit stream masks
media: nxp: imx8-isi: Correct color map between V4L2 and ISI
...
Diffstat (limited to 'drivers/clocksource/timer-atmel-st.c')
| -rw-r--r-- | drivers/clocksource/timer-atmel-st.c | 250 |
1 files changed, 250 insertions, 0 deletions
diff --git a/drivers/clocksource/timer-atmel-st.c b/drivers/clocksource/timer-atmel-st.c new file mode 100644 index 000000000..73e8aee44 --- /dev/null +++ b/drivers/clocksource/timer-atmel-st.c @@ -0,0 +1,250 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * linux/arch/arm/mach-at91/at91rm9200_time.c + * + * Copyright (C) 2003 SAN People + * Copyright (C) 2003 ATMEL + */ + +#include <linux/kernel.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/clk.h> +#include <linux/clockchips.h> +#include <linux/export.h> +#include <linux/mfd/syscon.h> +#include <linux/mfd/syscon/atmel-st.h> +#include <linux/of_irq.h> +#include <linux/regmap.h> + +static unsigned long last_crtr; +static u32 irqmask; +static struct clock_event_device clkevt; +static struct regmap *regmap_st; +static int timer_latch; + +/* + * The ST_CRTR is updated asynchronously to the master clock ... but + * the updates as seen by the CPU don't seem to be strictly monotonic. + * Waiting until we read the same value twice avoids glitching. + */ +static inline unsigned long read_CRTR(void) +{ + unsigned int x1, x2; + + regmap_read(regmap_st, AT91_ST_CRTR, &x1); + do { + regmap_read(regmap_st, AT91_ST_CRTR, &x2); + if (x1 == x2) + break; + x1 = x2; + } while (1); + return x1; +} + +/* + * IRQ handler for the timer. + */ +static irqreturn_t at91rm9200_timer_interrupt(int irq, void *dev_id) +{ + u32 sr; + + regmap_read(regmap_st, AT91_ST_SR, &sr); + sr &= irqmask; + + /* + * irqs should be disabled here, but as the irq is shared they are only + * guaranteed to be off if the timer irq is registered first. + */ + WARN_ON_ONCE(!irqs_disabled()); + + /* simulate "oneshot" timer with alarm */ + if (sr & AT91_ST_ALMS) { + clkevt.event_handler(&clkevt); + return IRQ_HANDLED; + } + + /* periodic mode should handle delayed ticks */ + if (sr & AT91_ST_PITS) { + u32 crtr = read_CRTR(); + + while (((crtr - last_crtr) & AT91_ST_CRTV) >= timer_latch) { + last_crtr += timer_latch; + clkevt.event_handler(&clkevt); + } + return IRQ_HANDLED; + } + + /* this irq is shared ... */ + return IRQ_NONE; +} + +static u64 read_clk32k(struct clocksource *cs) +{ + return read_CRTR(); +} + +static struct clocksource clk32k = { + .name = "32k_counter", + .rating = 150, + .read = read_clk32k, + .mask = CLOCKSOURCE_MASK(20), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +static void clkdev32k_disable_and_flush_irq(void) +{ + unsigned int val; + + /* Disable and flush pending timer interrupts */ + regmap_write(regmap_st, AT91_ST_IDR, AT91_ST_PITS | AT91_ST_ALMS); + regmap_read(regmap_st, AT91_ST_SR, &val); + last_crtr = read_CRTR(); +} + +static int clkevt32k_shutdown(struct clock_event_device *evt) +{ + clkdev32k_disable_and_flush_irq(); + irqmask = 0; + regmap_write(regmap_st, AT91_ST_IER, irqmask); + return 0; +} + +static int clkevt32k_set_oneshot(struct clock_event_device *dev) +{ + clkdev32k_disable_and_flush_irq(); + + /* + * ALM for oneshot irqs, set by next_event() + * before 32 seconds have passed. + */ + irqmask = AT91_ST_ALMS; + regmap_write(regmap_st, AT91_ST_RTAR, last_crtr); + regmap_write(regmap_st, AT91_ST_IER, irqmask); + return 0; +} + +static int clkevt32k_set_periodic(struct clock_event_device *dev) +{ + clkdev32k_disable_and_flush_irq(); + + /* PIT for periodic irqs; fixed rate of 1/HZ */ + irqmask = AT91_ST_PITS; + regmap_write(regmap_st, AT91_ST_PIMR, timer_latch); + regmap_write(regmap_st, AT91_ST_IER, irqmask); + return 0; +} + +static int +clkevt32k_next_event(unsigned long delta, struct clock_event_device *dev) +{ + u32 alm; + unsigned int val; + + BUG_ON(delta < 2); + + /* The alarm IRQ uses absolute time (now+delta), not the relative + * time (delta) in our calling convention. Like all clockevents + * using such "match" hardware, we have a race to defend against. + * + * Our defense here is to have set up the clockevent device so the + * delta is at least two. That way we never end up writing RTAR + * with the value then held in CRTR ... which would mean the match + * wouldn't trigger until 32 seconds later, after CRTR wraps. + */ + alm = read_CRTR(); + + /* Cancel any pending alarm; flush any pending IRQ */ + regmap_write(regmap_st, AT91_ST_RTAR, alm); + regmap_read(regmap_st, AT91_ST_SR, &val); + + /* Schedule alarm by writing RTAR. */ + alm += delta; + regmap_write(regmap_st, AT91_ST_RTAR, alm); + + return 0; +} + +static struct clock_event_device clkevt = { + .name = "at91_tick", + .features = CLOCK_EVT_FEAT_PERIODIC | + CLOCK_EVT_FEAT_ONESHOT, + .rating = 150, + .set_next_event = clkevt32k_next_event, + .set_state_shutdown = clkevt32k_shutdown, + .set_state_periodic = clkevt32k_set_periodic, + .set_state_oneshot = clkevt32k_set_oneshot, + .tick_resume = clkevt32k_shutdown, +}; + +/* + * ST (system timer) module supports both clockevents and clocksource. + */ +static int __init atmel_st_timer_init(struct device_node *node) +{ + struct clk *sclk; + unsigned int sclk_rate, val; + int irq, ret; + + regmap_st = syscon_node_to_regmap(node); + if (IS_ERR(regmap_st)) { + pr_err("Unable to get regmap\n"); + return PTR_ERR(regmap_st); + } + + /* Disable all timer interrupts, and clear any pending ones */ + regmap_write(regmap_st, AT91_ST_IDR, + AT91_ST_PITS | AT91_ST_WDOVF | AT91_ST_RTTINC | AT91_ST_ALMS); + regmap_read(regmap_st, AT91_ST_SR, &val); + + /* Get the interrupts property */ + irq = irq_of_parse_and_map(node, 0); + if (!irq) { + pr_err("Unable to get IRQ from DT\n"); + return -EINVAL; + } + + /* Make IRQs happen for the system timer */ + ret = request_irq(irq, at91rm9200_timer_interrupt, + IRQF_SHARED | IRQF_TIMER | IRQF_IRQPOLL, + "at91_tick", regmap_st); + if (ret) { + pr_err("Unable to setup IRQ\n"); + return ret; + } + + sclk = of_clk_get(node, 0); + if (IS_ERR(sclk)) { + pr_err("Unable to get slow clock\n"); + return PTR_ERR(sclk); + } + + ret = clk_prepare_enable(sclk); + if (ret) { + pr_err("Could not enable slow clock\n"); + return ret; + } + + sclk_rate = clk_get_rate(sclk); + if (!sclk_rate) { + pr_err("Invalid slow clock rate\n"); + return -EINVAL; + } + timer_latch = (sclk_rate + HZ / 2) / HZ; + + /* The 32KiHz "Slow Clock" (tick every 30517.58 nanoseconds) is used + * directly for the clocksource and all clockevents, after adjusting + * its prescaler from the 1 Hz default. + */ + regmap_write(regmap_st, AT91_ST_RTMR, 1); + + /* Setup timer clockevent, with minimum of two ticks (important!!) */ + clkevt.cpumask = cpumask_of(0); + clockevents_config_and_register(&clkevt, sclk_rate, + 2, AT91_ST_ALMV); + + /* register clocksource */ + return clocksource_register_hz(&clk32k, sclk_rate); +} +TIMER_OF_DECLARE(atmel_st_timer, "atmel,at91rm9200-st", + atmel_st_timer_init); |
