Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/clocksource/timer-atmel-tcb.c b/drivers/clocksource/timer-atmel-tcb.c
new file mode 100644
index 0000000..7427b07
--- /dev/null
+++ b/drivers/clocksource/timer-atmel-tcb.c
@@ -0,0 +1,495 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/init.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/ioport.h>
+#include <linux/io.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/sched_clock.h>
+#include <linux/syscore_ops.h>
+#include <soc/at91/atmel_tcb.h>
+
+
+/*
+ * We're configured to use a specific TC block, one that's not hooked
+ * up to external hardware, to provide a time solution:
+ *
+ * - Two channels combine to create a free-running 32 bit counter
+ * with a base rate of 5+ MHz, packaged as a clocksource (with
+ * resolution better than 200 nsec).
+ * - Some chips support 32 bit counter. A single channel is used for
+ * this 32 bit free-running counter. the second channel is not used.
+ *
+ * - The third channel may be used to provide a 16-bit clockevent
+ * source, used in either periodic or oneshot mode. This runs
+ * at 32 KiHZ, and can handle delays of up to two seconds.
+ *
+ * REVISIT behavior during system suspend states... we should disable
+ * all clocks and save the power. Easily done for clockevent devices,
+ * but clocksources won't necessarily get the needed notifications.
+ * For deeper system sleep states, this will be mandatory...
+ */
+
+static void __iomem *tcaddr;
+static struct
+{
+ u32 cmr;
+ u32 imr;
+ u32 rc;
+ bool clken;
+} tcb_cache[3];
+static u32 bmr_cache;
+
+static u64 tc_get_cycles(struct clocksource *cs)
+{
+ unsigned long flags;
+ u32 lower, upper;
+
+ raw_local_irq_save(flags);
+ do {
+ upper = readl_relaxed(tcaddr + ATMEL_TC_REG(1, CV));
+ lower = readl_relaxed(tcaddr + ATMEL_TC_REG(0, CV));
+ } while (upper != readl_relaxed(tcaddr + ATMEL_TC_REG(1, CV)));
+
+ raw_local_irq_restore(flags);
+ return (upper << 16) | lower;
+}
+
+static u64 tc_get_cycles32(struct clocksource *cs)
+{
+ return readl_relaxed(tcaddr + ATMEL_TC_REG(0, CV));
+}
+
+static void tc_clksrc_suspend(struct clocksource *cs)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(tcb_cache); i++) {
+ tcb_cache[i].cmr = readl(tcaddr + ATMEL_TC_REG(i, CMR));
+ tcb_cache[i].imr = readl(tcaddr + ATMEL_TC_REG(i, IMR));
+ tcb_cache[i].rc = readl(tcaddr + ATMEL_TC_REG(i, RC));
+ tcb_cache[i].clken = !!(readl(tcaddr + ATMEL_TC_REG(i, SR)) &
+ ATMEL_TC_CLKSTA);
+ }
+
+ bmr_cache = readl(tcaddr + ATMEL_TC_BMR);
+}
+
+static void tc_clksrc_resume(struct clocksource *cs)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(tcb_cache); i++) {
+ /* Restore registers for the channel, RA and RB are not used */
+ writel(tcb_cache[i].cmr, tcaddr + ATMEL_TC_REG(i, CMR));
+ writel(tcb_cache[i].rc, tcaddr + ATMEL_TC_REG(i, RC));
+ writel(0, tcaddr + ATMEL_TC_REG(i, RA));
+ writel(0, tcaddr + ATMEL_TC_REG(i, RB));
+ /* Disable all the interrupts */
+ writel(0xff, tcaddr + ATMEL_TC_REG(i, IDR));
+ /* Reenable interrupts that were enabled before suspending */
+ writel(tcb_cache[i].imr, tcaddr + ATMEL_TC_REG(i, IER));
+ /* Start the clock if it was used */
+ if (tcb_cache[i].clken)
+ writel(ATMEL_TC_CLKEN, tcaddr + ATMEL_TC_REG(i, CCR));
+ }
+
+ /* Dual channel, chain channels */
+ writel(bmr_cache, tcaddr + ATMEL_TC_BMR);
+ /* Finally, trigger all the channels*/
+ writel(ATMEL_TC_SYNC, tcaddr + ATMEL_TC_BCR);
+}
+
+static struct clocksource clksrc = {
+ .rating = 200,
+ .read = tc_get_cycles,
+ .mask = CLOCKSOURCE_MASK(32),
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+ .suspend = tc_clksrc_suspend,
+ .resume = tc_clksrc_resume,
+};
+
+static u64 notrace tc_sched_clock_read(void)
+{
+ return tc_get_cycles(&clksrc);
+}
+
+static u64 notrace tc_sched_clock_read32(void)
+{
+ return tc_get_cycles32(&clksrc);
+}
+
+static struct delay_timer tc_delay_timer;
+
+static unsigned long tc_delay_timer_read(void)
+{
+ return tc_get_cycles(&clksrc);
+}
+
+static unsigned long notrace tc_delay_timer_read32(void)
+{
+ return tc_get_cycles32(&clksrc);
+}
+
+#ifdef CONFIG_GENERIC_CLOCKEVENTS
+
+struct tc_clkevt_device {
+ struct clock_event_device clkevt;
+ struct clk *clk;
+ void __iomem *regs;
+};
+
+static struct tc_clkevt_device *to_tc_clkevt(struct clock_event_device *clkevt)
+{
+ return container_of(clkevt, struct tc_clkevt_device, clkevt);
+}
+
+/* For now, we always use the 32K clock ... this optimizes for NO_HZ,
+ * because using one of the divided clocks would usually mean the
+ * tick rate can never be less than several dozen Hz (vs 0.5 Hz).
+ *
+ * A divided clock could be good for high resolution timers, since
+ * 30.5 usec resolution can seem "low".
+ */
+static u32 timer_clock;
+
+static int tc_shutdown(struct clock_event_device *d)
+{
+ struct tc_clkevt_device *tcd = to_tc_clkevt(d);
+ void __iomem *regs = tcd->regs;
+
+ writel(0xff, regs + ATMEL_TC_REG(2, IDR));
+ writel(ATMEL_TC_CLKDIS, regs + ATMEL_TC_REG(2, CCR));
+ if (!clockevent_state_detached(d))
+ clk_disable(tcd->clk);
+
+ return 0;
+}
+
+static int tc_set_oneshot(struct clock_event_device *d)
+{
+ struct tc_clkevt_device *tcd = to_tc_clkevt(d);
+ void __iomem *regs = tcd->regs;
+
+ if (clockevent_state_oneshot(d) || clockevent_state_periodic(d))
+ tc_shutdown(d);
+
+ clk_enable(tcd->clk);
+
+ /* slow clock, count up to RC, then irq and stop */
+ writel(timer_clock | ATMEL_TC_CPCSTOP | ATMEL_TC_WAVE |
+ ATMEL_TC_WAVESEL_UP_AUTO, regs + ATMEL_TC_REG(2, CMR));
+ writel(ATMEL_TC_CPCS, regs + ATMEL_TC_REG(2, IER));
+
+ /* set_next_event() configures and starts the timer */
+ return 0;
+}
+
+static int tc_set_periodic(struct clock_event_device *d)
+{
+ struct tc_clkevt_device *tcd = to_tc_clkevt(d);
+ void __iomem *regs = tcd->regs;
+
+ if (clockevent_state_oneshot(d) || clockevent_state_periodic(d))
+ tc_shutdown(d);
+
+ /* By not making the gentime core emulate periodic mode on top
+ * of oneshot, we get lower overhead and improved accuracy.
+ */
+ clk_enable(tcd->clk);
+
+ /* slow clock, count up to RC, then irq and restart */
+ writel(timer_clock | ATMEL_TC_WAVE | ATMEL_TC_WAVESEL_UP_AUTO,
+ regs + ATMEL_TC_REG(2, CMR));
+ writel((32768 + HZ / 2) / HZ, tcaddr + ATMEL_TC_REG(2, RC));
+
+ /* Enable clock and interrupts on RC compare */
+ writel(ATMEL_TC_CPCS, regs + ATMEL_TC_REG(2, IER));
+
+ /* go go gadget! */
+ writel(ATMEL_TC_CLKEN | ATMEL_TC_SWTRG, regs +
+ ATMEL_TC_REG(2, CCR));
+ return 0;
+}
+
+static int tc_next_event(unsigned long delta, struct clock_event_device *d)
+{
+ writel_relaxed(delta, tcaddr + ATMEL_TC_REG(2, RC));
+
+ /* go go gadget! */
+ writel_relaxed(ATMEL_TC_CLKEN | ATMEL_TC_SWTRG,
+ tcaddr + ATMEL_TC_REG(2, CCR));
+ return 0;
+}
+
+static struct tc_clkevt_device clkevt = {
+ .clkevt = {
+ .features = CLOCK_EVT_FEAT_PERIODIC |
+ CLOCK_EVT_FEAT_ONESHOT,
+ /* Should be lower than at91rm9200's system timer */
+ .rating = 125,
+ .set_next_event = tc_next_event,
+ .set_state_shutdown = tc_shutdown,
+ .set_state_periodic = tc_set_periodic,
+ .set_state_oneshot = tc_set_oneshot,
+ },
+};
+
+static irqreturn_t ch2_irq(int irq, void *handle)
+{
+ struct tc_clkevt_device *dev = handle;
+ unsigned int sr;
+
+ sr = readl_relaxed(dev->regs + ATMEL_TC_REG(2, SR));
+ if (sr & ATMEL_TC_CPCS) {
+ dev->clkevt.event_handler(&dev->clkevt);
+ return IRQ_HANDLED;
+ }
+
+ return IRQ_NONE;
+}
+
+static int __init setup_clkevents(struct atmel_tc *tc, int clk32k_divisor_idx)
+{
+ int ret;
+ struct clk *t2_clk = tc->clk[2];
+ int irq = tc->irq[2];
+
+ ret = clk_prepare_enable(tc->slow_clk);
+ if (ret)
+ return ret;
+
+ /* try to enable t2 clk to avoid future errors in mode change */
+ ret = clk_prepare_enable(t2_clk);
+ if (ret) {
+ clk_disable_unprepare(tc->slow_clk);
+ return ret;
+ }
+
+ clk_disable(t2_clk);
+
+ clkevt.regs = tc->regs;
+ clkevt.clk = t2_clk;
+
+ timer_clock = clk32k_divisor_idx;
+
+ clkevt.clkevt.cpumask = cpumask_of(0);
+
+ ret = request_irq(irq, ch2_irq, IRQF_TIMER, "tc_clkevt", &clkevt);
+ if (ret) {
+ clk_unprepare(t2_clk);
+ clk_disable_unprepare(tc->slow_clk);
+ return ret;
+ }
+
+ clockevents_config_and_register(&clkevt.clkevt, 32768, 1, 0xffff);
+
+ return ret;
+}
+
+#else /* !CONFIG_GENERIC_CLOCKEVENTS */
+
+static int __init setup_clkevents(struct atmel_tc *tc, int clk32k_divisor_idx)
+{
+ /* NOTHING */
+ return 0;
+}
+
+#endif
+
+static void __init tcb_setup_dual_chan(struct atmel_tc *tc, int mck_divisor_idx)
+{
+ /* channel 0: waveform mode, input mclk/8, clock TIOA0 on overflow */
+ writel(mck_divisor_idx /* likely divide-by-8 */
+ | ATMEL_TC_WAVE
+ | ATMEL_TC_WAVESEL_UP /* free-run */
+ | ATMEL_TC_ACPA_SET /* TIOA0 rises at 0 */
+ | ATMEL_TC_ACPC_CLEAR, /* (duty cycle 50%) */
+ tcaddr + ATMEL_TC_REG(0, CMR));
+ writel(0x0000, tcaddr + ATMEL_TC_REG(0, RA));
+ writel(0x8000, tcaddr + ATMEL_TC_REG(0, RC));
+ writel(0xff, tcaddr + ATMEL_TC_REG(0, IDR)); /* no irqs */
+ writel(ATMEL_TC_CLKEN, tcaddr + ATMEL_TC_REG(0, CCR));
+
+ /* channel 1: waveform mode, input TIOA0 */
+ writel(ATMEL_TC_XC1 /* input: TIOA0 */
+ | ATMEL_TC_WAVE
+ | ATMEL_TC_WAVESEL_UP, /* free-run */
+ tcaddr + ATMEL_TC_REG(1, CMR));
+ writel(0xff, tcaddr + ATMEL_TC_REG(1, IDR)); /* no irqs */
+ writel(ATMEL_TC_CLKEN, tcaddr + ATMEL_TC_REG(1, CCR));
+
+ /* chain channel 0 to channel 1*/
+ writel(ATMEL_TC_TC1XC1S_TIOA0, tcaddr + ATMEL_TC_BMR);
+ /* then reset all the timers */
+ writel(ATMEL_TC_SYNC, tcaddr + ATMEL_TC_BCR);
+}
+
+static void __init tcb_setup_single_chan(struct atmel_tc *tc, int mck_divisor_idx)
+{
+ /* channel 0: waveform mode, input mclk/8 */
+ writel(mck_divisor_idx /* likely divide-by-8 */
+ | ATMEL_TC_WAVE
+ | ATMEL_TC_WAVESEL_UP, /* free-run */
+ tcaddr + ATMEL_TC_REG(0, CMR));
+ writel(0xff, tcaddr + ATMEL_TC_REG(0, IDR)); /* no irqs */
+ writel(ATMEL_TC_CLKEN, tcaddr + ATMEL_TC_REG(0, CCR));
+
+ /* then reset all the timers */
+ writel(ATMEL_TC_SYNC, tcaddr + ATMEL_TC_BCR);
+}
+
+static const u8 atmel_tcb_divisors[5] = { 2, 8, 32, 128, 0, };
+
+static const struct of_device_id atmel_tcb_of_match[] = {
+ { .compatible = "atmel,at91rm9200-tcb", .data = (void *)16, },
+ { .compatible = "atmel,at91sam9x5-tcb", .data = (void *)32, },
+ { /* sentinel */ }
+};
+
+static int __init tcb_clksrc_init(struct device_node *node)
+{
+ struct atmel_tc tc;
+ struct clk *t0_clk;
+ const struct of_device_id *match;
+ u64 (*tc_sched_clock)(void);
+ u32 rate, divided_rate = 0;
+ int best_divisor_idx = -1;
+ int clk32k_divisor_idx = -1;
+ int bits;
+ int i;
+ int ret;
+
+ /* Protect against multiple calls */
+ if (tcaddr)
+ return 0;
+
+ tc.regs = of_iomap(node->parent, 0);
+ if (!tc.regs)
+ return -ENXIO;
+
+ t0_clk = of_clk_get_by_name(node->parent, "t0_clk");
+ if (IS_ERR(t0_clk))
+ return PTR_ERR(t0_clk);
+
+ tc.slow_clk = of_clk_get_by_name(node->parent, "slow_clk");
+ if (IS_ERR(tc.slow_clk))
+ return PTR_ERR(tc.slow_clk);
+
+ tc.clk[0] = t0_clk;
+ tc.clk[1] = of_clk_get_by_name(node->parent, "t1_clk");
+ if (IS_ERR(tc.clk[1]))
+ tc.clk[1] = t0_clk;
+ tc.clk[2] = of_clk_get_by_name(node->parent, "t2_clk");
+ if (IS_ERR(tc.clk[2]))
+ tc.clk[2] = t0_clk;
+
+ tc.irq[2] = of_irq_get(node->parent, 2);
+ if (tc.irq[2] <= 0) {
+ tc.irq[2] = of_irq_get(node->parent, 0);
+ if (tc.irq[2] <= 0)
+ return -EINVAL;
+ }
+
+ match = of_match_node(atmel_tcb_of_match, node->parent);
+ bits = (uintptr_t)match->data;
+
+ for (i = 0; i < ARRAY_SIZE(tc.irq); i++)
+ writel(ATMEL_TC_ALL_IRQ, tc.regs + ATMEL_TC_REG(i, IDR));
+
+ ret = clk_prepare_enable(t0_clk);
+ if (ret) {
+ pr_debug("can't enable T0 clk\n");
+ return ret;
+ }
+
+ /* How fast will we be counting? Pick something over 5 MHz. */
+ rate = (u32) clk_get_rate(t0_clk);
+ for (i = 0; i < ARRAY_SIZE(atmel_tcb_divisors); i++) {
+ unsigned divisor = atmel_tcb_divisors[i];
+ unsigned tmp;
+
+ /* remember 32 KiHz clock for later */
+ if (!divisor) {
+ clk32k_divisor_idx = i;
+ continue;
+ }
+
+ tmp = rate / divisor;
+ pr_debug("TC: %u / %-3u [%d] --> %u\n", rate, divisor, i, tmp);
+ if (best_divisor_idx > 0) {
+ if (tmp < 5 * 1000 * 1000)
+ continue;
+ }
+ divided_rate = tmp;
+ best_divisor_idx = i;
+ }
+
+ clksrc.name = kbasename(node->parent->full_name);
+ clkevt.clkevt.name = kbasename(node->parent->full_name);
+ pr_debug("%s at %d.%03d MHz\n", clksrc.name, divided_rate / 1000000,
+ ((divided_rate % 1000000) + 500) / 1000);
+
+ tcaddr = tc.regs;
+
+ if (bits == 32) {
+ /* use apropriate function to read 32 bit counter */
+ clksrc.read = tc_get_cycles32;
+ /* setup ony channel 0 */
+ tcb_setup_single_chan(&tc, best_divisor_idx);
+ tc_sched_clock = tc_sched_clock_read32;
+ tc_delay_timer.read_current_timer = tc_delay_timer_read32;
+ } else {
+ /* we have three clocks no matter what the
+ * underlying platform supports.
+ */
+ ret = clk_prepare_enable(tc.clk[1]);
+ if (ret) {
+ pr_debug("can't enable T1 clk\n");
+ goto err_disable_t0;
+ }
+ /* setup both channel 0 & 1 */
+ tcb_setup_dual_chan(&tc, best_divisor_idx);
+ tc_sched_clock = tc_sched_clock_read;
+ tc_delay_timer.read_current_timer = tc_delay_timer_read;
+ }
+
+ /* and away we go! */
+ ret = clocksource_register_hz(&clksrc, divided_rate);
+ if (ret)
+ goto err_disable_t1;
+
+ /* channel 2: periodic and oneshot timer support */
+ ret = setup_clkevents(&tc, clk32k_divisor_idx);
+ if (ret)
+ goto err_unregister_clksrc;
+
+ sched_clock_register(tc_sched_clock, 32, divided_rate);
+
+ tc_delay_timer.freq = divided_rate;
+ register_current_timer_delay(&tc_delay_timer);
+
+ return 0;
+
+err_unregister_clksrc:
+ clocksource_unregister(&clksrc);
+
+err_disable_t1:
+ if (bits != 32)
+ clk_disable_unprepare(tc.clk[1]);
+
+err_disable_t0:
+ clk_disable_unprepare(t0_clk);
+
+ tcaddr = NULL;
+
+ return ret;
+}
+TIMER_OF_DECLARE(atmel_tcb_clksrc, "atmel,tcb-timer", tcb_clksrc_init);