158 lines
3.2 KiB
C
158 lines
3.2 KiB
C
/*
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* H8S TPU Driver
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*
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* Copyright 2015 Yoshinori Sato <ysato@users.sourcefoge.jp>
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*
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*/
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#include <linux/errno.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/clocksource.h>
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#include <linux/clk.h>
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#include <linux/io.h>
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#include <linux/of.h>
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#include <linux/of_address.h>
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#include <linux/of_irq.h>
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#define TCR 0x0
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#define TSR 0x5
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#define TCNT 0x6
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#define TCFV 0x10
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struct tpu_priv {
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struct clocksource cs;
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void __iomem *mapbase1;
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void __iomem *mapbase2;
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raw_spinlock_t lock;
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unsigned int cs_enabled;
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};
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static inline unsigned long read_tcnt32(struct tpu_priv *p)
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{
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unsigned long tcnt;
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tcnt = ioread16be(p->mapbase1 + TCNT) << 16;
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tcnt |= ioread16be(p->mapbase2 + TCNT);
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return tcnt;
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}
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static int tpu_get_counter(struct tpu_priv *p, unsigned long long *val)
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{
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unsigned long v1, v2, v3;
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int o1, o2;
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o1 = ioread8(p->mapbase1 + TSR) & TCFV;
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/* Make sure the timer value is stable. Stolen from acpi_pm.c */
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do {
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o2 = o1;
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v1 = read_tcnt32(p);
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v2 = read_tcnt32(p);
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v3 = read_tcnt32(p);
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o1 = ioread8(p->mapbase1 + TSR) & TCFV;
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} while (unlikely((o1 != o2) || (v1 > v2 && v1 < v3)
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|| (v2 > v3 && v2 < v1) || (v3 > v1 && v3 < v2)));
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*val = v2;
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return o1;
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}
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static inline struct tpu_priv *cs_to_priv(struct clocksource *cs)
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{
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return container_of(cs, struct tpu_priv, cs);
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}
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static u64 tpu_clocksource_read(struct clocksource *cs)
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{
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struct tpu_priv *p = cs_to_priv(cs);
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unsigned long flags;
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unsigned long long value;
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raw_spin_lock_irqsave(&p->lock, flags);
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if (tpu_get_counter(p, &value))
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value += 0x100000000;
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raw_spin_unlock_irqrestore(&p->lock, flags);
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return value;
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}
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static int tpu_clocksource_enable(struct clocksource *cs)
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{
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struct tpu_priv *p = cs_to_priv(cs);
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WARN_ON(p->cs_enabled);
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iowrite16be(0, p->mapbase1 + TCNT);
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iowrite16be(0, p->mapbase2 + TCNT);
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iowrite8(0x0f, p->mapbase1 + TCR);
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iowrite8(0x03, p->mapbase2 + TCR);
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p->cs_enabled = true;
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return 0;
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}
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static void tpu_clocksource_disable(struct clocksource *cs)
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{
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struct tpu_priv *p = cs_to_priv(cs);
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WARN_ON(!p->cs_enabled);
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iowrite8(0, p->mapbase1 + TCR);
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iowrite8(0, p->mapbase2 + TCR);
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p->cs_enabled = false;
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}
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static struct tpu_priv tpu_priv = {
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.cs = {
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.name = "H8S_TPU",
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.rating = 200,
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.read = tpu_clocksource_read,
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.enable = tpu_clocksource_enable,
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.disable = tpu_clocksource_disable,
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.mask = CLOCKSOURCE_MASK(sizeof(unsigned long) * 8),
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.flags = CLOCK_SOURCE_IS_CONTINUOUS,
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},
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};
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#define CH_L 0
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#define CH_H 1
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static int __init h8300_tpu_init(struct device_node *node)
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{
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void __iomem *base[2];
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struct clk *clk;
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int ret = -ENXIO;
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clk = of_clk_get(node, 0);
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if (IS_ERR(clk)) {
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pr_err("failed to get clock for clocksource\n");
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return PTR_ERR(clk);
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}
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base[CH_L] = of_iomap(node, CH_L);
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if (!base[CH_L]) {
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pr_err("failed to map registers for clocksource\n");
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goto free_clk;
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}
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base[CH_H] = of_iomap(node, CH_H);
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if (!base[CH_H]) {
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pr_err("failed to map registers for clocksource\n");
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goto unmap_L;
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}
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tpu_priv.mapbase1 = base[CH_L];
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tpu_priv.mapbase2 = base[CH_H];
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return clocksource_register_hz(&tpu_priv.cs, clk_get_rate(clk) / 64);
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unmap_L:
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iounmap(base[CH_H]);
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free_clk:
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clk_put(clk);
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return ret;
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}
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CLOCKSOURCE_OF_DECLARE(h8300_tpu, "renesas,tpu", h8300_tpu_init);
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