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158 lines
3.2 KiB
158 lines
3.2 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* H8S TPU Driver |
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* |
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* Copyright 2015 Yoshinori Sato <[email protected]> |
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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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TIMER_OF_DECLARE(h8300_tpu, "renesas,tpu", h8300_tpu_init);
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