109 lines
2.6 KiB
C
109 lines
2.6 KiB
C
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// SPDX-License-Identifier: GPL-2.0+
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/*
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* ARM PrimeCell Dual-Timer Module (SP804) driver
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* Copyright (C) 2022 Arm Ltd.
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*/
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#include <common.h>
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#include <clk.h>
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#include <dm.h>
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#include <init.h>
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#include <log.h>
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#include <asm/global_data.h>
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#include <dm/ofnode.h>
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#include <mapmem.h>
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#include <dt-structs.h>
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#include <timer.h>
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#include <asm/io.h>
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DECLARE_GLOBAL_DATA_PTR;
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#define SP804_TIMERX_LOAD 0x00
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#define SP804_TIMERX_VALUE 0x04
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#define SP804_TIMERX_CONTROL 0x08
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#define SP804_CTRL_TIMER_ENABLE (1U << 7)
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#define SP804_CTRL_TIMER_PERIODIC (1U << 6)
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#define SP804_CTRL_INT_ENABLE (1U << 5)
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#define SP804_CTRL_TIMER_PRESCALE_SHIFT 2
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#define SP804_CTRL_TIMER_PRESCALE_MASK (3U << SP804_CTRL_TIMER_PRESCALE_SHIFT)
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#define SP804_CTRL_TIMER_32BIT (1U << 1)
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#define SP804_CTRL_ONESHOT (1U << 0)
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struct sp804_timer_plat {
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uintptr_t base;
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};
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static u64 sp804_timer_get_count(struct udevice *dev)
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{
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struct sp804_timer_plat *plat = dev_get_plat(dev);
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uint32_t cntr = readl(plat->base + SP804_TIMERX_VALUE);
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/* timers are down-counting */
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return ~0u - cntr;
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}
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static int sp804_clk_of_to_plat(struct udevice *dev)
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{
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struct sp804_timer_plat *plat = dev_get_plat(dev);
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plat->base = dev_read_addr(dev);
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if (!plat->base)
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return -ENOENT;
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return 0;
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}
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static int sp804_timer_probe(struct udevice *dev)
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{
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struct sp804_timer_plat *plat = dev_get_plat(dev);
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struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
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struct clk base_clk;
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unsigned int divider = 1;
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uint32_t ctlr;
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int ret;
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ctlr = readl(plat->base + SP804_TIMERX_CONTROL);
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ctlr &= SP804_CTRL_TIMER_PRESCALE_MASK;
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switch (ctlr >> SP804_CTRL_TIMER_PRESCALE_SHIFT) {
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case 0x0: divider = 1; break;
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case 0x1: divider = 16; break;
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case 0x2: divider = 256; break;
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case 0x3: printf("illegal!\n"); break;
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}
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ret = clk_get_by_index(dev, 0, &base_clk);
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if (ret) {
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printf("could not find SP804 timer base clock in DT\n");
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return ret;
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}
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uc_priv->clock_rate = clk_get_rate(&base_clk) / divider;
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/* keep divider, free-running, wrapping, no IRQs, 32-bit mode */
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ctlr |= SP804_CTRL_TIMER_32BIT | SP804_CTRL_TIMER_ENABLE;
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writel(ctlr, plat->base + SP804_TIMERX_CONTROL);
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return 0;
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}
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static const struct timer_ops sp804_timer_ops = {
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.get_count = sp804_timer_get_count,
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};
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static const struct udevice_id sp804_timer_ids[] = {
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{ .compatible = "arm,sp804" },
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{}
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};
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U_BOOT_DRIVER(arm_sp804_timer) = {
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.name = "arm_sp804_timer",
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.id = UCLASS_TIMER,
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.of_match = sp804_timer_ids,
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.probe = sp804_timer_probe,
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.ops = &sp804_timer_ops,
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.plat_auto = sizeof(struct sp804_timer_plat),
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.of_to_plat = sp804_clk_of_to_plat,
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};
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