diff options
Diffstat (limited to 'drivers/timer/atmel_tcb_timer.c')
| -rw-r--r-- | drivers/timer/atmel_tcb_timer.c | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/drivers/timer/atmel_tcb_timer.c b/drivers/timer/atmel_tcb_timer.c new file mode 100644 index 0000000..8c17987 --- /dev/null +++ b/drivers/timer/atmel_tcb_timer.c @@ -0,0 +1,161 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (C) 2022 Microchip Corporation + * + * Author: Clément Léger <clement.leger@bootlin.com> + */ + +#include <common.h> +#include <clk.h> +#include <dm.h> +#include <timer.h> +#include <asm/io.h> +#include <linux/bitops.h> + +#define TCB_CHAN(chan) ((chan) * 0x40) + +#define TCB_CCR(chan) (0x0 + TCB_CHAN(chan)) +#define TCB_CCR_CLKEN (1 << 0) + +#define TCB_CMR(chan) (0x4 + TCB_CHAN(chan)) +#define TCB_CMR_WAVE (1 << 15) +#define TCB_CMR_TIMER_CLOCK2 1 +#define TCB_CMR_XC1 6 +#define TCB_CMR_ACPA_SET (1 << 16) +#define TCB_CMR_ACPC_CLEAR (2 << 18) + +#define TCB_CV(chan) (0x10 + TCB_CHAN(chan)) + +#define TCB_RA(chan) (0x14 + TCB_CHAN(chan)) +#define TCB_RC(chan) (0x1c + TCB_CHAN(chan)) + +#define TCB_IDR(chan) (0x28 + TCB_CHAN(chan)) + +#define TCB_BCR 0xc0 +#define TCB_BCR_SYNC (1 << 0) + +#define TCB_BMR 0xc4 +#define TCB_BMR_TC1XC1S_TIOA0 (2 << 2) + +#define TCB_WPMR 0xe4 +#define TCB_WPMR_WAKEY 0x54494d + +#define TCB_CLK_DIVISOR 8 +struct atmel_tcb_plat { + void __iomem *base; +}; + +static u64 atmel_tcb_get_count(struct udevice *dev) +{ + struct atmel_tcb_plat *plat = dev_get_plat(dev); + u64 cv0 = 0; + u64 cv1 = 0; + + do { + cv1 = readl(plat->base + TCB_CV(1)); + cv0 = readl(plat->base + TCB_CV(0)); + } while (readl(plat->base + TCB_CV(1)) != cv1); + + cv0 |= cv1 << 32; + + return cv0; +} + +static void atmel_tcb_configure(void __iomem *base) +{ + /* Disable write protection */ + writel(TCB_WPMR_WAKEY, base + TCB_WPMR); + + /* Disable all irqs for both channel 0 & 1 */ + writel(0xff, base + TCB_IDR(0)); + writel(0xff, base + TCB_IDR(1)); + + /* + * In order to avoid wrapping, use a 64 bit counter by chaining + * two channels. + * Channel 0 is configured to generate a clock on TIOA0 which is cleared + * when reaching 0x80000000 and set when reaching 0. + */ + writel(TCB_CMR_TIMER_CLOCK2 | TCB_CMR_WAVE | TCB_CMR_ACPA_SET + | TCB_CMR_ACPC_CLEAR, base + TCB_CMR(0)); + writel(0x80000000, base + TCB_RC(0)); + writel(0x1, base + TCB_RA(0)); + writel(TCB_CCR_CLKEN, base + TCB_CCR(0)); + + /* Channel 1 is configured to use TIOA0 as input */ + writel(TCB_CMR_XC1 | TCB_CMR_WAVE, base + TCB_CMR(1)); + writel(TCB_CCR_CLKEN, base + TCB_CCR(1)); + + /* Set XC1 input to be TIOA0 (ie output of Channel 0) */ + writel(TCB_BMR_TC1XC1S_TIOA0, base + TCB_BMR); + + /* Sync & start all timers */ + writel(TCB_BCR_SYNC, base + TCB_BCR); +} + +static int atmel_tcb_probe(struct udevice *dev) +{ + struct atmel_tcb_plat *plat = dev_get_plat(dev); + struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev); + struct clk clk; + ulong clk_rate; + int ret; + + if (!device_is_compatible(dev->parent, "atmel,sama5d2-tcb")) + return -EINVAL; + + /* Currently, we only support channel 0 and 1 to be chained */ + if (dev_read_addr_index(dev, 0) != 0 && + dev_read_addr_index(dev, 1) != 1) { + printf("Error: only chained timers 0 and 1 are supported\n"); + return -EINVAL; + } + + ret = clk_get_by_name(dev->parent, "t0_clk", &clk); + if (ret) + return -EINVAL; + + ret = clk_enable(&clk); + if (ret) + return ret; + + clk_rate = clk_get_rate(&clk); + if (!clk_rate) { + clk_disable(&clk); + return -EINVAL; + } + + uc_priv->clock_rate = clk_rate / TCB_CLK_DIVISOR; + + atmel_tcb_configure(plat->base); + + return 0; +} + +static int atmel_tcb_of_to_plat(struct udevice *dev) +{ + struct atmel_tcb_plat *plat = dev_get_plat(dev); + + plat->base = dev_read_addr_ptr(dev->parent); + + return 0; +} + +static const struct timer_ops atmel_tcb_ops = { + .get_count = atmel_tcb_get_count, +}; + +static const struct udevice_id atmel_tcb_ids[] = { + { .compatible = "atmel,tcb-timer" }, + { } +}; + +U_BOOT_DRIVER(atmel_tcb) = { + .name = "atmel_tcb", + .id = UCLASS_TIMER, + .of_match = atmel_tcb_ids, + .of_to_plat = atmel_tcb_of_to_plat, + .plat_auto = sizeof(struct atmel_tcb_plat), + .probe = atmel_tcb_probe, + .ops = &atmel_tcb_ops, +}; |