diff options
Diffstat (limited to 'drivers/timer/arc_timer.c')
-rw-r--r-- | drivers/timer/arc_timer.c | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/drivers/timer/arc_timer.c b/drivers/timer/arc_timer.c new file mode 100644 index 00000000000..e94e4a4bca7 --- /dev/null +++ b/drivers/timer/arc_timer.c @@ -0,0 +1,113 @@ +/* + * Copyright (C) 2016 Synopsys, Inc. All rights reserved. + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#include <common.h> +#include <dm.h> +#include <errno.h> +#include <timer.h> +#include <asm/arcregs.h> +#include <asm/io.h> + +DECLARE_GLOBAL_DATA_PTR; + +#define NH_MODE (1 << 1) + +/* + * ARC timer control registers are mapped to auxiliary address space. + * There are special ARC asm command to access that addresses. + * Therefore we use built-in functions to read from and write to timer + * control register. + */ + +/* Driver private data. Contains timer id. Could be either 0 or 1. */ +struct arc_timer_priv { + uint timer_id; +}; + +static int arc_timer_get_count(struct udevice *dev, u64 *count) +{ + u32 val = 0; + struct arc_timer_priv *priv = dev_get_priv(dev); + + switch (priv->timer_id) { + case 0: + val = read_aux_reg(ARC_AUX_TIMER0_CNT); + break; + case 1: + val = read_aux_reg(ARC_AUX_TIMER1_CNT); + break; + } + *count = timer_conv_64(val); + + return 0; +} + +static int arc_timer_probe(struct udevice *dev) +{ + int id; + struct arc_timer_priv *priv = dev_get_priv(dev); + + /* Get registers offset and size */ + id = fdtdec_get_int(gd->fdt_blob, dev->of_offset, "reg", -1); + if (id < 0) + return -EINVAL; + + if (id > 1) + return -ENXIO; + + priv->timer_id = (uint)id; + + /* + * In ARC core there're special registers (Auxiliary or AUX) in its + * separate memory space that are used for accessing some hardware + * features of the core. They are not mapped in normal memory space + * and also always have the same location regardless core configuration. + * Thus to simplify understanding of the programming model we chose to + * access AUX regs of Timer0 and Timer1 separately instead of using + * offsets from some base address. + */ + + switch (priv->timer_id) { + case 0: + /* Disable timer if CPU is halted */ + write_aux_reg(ARC_AUX_TIMER0_CTRL, NH_MODE); + /* Set max value for counter/timer */ + write_aux_reg(ARC_AUX_TIMER0_LIMIT, 0xffffffff); + /* Set initial count value and restart counter/timer */ + write_aux_reg(ARC_AUX_TIMER0_CNT, 0); + break; + case 1: + /* Disable timer if CPU is halted */ + write_aux_reg(ARC_AUX_TIMER1_CTRL, NH_MODE); + /* Set max value for counter/timer */ + write_aux_reg(ARC_AUX_TIMER1_LIMIT, 0xffffffff); + /* Set initial count value and restart counter/timer */ + write_aux_reg(ARC_AUX_TIMER1_CNT, 0); + break; + } + + return 0; +} + + +static const struct timer_ops arc_timer_ops = { + .get_count = arc_timer_get_count, +}; + +static const struct udevice_id arc_timer_ids[] = { + { .compatible = "snps,arc-timer" }, + {} +}; + +U_BOOT_DRIVER(arc_timer) = { + .name = "arc_timer", + .id = UCLASS_TIMER, + .of_match = arc_timer_ids, + .probe = arc_timer_probe, + .ops = &arc_timer_ops, + .flags = DM_FLAG_PRE_RELOC, + .priv_auto_alloc_size = sizeof(struct arc_timer_priv), +}; |