1 /* 2 * Copyright (C) 2016 Synopsys, Inc. All rights reserved. 3 * 4 * SPDX-License-Identifier: GPL-2.0+ 5 */ 6 7 #include <common.h> 8 #include <dm.h> 9 #include <errno.h> 10 #include <timer.h> 11 #include <asm/arcregs.h> 12 #include <asm/io.h> 13 14 DECLARE_GLOBAL_DATA_PTR; 15 16 #define NH_MODE (1 << 1) 17 18 /* 19 * ARC timer control registers are mapped to auxiliary address space. 20 * There are special ARC asm command to access that addresses. 21 * Therefore we use built-in functions to read from and write to timer 22 * control register. 23 */ 24 25 /* Driver private data. Contains timer id. Could be either 0 or 1. */ 26 struct arc_timer_priv { 27 uint timer_id; 28 }; 29 30 static int arc_timer_get_count(struct udevice *dev, u64 *count) 31 { 32 u32 val = 0; 33 struct arc_timer_priv *priv = dev_get_priv(dev); 34 35 switch (priv->timer_id) { 36 case 0: 37 val = read_aux_reg(ARC_AUX_TIMER0_CNT); 38 break; 39 case 1: 40 val = read_aux_reg(ARC_AUX_TIMER1_CNT); 41 break; 42 } 43 *count = timer_conv_64(val); 44 45 return 0; 46 } 47 48 static int arc_timer_probe(struct udevice *dev) 49 { 50 int id; 51 struct arc_timer_priv *priv = dev_get_priv(dev); 52 53 /* Get registers offset and size */ 54 id = fdtdec_get_int(gd->fdt_blob, dev->of_offset, "reg", -1); 55 if (id < 0) 56 return -EINVAL; 57 58 if (id > 1) 59 return -ENXIO; 60 61 priv->timer_id = (uint)id; 62 63 /* 64 * In ARC core there're special registers (Auxiliary or AUX) in its 65 * separate memory space that are used for accessing some hardware 66 * features of the core. They are not mapped in normal memory space 67 * and also always have the same location regardless core configuration. 68 * Thus to simplify understanding of the programming model we chose to 69 * access AUX regs of Timer0 and Timer1 separately instead of using 70 * offsets from some base address. 71 */ 72 73 switch (priv->timer_id) { 74 case 0: 75 /* Disable timer if CPU is halted */ 76 write_aux_reg(ARC_AUX_TIMER0_CTRL, NH_MODE); 77 /* Set max value for counter/timer */ 78 write_aux_reg(ARC_AUX_TIMER0_LIMIT, 0xffffffff); 79 /* Set initial count value and restart counter/timer */ 80 write_aux_reg(ARC_AUX_TIMER0_CNT, 0); 81 break; 82 case 1: 83 /* Disable timer if CPU is halted */ 84 write_aux_reg(ARC_AUX_TIMER1_CTRL, NH_MODE); 85 /* Set max value for counter/timer */ 86 write_aux_reg(ARC_AUX_TIMER1_LIMIT, 0xffffffff); 87 /* Set initial count value and restart counter/timer */ 88 write_aux_reg(ARC_AUX_TIMER1_CNT, 0); 89 break; 90 } 91 92 return 0; 93 } 94 95 96 static const struct timer_ops arc_timer_ops = { 97 .get_count = arc_timer_get_count, 98 }; 99 100 static const struct udevice_id arc_timer_ids[] = { 101 { .compatible = "snps,arc-timer" }, 102 {} 103 }; 104 105 U_BOOT_DRIVER(arc_timer) = { 106 .name = "arc_timer", 107 .id = UCLASS_TIMER, 108 .of_match = arc_timer_ids, 109 .probe = arc_timer_probe, 110 .ops = &arc_timer_ops, 111 .flags = DM_FLAG_PRE_RELOC, 112 .priv_auto_alloc_size = sizeof(struct arc_timer_priv), 113 }; 114