arch/c6x/platforms/timer64.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  Copyright (C) 2010, 2011 Texas Instruments Incorporated
   4  *  Contributed by: Mark Salter (msalter@redhat.com)
   5  */
   6
   7 #include <linux/clockchips.h>
   8 #include <linux/interrupt.h>
   9 #include <linux/io.h>
  10 #include <linux/of.h>
  11 #include <linux/of_irq.h>
  12 #include <linux/of_address.h>
  13 #include <asm/soc.h>
  14 #include <asm/dscr.h>
  15 #include <asm/special_insns.h>
  16 #include <asm/timer64.h>
  17
  18 struct timer_regs {
  19         u32     reserved0;
  20         u32     emumgt;
  21         u32     reserved1;
  22         u32     reserved2;
  23         u32     cntlo;
  24         u32     cnthi;
  25         u32     prdlo;
  26         u32     prdhi;
  27         u32     tcr;
  28         u32     tgcr;
  29         u32     wdtcr;
  30 };
  31
  32 static struct timer_regs __iomem *timer;
  33
  34 #define TCR_TSTATLO          0x001
  35 #define TCR_INVOUTPLO        0x002
  36 #define TCR_INVINPLO         0x004
  37 #define TCR_CPLO             0x008
  38 #define TCR_ENAMODELO_ONCE   0x040
  39 #define TCR_ENAMODELO_CONT   0x080
  40 #define TCR_ENAMODELO_MASK   0x0c0
  41 #define TCR_PWIDLO_MASK      0x030
  42 #define TCR_CLKSRCLO         0x100
  43 #define TCR_TIENLO           0x200
  44 #define TCR_TSTATHI          (0x001 << 16)
  45 #define TCR_INVOUTPHI        (0x002 << 16)
  46 #define TCR_CPHI             (0x008 << 16)
  47 #define TCR_PWIDHI_MASK      (0x030 << 16)
  48 #define TCR_ENAMODEHI_ONCE   (0x040 << 16)
  49 #define TCR_ENAMODEHI_CONT   (0x080 << 16)
  50 #define TCR_ENAMODEHI_MASK   (0x0c0 << 16)
  51
  52 #define TGCR_TIMLORS         0x001
  53 #define TGCR_TIMHIRS         0x002
  54 #define TGCR_TIMMODE_UD32    0x004
  55 #define TGCR_TIMMODE_WDT64   0x008
  56 #define TGCR_TIMMODE_CD32    0x00c
  57 #define TGCR_TIMMODE_MASK    0x00c
  58 #define TGCR_PSCHI_MASK      (0x00f << 8)
  59 #define TGCR_TDDRHI_MASK     (0x00f << 12)
  60
  61 /*
  62  * Timer clocks are divided down from the CPU clock
  63  * The divisor is in the EMUMGTCLKSPD register
  64  */
  65 #define TIMER_DIVISOR \
  66         ((soc_readl(&timer->emumgt) & (0xf << 16)) >> 16)
  67
  68 #define TIMER64_RATE (c6x_core_freq / TIMER_DIVISOR)
  69
  70 #define TIMER64_MODE_DISABLED 0
  71 #define TIMER64_MODE_ONE_SHOT TCR_ENAMODELO_ONCE
  72 #define TIMER64_MODE_PERIODIC TCR_ENAMODELO_CONT
  73
  74 static int timer64_mode;
  75 static int timer64_devstate_id = -1;
  76
  77 static void timer64_config(unsigned long period)
  78 {
  79         u32 tcr = soc_readl(&timer->tcr) & ~TCR_ENAMODELO_MASK;
  80
  81         soc_writel(tcr, &timer->tcr);
  82         soc_writel(period - 1, &timer->prdlo);
  83         soc_writel(0, &timer->cntlo);
  84         tcr |= timer64_mode;
  85         soc_writel(tcr, &timer->tcr);
  86 }
  87
  88 static void timer64_enable(void)
  89 {
  90         u32 val;
  91
  92         if (timer64_devstate_id >= 0)
  93                 dscr_set_devstate(timer64_devstate_id, DSCR_DEVSTATE_ENABLED);
  94
  95         /* disable timer, reset count */
  96         soc_writel(soc_readl(&timer->tcr) & ~TCR_ENAMODELO_MASK, &timer->tcr);
  97         soc_writel(0, &timer->prdlo);
  98
  99         /* use internal clock and 1 cycle pulse width */
 100         val = soc_readl(&timer->tcr);
 101         soc_writel(val & ~(TCR_CLKSRCLO | TCR_PWIDLO_MASK), &timer->tcr);
 102
 103         /* dual 32-bit unchained mode */
 104         val = soc_readl(&timer->tgcr) & ~TGCR_TIMMODE_MASK;
 105         soc_writel(val, &timer->tgcr);
 106         soc_writel(val | (TGCR_TIMLORS | TGCR_TIMMODE_UD32), &timer->tgcr);
 107 }
 108
 109 static void timer64_disable(void)
 110 {
 111         /* disable timer, reset count */
 112         soc_writel(soc_readl(&timer->tcr) & ~TCR_ENAMODELO_MASK, &timer->tcr);
 113         soc_writel(0, &timer->prdlo);
 114
 115         if (timer64_devstate_id >= 0)
 116                 dscr_set_devstate(timer64_devstate_id, DSCR_DEVSTATE_DISABLED);
 117 }
 118
 119 static int next_event(unsigned long delta,
 120                       struct clock_event_device *evt)
 121 {
 122         timer64_config(delta);
 123         return 0;
 124 }
 125
 126 static int set_periodic(struct clock_event_device *evt)
 127 {
 128         timer64_enable();
 129         timer64_mode = TIMER64_MODE_PERIODIC;
 130         timer64_config(TIMER64_RATE / HZ);
 131         return 0;
 132 }
 133
 134 static int set_oneshot(struct clock_event_device *evt)
 135 {
 136         timer64_enable();
 137         timer64_mode = TIMER64_MODE_ONE_SHOT;
 138         return 0;
 139 }
 140
 141 static int shutdown(struct clock_event_device *evt)
 142 {
 143         timer64_mode = TIMER64_MODE_DISABLED;
 144         timer64_disable();
 145         return 0;
 146 }
 147
 148 static struct clock_event_device t64_clockevent_device = {
 149         .name                   = "TIMER64_EVT32_TIMER",
 150         .features               = CLOCK_EVT_FEAT_ONESHOT |
 151                                   CLOCK_EVT_FEAT_PERIODIC,
 152         .rating                 = 200,
 153         .set_state_shutdown     = shutdown,
 154         .set_state_periodic     = set_periodic,
 155         .set_state_oneshot      = set_oneshot,
 156         .set_next_event         = next_event,
 157 };
 158
 159 static irqreturn_t timer_interrupt(int irq, void *dev_id)
 160 {
 161         struct clock_event_device *cd = &t64_clockevent_device;
 162
 163         cd->event_handler(cd);
 164
 165         return IRQ_HANDLED;
 166 }
 167
 168 void __init timer64_init(void)
 169 {
 170         struct clock_event_device *cd = &t64_clockevent_device;
 171         struct device_node *np, *first = NULL;
 172         u32 val;
 173         int err, found = 0;
 174
 175         for_each_compatible_node(np, NULL, "ti,c64x+timer64") {
 176                 err = of_property_read_u32(np, "ti,core-mask", &val);
 177                 if (!err) {
 178                         if (val & (1 << get_coreid())) {
 179                                 found = 1;
 180                                 break;
 181                         }
 182                 } else if (!first)
 183                         first = np;
 184         }
 185         if (!found) {
 186                 /* try first one with no core-mask */
 187                 if (first)
 188                         np = of_node_get(first);
 189                 else {
 190                         pr_debug("Cannot find ti,c64x+timer64 timer.\n");
 191                         return;
 192                 }
 193         }
 194
 195         timer = of_iomap(np, 0);
 196         if (!timer) {
 197                 pr_debug("%pOF: Cannot map timer registers.\n", np);
 198                 goto out;
 199         }
 200         pr_debug("%pOF: Timer registers=%p.\n", np, timer);
 201
 202         cd->irq = irq_of_parse_and_map(np, 0);
 203         if (cd->irq == NO_IRQ) {
 204                 pr_debug("%pOF: Cannot find interrupt.\n", np);
 205                 iounmap(timer);
 206                 goto out;
 207         }
 208
 209         /* If there is a device state control, save the ID. */
 210         err = of_property_read_u32(np, "ti,dscr-dev-enable", &val);
 211         if (!err) {
 212                 timer64_devstate_id = val;
 213
 214                 /*
 215                  * It is necessary to enable the timer block here because
 216                  * the TIMER_DIVISOR macro needs to read a timer register
 217                  * to get the divisor.
 218                  */
 219                 dscr_set_devstate(timer64_devstate_id, DSCR_DEVSTATE_ENABLED);
 220         }
 221
 222         pr_debug("%pOF: Timer irq=%d.\n", np, cd->irq);
 223
 224         clockevents_calc_mult_shift(cd, c6x_core_freq / TIMER_DIVISOR, 5);
 225
 226         cd->max_delta_ns        = clockevent_delta2ns(0x7fffffff, cd);
 227         cd->max_delta_ticks     = 0x7fffffff;
 228         cd->min_delta_ns        = clockevent_delta2ns(250, cd);
 229         cd->min_delta_ticks     = 250;
 230
 231         cd->cpumask             = cpumask_of(smp_processor_id());
 232
 233         clockevents_register_device(cd);
 234         if (request_irq(cd->irq, timer_interrupt, IRQF_TIMER, "timer",
 235                         &t64_clockevent_device))
 236                 pr_err("Failed to request irq %d (timer)\n", cd->irq);
 237
 238 out:
 239         of_node_put(np);
 240         return;
 241 }