target/linux/ramips/patches-3.10/0022-clocksource-MIPS-ralink-add-support-for-systick-time.patch

   1 From 10cb446ac01be52c49b5143c8601524bc4f53051 Mon Sep 17 00:00:00 2001
   2 From: John Crispin <blogic@openwrt.org>
   3 Date: Sun, 14 Jul 2013 23:11:05 +0200
   4 Subject: [PATCH 22/33] clocksource: MIPS: ralink: add support for systick
   5  timer found on newer ralink SoC
   6
   7 Signed-off-by: John Crispin <blogic@openwrt.org>
   8 ---
   9  arch/mips/ralink/Kconfig          |    2 +
  10  arch/mips/ralink/clk.c            |    1 +
  11  drivers/clocksource/Kconfig       |    6 ++
  12  drivers/clocksource/Makefile      |    1 +
  13  drivers/clocksource/cevt-rt3352.c |  162 +++++++++++++++++++++++++++++++++++++
  14  5 files changed, 172 insertions(+)
  15  create mode 100644 drivers/clocksource/cevt-rt3352.c
  16
  17 --- a/arch/mips/ralink/Kconfig
  18 +++ b/arch/mips/ralink/Kconfig
  19 @@ -15,6 +15,7 @@ choice
  20                 select USB_ARCH_HAS_HCD
  21                 select USB_ARCH_HAS_OHCI
  22                 select USB_ARCH_HAS_EHCI
  23 +               select CLKEVT_RT3352
  24
  25         config SOC_RT3883
  26                 bool "RT3883"
  27 @@ -27,6 +28,7 @@ choice
  28                 select USB_ARCH_HAS_OHCI
  29                 select USB_ARCH_HAS_EHCI
  30                 select HW_HAS_PCI
  31 +               select CLKEVT_RT3352
  32
  33  endchoice
  34
  35 --- a/arch/mips/ralink/clk.c
  36 +++ b/arch/mips/ralink/clk.c
  37 @@ -69,4 +69,5 @@ void __init plat_time_init(void)
  38         pr_info("CPU Clock: %ldMHz\n", clk_get_rate(clk) / 1000000);
  39         mips_hpt_frequency = clk_get_rate(clk) / 2;
  40         clk_put(clk);
  41 +       clocksource_of_init();
  42  }
  43 --- a/drivers/clocksource/Kconfig
  44 +++ b/drivers/clocksource/Kconfig
  45 @@ -7,6 +7,12 @@ config CLKSRC_I8253
  46  config CLKEVT_I8253
  47         bool
  48
  49 +config CLKEVT_RT3352
  50 +       bool
  51 +       depends on MIPS && RALINK
  52 +       select CLKSRC_OF
  53 +       select CLKSRC_MMIO
  54 +
  55  config I8253_LOCK
  56         bool
  57
  58 --- a/drivers/clocksource/Makefile
  59 +++ b/drivers/clocksource/Makefile
  60 @@ -10,6 +10,7 @@ obj-$(CONFIG_SH_TIMER_TMU)    += sh_tmu.o
  61  obj-$(CONFIG_EM_TIMER_STI)     += em_sti.o
  62  obj-$(CONFIG_CLKBLD_I8253)     += i8253.o
  63  obj-$(CONFIG_CLKSRC_MMIO)      += mmio.o
  64 +obj-$(CONFIG_CLKEVT_RT3352)    += cevt-rt3352.o
  65  obj-$(CONFIG_DW_APB_TIMER)     += dw_apb_timer.o
  66  obj-$(CONFIG_DW_APB_TIMER_OF)  += dw_apb_timer_of.o
  67  obj-$(CONFIG_CLKSRC_NOMADIK_MTU)       += nomadik-mtu.o
  68 --- /dev/null
  69 +++ b/drivers/clocksource/cevt-rt3352.c
  70 @@ -0,0 +1,162 @@
  71 +/*
  72 + * This file is subject to the terms and conditions of the GNU General Public
  73 + * License.  See the file "COPYING" in the main directory of this archive
  74 + * for more details.
  75 + *
  76 + * Copyright (C) 2013 by John Crispin <blogic@openwrt.org>
  77 + */
  78 +
  79 +#include <linux/clockchips.h>
  80 +#include <linux/clocksource.h>
  81 +#include <linux/interrupt.h>
  82 +#include <linux/reset.h>
  83 +#include <linux/init.h>
  84 +#include <linux/of.h>
  85 +#include <linux/of_irq.h>
  86 +#include <linux/of_address.h>
  87 +
  88 +#include <asm/mach-ralink/ralink_regs.h>
  89 +#include <asm/time.h>
  90 +
  91 +#define SYSTICK_FREQ   (50 * 1000)
  92 +
  93 +#define SYSTICK_CONFIG 0x00
  94 +#define SYSTICK_COMPARE        0x04
  95 +#define SYSTICK_COUNT  0x08
  96 +
  97 +/* route systick irq to mips irq 7 instead of the r4k-timer */
  98 +#define CFG_EXT_STK_EN 0x2
  99 +/* enable the counter */
 100 +#define CFG_CNT_EN     0x1
 101 +
 102 +struct systick_device {
 103 +       void __iomem *membase;
 104 +       struct clock_event_device dev;
 105 +       int irq_requested;
 106 +       int freq_scale;
 107 +};
 108 +
 109 +static void systick_set_clock_mode(enum clock_event_mode mode,
 110 +                               struct clock_event_device *evt);
 111 +
 112 +static int systick_next_event(unsigned long delta,
 113 +                               struct clock_event_device *evt)
 114 +{
 115 +       struct systick_device *sdev = container_of(evt, struct systick_device, dev);
 116 +       u32 count;
 117 +
 118 +       count = ioread32(sdev->membase + SYSTICK_COUNT);
 119 +       count = (count + delta) % SYSTICK_FREQ;
 120 +       iowrite32(count + delta, sdev->membase + SYSTICK_COMPARE);
 121 +
 122 +       return 0;
 123 +}
 124 +
 125 +static void systick_event_handler(struct clock_event_device *dev)
 126 +{
 127 +       /* noting to do here */
 128 +}
 129 +
 130 +static irqreturn_t systick_interrupt(int irq, void *dev_id)
 131 +{
 132 +       struct clock_event_device *dev = (struct clock_event_device *) dev_id;
 133 +
 134 +       dev->event_handler(dev);
 135 +
 136 +       return IRQ_HANDLED;
 137 +}
 138 +
 139 +static struct systick_device systick = {
 140 +       .dev = {
 141 +               /* cevt-r4k uses 300, make sure systick gets used if available */
 142 +               .rating         = 310,
 143 +               .features       = CLOCK_EVT_FEAT_ONESHOT,
 144 +               .set_next_event = systick_next_event,
 145 +               .set_mode       = systick_set_clock_mode,
 146 +               .event_handler  = systick_event_handler,
 147 +       },
 148 +};
 149 +
 150 +static struct irqaction systick_irqaction = {
 151 +       .handler = systick_interrupt,
 152 +       .flags = IRQF_PERCPU | IRQF_TIMER,
 153 +       .dev_id = &systick.dev,
 154 +};
 155 +
 156 +/* ugly hack */
 157 +#ifdef CONFIG_SOC_MT7620
 158 +
 159 +#define CLK_LUT_CFG    0x40
 160 +#define SLEEP_EN       BIT(31)
 161 +
 162 +static inline void mt7620_freq_scaling(struct systick_device *sdev, int status)
 163 +{
 164 +       if (sdev->freq_scale == status)
 165 +               return;
 166 +
 167 +       sdev->freq_scale = status;
 168 +
 169 +       pr_info("%s: %s autosleep mode\n", systick.dev.name, (status) ? ("enable") : ("disable"));
 170 +       if (status)
 171 +               rt_sysc_w32(rt_sysc_r32(CLK_LUT_CFG) | SLEEP_EN, CLK_LUT_CFG);
 172 +       else
 173 +               rt_sysc_w32(rt_sysc_r32(CLK_LUT_CFG) & ~SLEEP_EN, CLK_LUT_CFG);
 174 +}
 175 +#else
 176 +static inline void mt7620_freq_scaling(struct systick_device *sdev, int status) {}
 177 +#endif
 178 +
 179 +static void systick_set_clock_mode(enum clock_event_mode mode,
 180 +                               struct clock_event_device *evt)
 181 +{
 182 +       struct systick_device *sdev = container_of(evt, struct systick_device, dev);
 183 +
 184 +       switch (mode) {
 185 +       case CLOCK_EVT_MODE_ONESHOT:
 186 +               if (!sdev->irq_requested)
 187 +                       setup_irq(systick.dev.irq, &systick_irqaction);
 188 +               mt7620_freq_scaling(sdev, 1);
 189 +               sdev->irq_requested = 1;
 190 +               iowrite32(CFG_EXT_STK_EN | CFG_CNT_EN, systick.membase + SYSTICK_CONFIG);
 191 +               break;
 192 +
 193 +       case CLOCK_EVT_MODE_SHUTDOWN:
 194 +               if (sdev->irq_requested)
 195 +                       free_irq(systick.dev.irq, &systick_irqaction);
 196 +               mt7620_freq_scaling(sdev, 0);
 197 +               sdev->irq_requested = 0;
 198 +               iowrite32(0, systick.membase + SYSTICK_CONFIG);
 199 +               break;
 200 +
 201 +       default:
 202 +               pr_err("%s: Unhandeled mips clock_mode\n", systick.dev.name);
 203 +               break;
 204 +       }
 205 +}
 206 +
 207 +static void __init ralink_systick_init(struct device_node *np)
 208 +{
 209 +       systick.membase = of_iomap(np, 0);
 210 +       if (!systick.membase) {
 211 +               pr_err("%s: of_iomap failed", np->name);
 212 +               return;
 213 +       }
 214 +
 215 +       clocksource_mmio_init(systick.membase + SYSTICK_COUNT, np->name,
 216 +                       SYSTICK_FREQ, 301, 16, clocksource_mmio_readl_up);
 217 +
 218 +       systick_irqaction.name = np->name;
 219 +       systick.dev.name = np->name;
 220 +       clockevent_set_clock(&systick.dev, SYSTICK_FREQ);
 221 +       systick.dev.max_delta_ns = clockevent_delta2ns(0x7fff, &systick.dev);
 222 +       systick.dev.min_delta_ns = clockevent_delta2ns(0x3, &systick.dev);
 223 +       systick.dev.irq = irq_of_parse_and_map(np, 0);
 224 +       if (!systick.dev.irq)
 225 +               panic("%s: request_irq failed", np->name);
 226 +
 227 +       clockevents_register_device(&systick.dev);
 228 +
 229 +       pr_info("%s: runing - mult: %d, shift: %d\n", np->name, systick.dev.mult, systick.dev.shift);
 230 +}
 231 +
 232 +CLOCKSOURCE_OF_DECLARE(systick, "ralink,cevt-systick", ralink_systick_init);