target/linux/ramips/patches-3.9/0142-clocksource-MIPS-ralink-add-support-for-systick-time.patch

   1 From bc350a91da176ae8573c0755c66f5ee1911495bc Mon Sep 17 00:00:00 2001
   2 From: John Crispin <blogic@openwrt.org>
   3 Date: Tue, 30 Apr 2013 12:35:50 +0200
   4 Subject: [PATCH 142/164] 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  include/linux/clocksource.h       |    1 +
  15  6 files changed, 173 insertions(+)
  16  create mode 100644 drivers/clocksource/cevt-rt3352.c
  17
  18 --- a/arch/mips/ralink/Kconfig
  19 +++ b/arch/mips/ralink/Kconfig
  20 @@ -14,6 +14,7 @@ choice
  21                 select USB_ARCH_HAS_HCD
  22                 select USB_ARCH_HAS_OHCI
  23                 select USB_ARCH_HAS_EHCI
  24 +               select CLKEVT_RT3352
  25
  26         config SOC_RT3883
  27                 bool "RT3883"
  28 @@ -22,6 +23,7 @@ choice
  29
  30         config SOC_MT7620
  31                 bool "MT7620"
  32 +               select CLKEVT_RT3352
  33
  34  endchoice
  35
  36 --- a/arch/mips/ralink/clk.c
  37 +++ b/arch/mips/ralink/clk.c
  38 @@ -69,4 +69,5 @@ void __init plat_time_init(void)
  39         pr_info("CPU Clock: %ldMHz\n", clk_get_rate(clk) / 1000000);
  40         mips_hpt_frequency = clk_get_rate(clk) / 2;
  41         clk_put(clk);
  42 +       clocksource_of_init();
  43  }
  44 --- a/drivers/clocksource/Kconfig
  45 +++ b/drivers/clocksource/Kconfig
  46 @@ -7,6 +7,12 @@ config CLKSRC_I8253
  47  config CLKEVT_I8253
  48         bool
  49
  50 +config CLKEVT_RT3352
  51 +       bool
  52 +       depends on MIPS && RALINK
  53 +       select CLKSRC_OF
  54 +       select CLKSRC_MMIO
  55 +
  56  config I8253_LOCK
  57         bool
  58
  59 --- a/drivers/clocksource/Makefile
  60 +++ b/drivers/clocksource/Makefile
  61 @@ -10,6 +10,7 @@ obj-$(CONFIG_SH_TIMER_TMU)    += sh_tmu.o
  62  obj-$(CONFIG_EM_TIMER_STI)     += em_sti.o
  63  obj-$(CONFIG_CLKBLD_I8253)     += i8253.o
  64  obj-$(CONFIG_CLKSRC_MMIO)      += mmio.o
  65 +obj-$(CONFIG_CLKEVT_RT3352)    += cevt-rt3352.o
  66  obj-$(CONFIG_DW_APB_TIMER)     += dw_apb_timer.o
  67  obj-$(CONFIG_DW_APB_TIMER_OF)  += dw_apb_timer_of.o
  68  obj-$(CONFIG_CLKSRC_NOMADIK_MTU)       += nomadik-mtu.o
  69 --- /dev/null
  70 +++ b/drivers/clocksource/cevt-rt3352.c
  71 @@ -0,0 +1,162 @@
  72 +/*
  73 + * This file is subject to the terms and conditions of the GNU General Public
  74 + * License.  See the file "COPYING" in the main directory of this archive
  75 + * for more details.
  76 + *
  77 + * Copyright (C) 2013 by John Crispin <blogic@openwrt.org>
  78 + */
  79 +
  80 +#include <linux/clockchips.h>
  81 +#include <linux/clocksource.h>
  82 +#include <linux/interrupt.h>
  83 +#include <linux/reset.h>
  84 +#include <linux/init.h>
  85 +#include <linux/of.h>
  86 +#include <linux/of_irq.h>
  87 +#include <linux/of_address.h>
  88 +
  89 +#include <asm/mach-ralink/ralink_regs.h>
  90 +#include <asm/time.h>
  91 +
  92 +#define SYSTICK_FREQ   (50 * 1000)
  93 +
  94 +#define SYSTICK_CONFIG 0x00
  95 +#define SYSTICK_COMPARE        0x04
  96 +#define SYSTICK_COUNT  0x08
  97 +
  98 +/* route systick irq to mips irq 7 instead of the r4k-timer */
  99 +#define CFG_EXT_STK_EN 0x2
 100 +/* enable the counter */
 101 +#define CFG_CNT_EN     0x1
 102 +
 103 +struct systick_device {
 104 +       void __iomem *membase;
 105 +       struct clock_event_device dev;
 106 +       int irq_requested;
 107 +       int freq_scale;
 108 +};
 109 +
 110 +static void systick_set_clock_mode(enum clock_event_mode mode,
 111 +                               struct clock_event_device *evt);
 112 +
 113 +static int systick_next_event(unsigned long delta,
 114 +                               struct clock_event_device *evt)
 115 +{
 116 +       struct systick_device *sdev = container_of(evt, struct systick_device, dev);
 117 +       u32 count;
 118 +
 119 +       count = ioread32(sdev->membase + SYSTICK_COUNT);
 120 +       count = (count + delta) % SYSTICK_FREQ;
 121 +       iowrite32(count + delta, sdev->membase + SYSTICK_COMPARE);
 122 +
 123 +       return 0;
 124 +}
 125 +
 126 +static void systick_event_handler(struct clock_event_device *dev)
 127 +{
 128 +       /* noting to do here */
 129 +}
 130 +
 131 +static irqreturn_t systick_interrupt(int irq, void *dev_id)
 132 +{
 133 +       struct clock_event_device *dev = (struct clock_event_device *) dev_id;
 134 +
 135 +       dev->event_handler(dev);
 136 +
 137 +       return IRQ_HANDLED;
 138 +}
 139 +
 140 +static struct systick_device systick = {
 141 +       .dev = {
 142 +               /* cevt-r4k uses 300, make sure systick gets used if available */
 143 +               .rating         = 310,
 144 +               .features       = CLOCK_EVT_FEAT_ONESHOT,
 145 +               .set_next_event = systick_next_event,
 146 +               .set_mode       = systick_set_clock_mode,
 147 +               .event_handler  = systick_event_handler,
 148 +       },
 149 +};
 150 +
 151 +static struct irqaction systick_irqaction = {
 152 +       .handler = systick_interrupt,
 153 +       .flags = IRQF_PERCPU | IRQF_TIMER,
 154 +       .dev_id = &systick.dev,
 155 +};
 156 +
 157 +/* ugly hack */
 158 +#ifdef CONFIG_SOC_MT7620
 159 +
 160 +#define CLK_LUT_CFG    0x40
 161 +#define SLEEP_EN       BIT(31)
 162 +
 163 +static inline void mt7620_freq_scaling(struct systick_device *sdev, int status)
 164 +{
 165 +       if (sdev->freq_scale == status)
 166 +               return;
 167 +
 168 +       sdev->freq_scale = status;
 169 +
 170 +       pr_info("%s: %s autosleep mode\n", systick.dev.name, (status) ? ("enable") : ("disable"));
 171 +       if (status)
 172 +               rt_sysc_w32(rt_sysc_r32(CLK_LUT_CFG) | SLEEP_EN, CLK_LUT_CFG);
 173 +       else
 174 +               rt_sysc_w32(rt_sysc_r32(CLK_LUT_CFG) & ~SLEEP_EN, CLK_LUT_CFG);
 175 +}
 176 +#else
 177 +static inline void mt7620_freq_scaling(struct systick_device *sdev, int status) {}
 178 +#endif
 179 +
 180 +static void systick_set_clock_mode(enum clock_event_mode mode,
 181 +                               struct clock_event_device *evt)
 182 +{
 183 +       struct systick_device *sdev = container_of(evt, struct systick_device, dev);
 184 +
 185 +       switch (mode) {
 186 +       case CLOCK_EVT_MODE_ONESHOT:
 187 +               if (!sdev->irq_requested)
 188 +                       setup_irq(systick.dev.irq, &systick_irqaction);
 189 +               mt7620_freq_scaling(sdev, 1);
 190 +               sdev->irq_requested = 1;
 191 +               iowrite32(CFG_EXT_STK_EN | CFG_CNT_EN, systick.membase + SYSTICK_CONFIG);
 192 +               break;
 193 +
 194 +       case CLOCK_EVT_MODE_SHUTDOWN:
 195 +               if (sdev->irq_requested)
 196 +                       free_irq(systick.dev.irq, &systick_irqaction);
 197 +               mt7620_freq_scaling(sdev, 0);
 198 +               sdev->irq_requested = 0;
 199 +               iowrite32(0, systick.membase + SYSTICK_CONFIG);
 200 +               break;
 201 +
 202 +       default:
 203 +               pr_err("%s: Unhandeled mips clock_mode\n", systick.dev.name);
 204 +               break;
 205 +       }
 206 +}
 207 +
 208 +static void __init ralink_systick_init(struct device_node *np)
 209 +{
 210 +       systick.membase = of_iomap(np, 0);
 211 +       if (!systick.membase) {
 212 +               pr_err("%s: of_iomap failed", np->name);
 213 +               return;
 214 +       }
 215 +
 216 +       clocksource_mmio_init(systick.membase + SYSTICK_COUNT, np->name,
 217 +                       SYSTICK_FREQ, 301, 16, clocksource_mmio_readl_up);
 218 +
 219 +       systick_irqaction.name = np->name;
 220 +       systick.dev.name = np->name;
 221 +       clockevent_set_clock(&systick.dev, SYSTICK_FREQ);
 222 +       systick.dev.max_delta_ns = clockevent_delta2ns(0x7fff, &systick.dev);
 223 +       systick.dev.min_delta_ns = clockevent_delta2ns(0x3, &systick.dev);
 224 +       systick.dev.irq = irq_of_parse_and_map(np, 0);
 225 +       if (!systick.dev.irq)
 226 +               panic("%s: request_irq failed", np->name);
 227 +
 228 +       clockevents_register_device(&systick.dev);
 229 +
 230 +       pr_info("%s: runing - mult: %d, shift: %d\n", np->name, systick.dev.mult, systick.dev.shift);
 231 +}
 232 +
 233 +CLOCKSOURCE_OF_DECLARE(systick, "ralink,cevt-systick", ralink_systick_init);
 234 --- a/include/linux/clocksource.h
 235 +++ b/include/linux/clocksource.h
 236 @@ -340,6 +340,7 @@ extern void clocksource_of_init(void);
 237                 __used __section(__clksrc_of_table)                     \
 238                  = { .compatible = compat, .data = fn };
 239  #else
 240 +static inline void clocksource_of_init(void) {}
 241  #define CLOCKSOURCE_OF_DECLARE(name, compat, fn)
 242  #endif
 243