arch/arm/mach-at91/arm926ejs/clock.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * [origin: Linux kernel linux/arch/arm/mach-at91/clock.c]
   4  *
   5  * Copyright (C) 2005 David Brownell
   6  * Copyright (C) 2005 Ivan Kokshaysky
   7  * Copyright (C) 2009 Jean-Christophe PLAGNIOL-VILLARD <[email protected]>
   8  */
   9
  10 #include <common.h>
  11 #include <asm/global_data.h>
  12 #include <asm/io.h>
  13 #include <asm/arch/hardware.h>
  14 #include <asm/arch/at91_pmc.h>
  15 #include <asm/arch/clk.h>
  16
  17 #if !defined(CONFIG_AT91FAMILY)
  18 # error You need to define CONFIG_AT91FAMILY in your board config!
  19 #endif
  20
  21 #define EN_PLLB_TIMEOUT 500
  22
  23 DECLARE_GLOBAL_DATA_PTR;
  24
  25 static unsigned long at91_css_to_rate(unsigned long css)
  26 {
  27         switch (css) {
  28         case AT91_PMC_MCKR_CSS_SLOW:
  29                 return CFG_SYS_AT91_SLOW_CLOCK;
  30         case AT91_PMC_MCKR_CSS_MAIN:
  31                 return gd->arch.main_clk_rate_hz;
  32         case AT91_PMC_MCKR_CSS_PLLA:
  33                 return gd->arch.plla_rate_hz;
  34         case AT91_PMC_MCKR_CSS_PLLB:
  35                 return gd->arch.pllb_rate_hz;
  36         }
  37
  38         return 0;
  39 }
  40
  41 #ifdef CONFIG_USB_ATMEL
  42 static unsigned at91_pll_calc(unsigned main_freq, unsigned out_freq)
  43 {
  44         unsigned i, div = 0, mul = 0, diff = 1 << 30;
  45         unsigned ret = (out_freq > 155000000) ? 0xbe00 : 0x3e00;
  46
  47         /* PLL output max 240 MHz (or 180 MHz per errata) */
  48         if (out_freq > 240000000)
  49                 goto fail;
  50
  51         for (i = 1; i < 256; i++) {
  52                 int diff1;
  53                 unsigned input, mul1;
  54
  55                 /*
  56                  * PLL input between 1MHz and 32MHz per spec, but lower
  57                  * frequences seem necessary in some cases so allow 100K.
  58                  * Warning: some newer products need 2MHz min.
  59                  */
  60                 input = main_freq / i;
  61 #if defined(CONFIG_AT91SAM9G20)
  62                 if (input < 2000000)
  63                         continue;
  64 #endif
  65                 if (input < 100000)
  66                         continue;
  67                 if (input > 32000000)
  68                         continue;
  69
  70                 mul1 = out_freq / input;
  71 #if defined(CONFIG_AT91SAM9G20)
  72                 if (mul > 63)
  73                         continue;
  74 #endif
  75                 if (mul1 > 2048)
  76                         continue;
  77                 if (mul1 < 2)
  78                         goto fail;
  79
  80                 diff1 = out_freq - input * mul1;
  81                 if (diff1 < 0)
  82                         diff1 = -diff1;
  83                 if (diff > diff1) {
  84                         diff = diff1;
  85                         div = i;
  86                         mul = mul1;
  87                         if (diff == 0)
  88                                 break;
  89                 }
  90         }
  91         if (i == 256 && diff > (out_freq >> 5))
  92                 goto fail;
  93         return ret | ((mul - 1) << 16) | div;
  94 fail:
  95         return 0;
  96 }
  97 #endif
  98
  99 static u32 at91_pll_rate(u32 freq, u32 reg)
 100 {
 101         unsigned mul, div;
 102
 103         div = reg & 0xff;
 104         mul = (reg >> 16) & 0x7ff;
 105         if (div && mul) {
 106                 freq /= div;
 107                 freq *= mul + 1;
 108         } else
 109                 freq = 0;
 110
 111         return freq;
 112 }
 113
 114 int at91_clock_init(unsigned long main_clock)
 115 {
 116         unsigned freq, mckr;
 117         at91_pmc_t *pmc = (at91_pmc_t *) ATMEL_BASE_PMC;
 118 #ifndef CFG_SYS_AT91_MAIN_CLOCK
 119         unsigned tmp;
 120         /*
 121          * When the bootloader initialized the main oscillator correctly,
 122          * there's no problem using the cycle counter.  But if it didn't,
 123          * or when using oscillator bypass mode, we must be told the speed
 124          * of the main clock.
 125          */
 126         if (!main_clock) {
 127                 do {
 128                         tmp = readl(&pmc->mcfr);
 129                 } while (!(tmp & AT91_PMC_MCFR_MAINRDY));
 130                 tmp &= AT91_PMC_MCFR_MAINF_MASK;
 131                 main_clock = tmp * (CFG_SYS_AT91_SLOW_CLOCK / 16);
 132         }
 133 #endif
 134         gd->arch.main_clk_rate_hz = main_clock;
 135
 136         /* report if PLLA is more than mildly overclocked */
 137         gd->arch.plla_rate_hz = at91_pll_rate(main_clock, readl(&pmc->pllar));
 138
 139 #ifdef CONFIG_USB_ATMEL
 140         /*
 141          * USB clock init:  choose 48 MHz PLLB value,
 142          * disable 48MHz clock during usb peripheral suspend.
 143          *
 144          * REVISIT:  assumes MCK doesn't derive from PLLB!
 145          */
 146         gd->arch.at91_pllb_usb_init = at91_pll_calc(main_clock, 48000000 * 2) |
 147                              AT91_PMC_PLLBR_USBDIV_2;
 148         gd->arch.pllb_rate_hz = at91_pll_rate(main_clock,
 149                                               gd->arch.at91_pllb_usb_init);
 150 #endif
 151
 152         /*
 153          * MCK and CPU derive from one of those primary clocks.
 154          * For now, assume this parentage won't change.
 155          */
 156         mckr = readl(&pmc->mckr);
 157 #if defined(CONFIG_AT91SAM9G45) || defined(CONFIG_AT91SAM9M10G45) \
 158                 || defined(CONFIG_AT91SAM9N12) || defined(CONFIG_AT91SAM9X5)
 159         /* plla divisor by 2 */
 160         gd->arch.plla_rate_hz /= (1 << ((mckr & 1 << 12) >> 12));
 161 #endif
 162         gd->arch.mck_rate_hz = at91_css_to_rate(mckr & AT91_PMC_MCKR_CSS_MASK);
 163         freq = gd->arch.mck_rate_hz;
 164
 165 #if defined(CONFIG_AT91SAM9X5)
 166         /* different in prescale on at91sam9x5 */
 167         freq /= (1 << ((mckr & AT91_PMC_MCKR_PRES_MASK) >> 4));
 168 #else
 169         freq /= (1 << ((mckr & AT91_PMC_MCKR_PRES_MASK) >> 2)); /* prescale */
 170 #endif
 171
 172 #if defined(CONFIG_AT91SAM9G20)
 173         /* mdiv ; (x >> 7) = ((x >> 8) * 2) */
 174         gd->arch.mck_rate_hz = (mckr & AT91_PMC_MCKR_MDIV_MASK) ?
 175                 freq / ((mckr & AT91_PMC_MCKR_MDIV_MASK) >> 7) : freq;
 176         if (mckr & AT91_PMC_MCKR_MDIV_MASK)
 177                 freq /= 2;                      /* processor clock division */
 178 #elif defined(CONFIG_AT91SAM9G45) || defined(CONFIG_AT91SAM9M10G45) \
 179                 || defined(CONFIG_AT91SAM9N12) || defined(CONFIG_AT91SAM9X5)
 180         /* mdiv <==> divisor
 181          *  0   <==>   1
 182          *  1   <==>   2
 183          *  2   <==>   4
 184          *  3   <==>   3
 185          */
 186         gd->arch.mck_rate_hz = (mckr & AT91_PMC_MCKR_MDIV_MASK) ==
 187                 (AT91_PMC_MCKR_MDIV_2 | AT91_PMC_MCKR_MDIV_4)
 188                 ? freq / 3
 189                 : freq / (1 << ((mckr & AT91_PMC_MCKR_MDIV_MASK) >> 8));
 190 #else
 191         gd->arch.mck_rate_hz = freq /
 192                         (1 << ((mckr & AT91_PMC_MCKR_MDIV_MASK) >> 8));
 193 #endif
 194         gd->arch.cpu_clk_rate_hz = freq;
 195
 196         return 0;
 197 }
 198
 199 #if !defined(AT91_PLL_LOCK_TIMEOUT)
 200 #define AT91_PLL_LOCK_TIMEOUT   1000000
 201 #endif
 202
 203 void at91_plla_init(u32 pllar)
 204 {
 205         struct at91_pmc *pmc = (struct at91_pmc *)ATMEL_BASE_PMC;
 206
 207         writel(pllar, &pmc->pllar);
 208         while (!(readl(&pmc->sr) & AT91_PMC_LOCKA))
 209                 ;
 210 }
 211 void at91_pllb_init(u32 pllbr)
 212 {
 213         struct at91_pmc *pmc = (struct at91_pmc *)ATMEL_BASE_PMC;
 214
 215         writel(pllbr, &pmc->pllbr);
 216         while (!(readl(&pmc->sr) & AT91_PMC_LOCKB))
 217                 ;
 218 }
 219
 220 void at91_mck_init(u32 mckr)
 221 {
 222         struct at91_pmc *pmc = (struct at91_pmc *)ATMEL_BASE_PMC;
 223         u32 tmp;
 224
 225         tmp = readl(&pmc->mckr);
 226         tmp &= ~AT91_PMC_MCKR_PRES_MASK;
 227         tmp |= mckr & AT91_PMC_MCKR_PRES_MASK;
 228         writel(tmp, &pmc->mckr);
 229         while (!(readl(&pmc->sr) & AT91_PMC_MCKRDY))
 230                 ;
 231
 232         tmp = readl(&pmc->mckr);
 233         tmp &= ~AT91_PMC_MCKR_MDIV_MASK;
 234         tmp |= mckr & AT91_PMC_MCKR_MDIV_MASK;
 235         writel(tmp, &pmc->mckr);
 236         while (!(readl(&pmc->sr) & AT91_PMC_MCKRDY))
 237                 ;
 238
 239         tmp = readl(&pmc->mckr);
 240         tmp &= ~AT91_PMC_MCKR_PLLADIV_MASK;
 241         tmp |= mckr & AT91_PMC_MCKR_PLLADIV_MASK;
 242         writel(tmp, &pmc->mckr);
 243         while (!(readl(&pmc->sr) & AT91_PMC_MCKRDY))
 244                 ;
 245
 246         tmp = readl(&pmc->mckr);
 247         tmp &= ~AT91_PMC_MCKR_CSS_MASK;
 248         tmp |= mckr & AT91_PMC_MCKR_CSS_MASK;
 249         writel(tmp, &pmc->mckr);
 250         while (!(readl(&pmc->sr) & AT91_PMC_MCKRDY))
 251                 ;
 252 }
 253
 254 int at91_pllb_clk_enable(u32 pllbr)
 255 {
 256         struct at91_pmc *pmc = (at91_pmc_t *)ATMEL_BASE_PMC;
 257         ulong start_time, tmp_time;
 258
 259         start_time = get_timer(0);
 260         writel(pllbr, &pmc->pllbr);
 261         while ((readl(&pmc->sr) & AT91_PMC_LOCKB) != AT91_PMC_LOCKB) {
 262                 tmp_time = get_timer(0);
 263                 if ((tmp_time - start_time) > EN_PLLB_TIMEOUT) {
 264                         printf("ERROR: failed to enable PLLB\n");
 265                         return -1;
 266                 }
 267         }
 268
 269         return 0;
 270 }
 271
 272 int at91_pllb_clk_disable(void)
 273 {
 274         struct at91_pmc *pmc = (at91_pmc_t *)ATMEL_BASE_PMC;
 275         ulong start_time, tmp_time;
 276
 277         start_time = get_timer(0);
 278         writel(0, &pmc->pllbr);
 279         while ((readl(&pmc->sr) & AT91_PMC_LOCKB) != 0) {
 280                 tmp_time = get_timer(0);
 281                 if ((tmp_time - start_time) > EN_PLLB_TIMEOUT) {
 282                         printf("ERROR: failed to disable PLLB\n");
 283                         return -1;
 284                 }
 285         }
 286
 287         return 0;
 288 }