arch/arm/mach-ep93xx/clock.c

   1 /*
   2  * arch/arm/mach-ep93xx/clock.c
   3  * Clock control for Cirrus EP93xx chips.
   4  *
   5  * Copyright (C) 2006 Lennert Buytenhek <buytenh@wantstofly.org>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or (at
  10  * your option) any later version.
  11  */
  12
  13 #include <linux/kernel.h>
  14 #include <linux/clk.h>
  15 #include <linux/err.h>
  16 #include <linux/module.h>
  17 #include <linux/string.h>
  18 #include <linux/io.h>
  19
  20 #include <asm/clkdev.h>
  21 #include <asm/div64.h>
  22 #include <mach/hardware.h>
  23
  24
  25 /*
  26  * The EP93xx has two external crystal oscillators.  To generate the
  27  * required high-frequency clocks, the processor uses two phase-locked-
  28  * loops (PLLs) to multiply the incoming external clock signal to much
  29  * higher frequencies that are then divided down by programmable dividers
  30  * to produce the needed clocks.  The PLLs operate independently of one
  31  * another.
  32  */
  33 #define EP93XX_EXT_CLK_RATE     14745600
  34 #define EP93XX_EXT_RTC_RATE     32768
  35
  36
  37 struct clk {
  38         unsigned long   rate;
  39         int             users;
  40         int             sw_locked;
  41         u32             enable_reg;
  42         u32             enable_mask;
  43
  44         unsigned long   (*get_rate)(struct clk *clk);
  45 };
  46
  47
  48 static unsigned long get_uart_rate(struct clk *clk);
  49
  50
  51 static struct clk clk_uart1 = {
  52         .sw_locked      = 1,
  53         .enable_reg     = EP93XX_SYSCON_DEVICE_CONFIG,
  54         .enable_mask    = EP93XX_SYSCON_DEVICE_CONFIG_U1EN,
  55         .get_rate       = get_uart_rate,
  56 };
  57 static struct clk clk_uart2 = {
  58         .sw_locked      = 1,
  59         .enable_reg     = EP93XX_SYSCON_DEVICE_CONFIG,
  60         .enable_mask    = EP93XX_SYSCON_DEVICE_CONFIG_U2EN,
  61         .get_rate       = get_uart_rate,
  62 };
  63 static struct clk clk_uart3 = {
  64         .sw_locked      = 1,
  65         .enable_reg     = EP93XX_SYSCON_DEVICE_CONFIG,
  66         .enable_mask    = EP93XX_SYSCON_DEVICE_CONFIG_U3EN,
  67         .get_rate       = get_uart_rate,
  68 };
  69 static struct clk clk_pll1;
  70 static struct clk clk_f;
  71 static struct clk clk_h;
  72 static struct clk clk_p;
  73 static struct clk clk_pll2;
  74 static struct clk clk_usb_host = {
  75         .enable_reg     = EP93XX_SYSCON_CLOCK_CONTROL,
  76         .enable_mask    = EP93XX_SYSCON_CLOCK_USH_EN,
  77 };
  78
  79 /* DMA Clocks */
  80 static struct clk clk_m2p0 = {
  81         .enable_reg     = EP93XX_SYSCON_CLOCK_CONTROL,
  82         .enable_mask    = 0x00020000,
  83 };
  84 static struct clk clk_m2p1 = {
  85         .enable_reg     = EP93XX_SYSCON_CLOCK_CONTROL,
  86         .enable_mask    = 0x00010000,
  87 };
  88 static struct clk clk_m2p2 = {
  89         .enable_reg     = EP93XX_SYSCON_CLOCK_CONTROL,
  90         .enable_mask    = 0x00080000,
  91 };
  92 static struct clk clk_m2p3 = {
  93         .enable_reg     = EP93XX_SYSCON_CLOCK_CONTROL,
  94         .enable_mask    = 0x00040000,
  95 };
  96 static struct clk clk_m2p4 = {
  97         .enable_reg     = EP93XX_SYSCON_CLOCK_CONTROL,
  98         .enable_mask    = 0x00200000,
  99 };
 100 static struct clk clk_m2p5 = {
 101         .enable_reg     = EP93XX_SYSCON_CLOCK_CONTROL,
 102         .enable_mask    = 0x00100000,
 103 };
 104 static struct clk clk_m2p6 = {
 105         .enable_reg     = EP93XX_SYSCON_CLOCK_CONTROL,
 106         .enable_mask    = 0x00800000,
 107 };
 108 static struct clk clk_m2p7 = {
 109         .enable_reg     = EP93XX_SYSCON_CLOCK_CONTROL,
 110         .enable_mask    = 0x00400000,
 111 };
 112 static struct clk clk_m2p8 = {
 113         .enable_reg     = EP93XX_SYSCON_CLOCK_CONTROL,
 114         .enable_mask    = 0x02000000,
 115 };
 116 static struct clk clk_m2p9 = {
 117         .enable_reg     = EP93XX_SYSCON_CLOCK_CONTROL,
 118         .enable_mask    = 0x01000000,
 119 };
 120 static struct clk clk_m2m0 = {
 121         .enable_reg     = EP93XX_SYSCON_CLOCK_CONTROL,
 122         .enable_mask    = 0x04000000,
 123 };
 124 static struct clk clk_m2m1 = {
 125         .enable_reg     = EP93XX_SYSCON_CLOCK_CONTROL,
 126         .enable_mask    = 0x08000000,
 127 };
 128
 129 #define INIT_CK(dev,con,ck)                                     \
 130         { .dev_id = dev, .con_id = con, .clk = ck }
 131
 132 static struct clk_lookup clocks[] = {
 133         INIT_CK("apb:uart1", NULL, &clk_uart1),
 134         INIT_CK("apb:uart2", NULL, &clk_uart2),
 135         INIT_CK("apb:uart3", NULL, &clk_uart3),
 136         INIT_CK(NULL, "pll1", &clk_pll1),
 137         INIT_CK(NULL, "fclk", &clk_f),
 138         INIT_CK(NULL, "hclk", &clk_h),
 139         INIT_CK(NULL, "pclk", &clk_p),
 140         INIT_CK(NULL, "pll2", &clk_pll2),
 141         INIT_CK(NULL, "usb_host", &clk_usb_host),
 142         INIT_CK(NULL, "m2p0", &clk_m2p0),
 143         INIT_CK(NULL, "m2p1", &clk_m2p1),
 144         INIT_CK(NULL, "m2p2", &clk_m2p2),
 145         INIT_CK(NULL, "m2p3", &clk_m2p3),
 146         INIT_CK(NULL, "m2p4", &clk_m2p4),
 147         INIT_CK(NULL, "m2p5", &clk_m2p5),
 148         INIT_CK(NULL, "m2p6", &clk_m2p6),
 149         INIT_CK(NULL, "m2p7", &clk_m2p7),
 150         INIT_CK(NULL, "m2p8", &clk_m2p8),
 151         INIT_CK(NULL, "m2p9", &clk_m2p9),
 152         INIT_CK(NULL, "m2m0", &clk_m2m0),
 153         INIT_CK(NULL, "m2m1", &clk_m2m1),
 154 };
 155
 156
 157 int clk_enable(struct clk *clk)
 158 {
 159         if (!clk->users++ && clk->enable_reg) {
 160                 u32 value;
 161
 162                 value = __raw_readl(clk->enable_reg);
 163                 if (clk->sw_locked)
 164                         __raw_writel(0xaa, EP93XX_SYSCON_SWLOCK);
 165                 __raw_writel(value | clk->enable_mask, clk->enable_reg);
 166         }
 167
 168         return 0;
 169 }
 170 EXPORT_SYMBOL(clk_enable);
 171
 172 void clk_disable(struct clk *clk)
 173 {
 174         if (!--clk->users && clk->enable_reg) {
 175                 u32 value;
 176
 177                 value = __raw_readl(clk->enable_reg);
 178                 if (clk->sw_locked)
 179                         __raw_writel(0xaa, EP93XX_SYSCON_SWLOCK);
 180                 __raw_writel(value & ~clk->enable_mask, clk->enable_reg);
 181         }
 182 }
 183 EXPORT_SYMBOL(clk_disable);
 184
 185 static unsigned long get_uart_rate(struct clk *clk)
 186 {
 187         u32 value;
 188
 189         value = __raw_readl(EP93XX_SYSCON_CLOCK_CONTROL);
 190         if (value & EP93XX_SYSCON_CLOCK_UARTBAUD)
 191                 return EP93XX_EXT_CLK_RATE;
 192         else
 193                 return EP93XX_EXT_CLK_RATE / 2;
 194 }
 195
 196 unsigned long clk_get_rate(struct clk *clk)
 197 {
 198         if (clk->get_rate)
 199                 return clk->get_rate(clk);
 200
 201         return clk->rate;
 202 }
 203 EXPORT_SYMBOL(clk_get_rate);
 204
 205
 206 static char fclk_divisors[] = { 1, 2, 4, 8, 16, 1, 1, 1 };
 207 static char hclk_divisors[] = { 1, 2, 4, 5, 6, 8, 16, 32 };
 208 static char pclk_divisors[] = { 1, 2, 4, 8 };
 209
 210 /*
 211  * PLL rate = 14.7456 MHz * (X1FBD + 1) * (X2FBD + 1) / (X2IPD + 1) / 2^PS
 212  */
 213 static unsigned long calc_pll_rate(u32 config_word)
 214 {
 215         unsigned long long rate;
 216         int i;
 217
 218         rate = EP93XX_EXT_CLK_RATE;
 219         rate *= ((config_word >> 11) & 0x1f) + 1;               /* X1FBD */
 220         rate *= ((config_word >> 5) & 0x3f) + 1;                /* X2FBD */
 221         do_div(rate, (config_word & 0x1f) + 1);                 /* X2IPD */
 222         for (i = 0; i < ((config_word >> 16) & 3); i++)         /* PS */
 223                 rate >>= 1;
 224
 225         return (unsigned long)rate;
 226 }
 227
 228 static void __init ep93xx_dma_clock_init(void)
 229 {
 230         clk_m2p0.rate = clk_h.rate;
 231         clk_m2p1.rate = clk_h.rate;
 232         clk_m2p2.rate = clk_h.rate;
 233         clk_m2p3.rate = clk_h.rate;
 234         clk_m2p4.rate = clk_h.rate;
 235         clk_m2p5.rate = clk_h.rate;
 236         clk_m2p6.rate = clk_h.rate;
 237         clk_m2p7.rate = clk_h.rate;
 238         clk_m2p8.rate = clk_h.rate;
 239         clk_m2p9.rate = clk_h.rate;
 240         clk_m2m0.rate = clk_h.rate;
 241         clk_m2m1.rate = clk_h.rate;
 242 }
 243
 244 static int __init ep93xx_clock_init(void)
 245 {
 246         u32 value;
 247         int i;
 248
 249         value = __raw_readl(EP93XX_SYSCON_CLOCK_SET1);
 250         if (!(value & 0x00800000)) {                    /* PLL1 bypassed?  */
 251                 clk_pll1.rate = EP93XX_EXT_CLK_RATE;
 252         } else {
 253                 clk_pll1.rate = calc_pll_rate(value);
 254         }
 255         clk_f.rate = clk_pll1.rate / fclk_divisors[(value >> 25) & 0x7];
 256         clk_h.rate = clk_pll1.rate / hclk_divisors[(value >> 20) & 0x7];
 257         clk_p.rate = clk_h.rate / pclk_divisors[(value >> 18) & 0x3];
 258         ep93xx_dma_clock_init();
 259
 260         value = __raw_readl(EP93XX_SYSCON_CLOCK_SET2);
 261         if (!(value & 0x00080000)) {                    /* PLL2 bypassed?  */
 262                 clk_pll2.rate = EP93XX_EXT_CLK_RATE;
 263         } else if (value & 0x00040000) {                /* PLL2 enabled?  */
 264                 clk_pll2.rate = calc_pll_rate(value);
 265         } else {
 266                 clk_pll2.rate = 0;
 267         }
 268         clk_usb_host.rate = clk_pll2.rate / (((value >> 28) & 0xf) + 1);
 269
 270         printk(KERN_INFO "ep93xx: PLL1 running at %ld MHz, PLL2 at %ld MHz\n",
 271                 clk_pll1.rate / 1000000, clk_pll2.rate / 1000000);
 272         printk(KERN_INFO "ep93xx: FCLK %ld MHz, HCLK %ld MHz, PCLK %ld MHz\n",
 273                 clk_f.rate / 1000000, clk_h.rate / 1000000,
 274                 clk_p.rate / 1000000);
 275
 276         for (i = 0; i < ARRAY_SIZE(clocks); i++)
 277                 clkdev_add(&clocks[i]);
 278         return 0;
 279 }
 280 arch_initcall(ep93xx_clock_init);