1 /* 2 * 3 * Utility functions for the Freescale MPC52xx. 4 * 5 * Copyright (C) 2006 Sylvain Munaut <tnt@246tNt.com> 6 * 7 * This file is licensed under the terms of the GNU General Public License 8 * version 2. This program is licensed "as is" without any warranty of any 9 * kind, whether express or implied. 10 * 11 */ 12 13 #undef DEBUG 14 15 #include <linux/kernel.h> 16 #include <linux/spinlock.h> 17 #include <linux/of_platform.h> 18 #include <asm/io.h> 19 #include <asm/prom.h> 20 #include <asm/mpc52xx.h> 21 22 /* MPC5200 device tree match tables */ 23 static struct of_device_id mpc52xx_xlb_ids[] __initdata = { 24 { .compatible = "fsl,mpc5200-xlb", }, 25 { .compatible = "mpc5200-xlb", }, 26 {} 27 }; 28 static struct of_device_id mpc52xx_bus_ids[] __initdata = { 29 { .compatible = "fsl,mpc5200-immr", }, 30 { .compatible = "fsl,mpc5200b-immr", }, 31 { .compatible = "simple-bus", }, 32 33 /* depreciated matches; shouldn't be used in new device trees */ 34 { .compatible = "fsl,lpb", }, 35 { .type = "builtin", .compatible = "mpc5200", }, /* efika */ 36 { .type = "soc", .compatible = "mpc5200", }, /* lite5200 */ 37 {} 38 }; 39 40 /* 41 * This variable is mapped in mpc52xx_map_wdt() and used in mpc52xx_restart(). 42 * Permanent mapping is required because mpc52xx_restart() can be called 43 * from interrupt context while node mapping (which calls ioremap()) 44 * cannot be used at such point. 45 */ 46 static DEFINE_SPINLOCK(mpc52xx_lock); 47 static struct mpc52xx_gpt __iomem *mpc52xx_wdt; 48 static struct mpc52xx_cdm __iomem *mpc52xx_cdm; 49 50 /** 51 * mpc52xx_find_ipb_freq - Find the IPB bus frequency for a device 52 * @node: device node 53 * 54 * Returns IPB bus frequency, or 0 if the bus frequency cannot be found. 55 */ 56 unsigned int 57 mpc52xx_find_ipb_freq(struct device_node *node) 58 { 59 struct device_node *np; 60 const unsigned int *p_ipb_freq = NULL; 61 62 of_node_get(node); 63 while (node) { 64 p_ipb_freq = of_get_property(node, "bus-frequency", NULL); 65 if (p_ipb_freq) 66 break; 67 68 np = of_get_parent(node); 69 of_node_put(node); 70 node = np; 71 } 72 if (node) 73 of_node_put(node); 74 75 return p_ipb_freq ? *p_ipb_freq : 0; 76 } 77 EXPORT_SYMBOL(mpc52xx_find_ipb_freq); 78 79 80 /* 81 * Configure the XLB arbiter settings to match what Linux expects. 82 */ 83 void __init 84 mpc5200_setup_xlb_arbiter(void) 85 { 86 struct device_node *np; 87 struct mpc52xx_xlb __iomem *xlb; 88 89 np = of_find_matching_node(NULL, mpc52xx_xlb_ids); 90 xlb = of_iomap(np, 0); 91 of_node_put(np); 92 if (!xlb) { 93 printk(KERN_ERR __FILE__ ": " 94 "Error mapping XLB in mpc52xx_setup_cpu(). " 95 "Expect some abnormal behavior\n"); 96 return; 97 } 98 99 /* Configure the XLB Arbiter priorities */ 100 out_be32(&xlb->master_pri_enable, 0xff); 101 out_be32(&xlb->master_priority, 0x11111111); 102 103 /* 104 * Disable XLB pipelining 105 * (cfr errate 292. We could do this only just before ATA PIO 106 * transaction and re-enable it afterwards ...) 107 * Not needed on MPC5200B. 108 */ 109 if ((mfspr(SPRN_SVR) & MPC5200_SVR_MASK) == MPC5200_SVR) 110 out_be32(&xlb->config, in_be32(&xlb->config) | MPC52xx_XLB_CFG_PLDIS); 111 112 iounmap(xlb); 113 } 114 115 /** 116 * mpc52xx_declare_of_platform_devices: register internal devices and children 117 * of the localplus bus to the of_platform 118 * bus. 119 */ 120 void __init 121 mpc52xx_declare_of_platform_devices(void) 122 { 123 /* Find every child of the SOC node and add it to of_platform */ 124 if (of_platform_bus_probe(NULL, mpc52xx_bus_ids, NULL)) 125 printk(KERN_ERR __FILE__ ": " 126 "Error while probing of_platform bus\n"); 127 } 128 129 /* 130 * match tables used by mpc52xx_map_common_devices() 131 */ 132 static struct of_device_id mpc52xx_gpt_ids[] __initdata = { 133 { .compatible = "fsl,mpc5200-gpt", }, 134 { .compatible = "mpc5200-gpt", }, /* old */ 135 {} 136 }; 137 static struct of_device_id mpc52xx_cdm_ids[] __initdata = { 138 { .compatible = "fsl,mpc5200-cdm", }, 139 { .compatible = "mpc5200-cdm", }, /* old */ 140 {} 141 }; 142 143 /** 144 * mpc52xx_map_common_devices: iomap devices required by common code 145 */ 146 void __init 147 mpc52xx_map_common_devices(void) 148 { 149 struct device_node *np; 150 151 /* mpc52xx_wdt is mapped here and used in mpc52xx_restart, 152 * possibly from a interrupt context. wdt is only implement 153 * on a gpt0, so check has-wdt property before mapping. 154 */ 155 for_each_matching_node(np, mpc52xx_gpt_ids) { 156 if (of_get_property(np, "fsl,has-wdt", NULL) || 157 of_get_property(np, "has-wdt", NULL)) { 158 mpc52xx_wdt = of_iomap(np, 0); 159 of_node_put(np); 160 break; 161 } 162 } 163 164 /* Clock Distribution Module, used by PSC clock setting function */ 165 np = of_find_matching_node(NULL, mpc52xx_cdm_ids); 166 mpc52xx_cdm = of_iomap(np, 0); 167 of_node_put(np); 168 } 169 170 /** 171 * mpc52xx_set_psc_clkdiv: Set clock divider in the CDM for PSC ports 172 * 173 * @psc_id: id of psc port; must be 1,2,3 or 6 174 * @clkdiv: clock divider value to put into CDM PSC register. 175 */ 176 int mpc52xx_set_psc_clkdiv(int psc_id, int clkdiv) 177 { 178 unsigned long flags; 179 u16 __iomem *reg; 180 u32 val; 181 u32 mask; 182 u32 mclken_div; 183 184 if (!mpc52xx_cdm) 185 return -ENODEV; 186 187 mclken_div = 0x8000 | (clkdiv & 0x1FF); 188 switch (psc_id) { 189 case 1: reg = &mpc52xx_cdm->mclken_div_psc1; mask = 0x20; break; 190 case 2: reg = &mpc52xx_cdm->mclken_div_psc2; mask = 0x40; break; 191 case 3: reg = &mpc52xx_cdm->mclken_div_psc3; mask = 0x80; break; 192 case 6: reg = &mpc52xx_cdm->mclken_div_psc6; mask = 0x10; break; 193 default: 194 return -ENODEV; 195 } 196 197 /* Set the rate and enable the clock */ 198 spin_lock_irqsave(&mpc52xx_lock, flags); 199 out_be16(reg, mclken_div); 200 val = in_be32(&mpc52xx_cdm->clk_enables); 201 out_be32(&mpc52xx_cdm->clk_enables, val | mask); 202 spin_unlock_irqrestore(&mpc52xx_lock, flags); 203 204 return 0; 205 } 206 EXPORT_SYMBOL(mpc52xx_set_psc_clkdiv); 207 208 /** 209 * mpc52xx_get_xtal_freq - Get SYS_XTAL_IN frequency for a device 210 * 211 * @node: device node 212 * 213 * Returns the frequency of the external oscillator clock connected 214 * to the SYS_XTAL_IN pin, or 0 if it cannot be determined. 215 */ 216 unsigned int mpc52xx_get_xtal_freq(struct device_node *node) 217 { 218 u32 val; 219 unsigned int freq; 220 221 if (!mpc52xx_cdm) 222 return 0; 223 224 freq = mpc52xx_find_ipb_freq(node); 225 if (!freq) 226 return 0; 227 228 if (in_8(&mpc52xx_cdm->ipb_clk_sel) & 0x1) 229 freq *= 2; 230 231 val = in_be32(&mpc52xx_cdm->rstcfg); 232 if (val & (1 << 5)) 233 freq *= 8; 234 else 235 freq *= 4; 236 if (val & (1 << 6)) 237 freq /= 12; 238 else 239 freq /= 16; 240 241 return freq; 242 } 243 EXPORT_SYMBOL(mpc52xx_get_xtal_freq); 244 245 /** 246 * mpc52xx_restart: ppc_md->restart hook for mpc5200 using the watchdog timer 247 */ 248 void 249 mpc52xx_restart(char *cmd) 250 { 251 local_irq_disable(); 252 253 /* Turn on the watchdog and wait for it to expire. 254 * It effectively does a reset. */ 255 if (mpc52xx_wdt) { 256 out_be32(&mpc52xx_wdt->mode, 0x00000000); 257 out_be32(&mpc52xx_wdt->count, 0x000000ff); 258 out_be32(&mpc52xx_wdt->mode, 0x00009004); 259 } else 260 printk(KERN_ERR __FILE__ ": " 261 "mpc52xx_restart: Can't access wdt. " 262 "Restart impossible, system halted.\n"); 263 264 while (1); 265 } 266