1 /* 2 * CAN bus driver for the Freescale MPC5xxx embedded CPU. 3 * 4 * Copyright (C) 2004-2005 Andrey Volkov <avolkov@varma-el.com>, 5 * Varma Electronics Oy 6 * Copyright (C) 2008-2009 Wolfgang Grandegger <wg@grandegger.com> 7 * Copyright (C) 2009 Wolfram Sang, Pengutronix <w.sang@pengutronix.de> 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the version 2 of the GNU General Public License 11 * as published by the Free Software Foundation 12 * 13 * This program is distributed in the hope that it will be useful, but 14 * WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 * 18 * You should have received a copy of the GNU General Public License 19 * along with this program; if not, write to the Free Software 20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 21 */ 22 23 #include <linux/kernel.h> 24 #include <linux/module.h> 25 #include <linux/interrupt.h> 26 #include <linux/platform_device.h> 27 #include <linux/netdevice.h> 28 #include <linux/can.h> 29 #include <linux/can/dev.h> 30 #include <linux/of_platform.h> 31 #include <sysdev/fsl_soc.h> 32 #include <linux/io.h> 33 #include <asm/mpc52xx.h> 34 35 #include "mscan.h" 36 37 #define DRV_NAME "mpc5xxx_can" 38 39 static struct of_device_id mpc52xx_cdm_ids[] __devinitdata = { 40 { .compatible = "fsl,mpc5200-cdm", }, 41 {} 42 }; 43 44 /* 45 * Get frequency of the MSCAN clock source 46 * 47 * Either the oscillator clock (SYS_XTAL_IN) or the IP bus clock (IP_CLK) 48 * can be selected. According to the MPC5200 user's manual, the oscillator 49 * clock is the better choice as it has less jitter but due to a hardware 50 * bug, it can not be selected for the old MPC5200 Rev. A chips. 51 */ 52 53 static unsigned int __devinit mpc52xx_can_clock_freq(struct of_device *of, 54 int clock_src) 55 { 56 unsigned int pvr; 57 struct mpc52xx_cdm __iomem *cdm; 58 struct device_node *np_cdm; 59 unsigned int freq; 60 u32 val; 61 62 pvr = mfspr(SPRN_PVR); 63 64 freq = mpc5xxx_get_bus_frequency(of->node); 65 if (!freq) 66 return 0; 67 68 if (clock_src == MSCAN_CLKSRC_BUS || pvr == 0x80822011) 69 return freq; 70 71 /* Determine SYS_XTAL_IN frequency from the clock domain settings */ 72 np_cdm = of_find_matching_node(NULL, mpc52xx_cdm_ids); 73 if (!np_cdm) { 74 dev_err(&of->dev, "can't get clock node!\n"); 75 return 0; 76 } 77 cdm = of_iomap(np_cdm, 0); 78 of_node_put(np_cdm); 79 80 if (in_8(&cdm->ipb_clk_sel) & 0x1) 81 freq *= 2; 82 val = in_be32(&cdm->rstcfg); 83 84 freq *= (val & (1 << 5)) ? 8 : 4; 85 freq /= (val & (1 << 6)) ? 12 : 16; 86 87 iounmap(cdm); 88 89 return freq; 90 } 91 92 static int __devinit mpc5xxx_can_probe(struct of_device *ofdev, 93 const struct of_device_id *id) 94 { 95 struct device_node *np = ofdev->node; 96 struct net_device *dev; 97 struct mscan_priv *priv; 98 void __iomem *base; 99 const char *clk_src; 100 int err, irq, clock_src; 101 102 base = of_iomap(ofdev->node, 0); 103 if (!base) { 104 dev_err(&ofdev->dev, "couldn't ioremap\n"); 105 err = -ENOMEM; 106 goto exit_release_mem; 107 } 108 109 irq = irq_of_parse_and_map(np, 0); 110 if (!irq) { 111 dev_err(&ofdev->dev, "no irq found\n"); 112 err = -ENODEV; 113 goto exit_unmap_mem; 114 } 115 116 dev = alloc_mscandev(); 117 if (!dev) { 118 err = -ENOMEM; 119 goto exit_dispose_irq; 120 } 121 122 priv = netdev_priv(dev); 123 priv->reg_base = base; 124 dev->irq = irq; 125 126 /* 127 * Either the oscillator clock (SYS_XTAL_IN) or the IP bus clock 128 * (IP_CLK) can be selected as MSCAN clock source. According to 129 * the MPC5200 user's manual, the oscillator clock is the better 130 * choice as it has less jitter. For this reason, it is selected 131 * by default. 132 */ 133 clk_src = of_get_property(np, "fsl,mscan-clock-source", NULL); 134 if (clk_src && strcmp(clk_src, "ip") == 0) 135 clock_src = MSCAN_CLKSRC_BUS; 136 else 137 clock_src = MSCAN_CLKSRC_XTAL; 138 priv->can.clock.freq = mpc52xx_can_clock_freq(ofdev, clock_src); 139 if (!priv->can.clock.freq) { 140 dev_err(&ofdev->dev, "couldn't get MSCAN clock frequency\n"); 141 err = -ENODEV; 142 goto exit_free_mscan; 143 } 144 145 SET_NETDEV_DEV(dev, &ofdev->dev); 146 147 err = register_mscandev(dev, clock_src); 148 if (err) { 149 dev_err(&ofdev->dev, "registering %s failed (err=%d)\n", 150 DRV_NAME, err); 151 goto exit_free_mscan; 152 } 153 154 dev_set_drvdata(&ofdev->dev, dev); 155 156 dev_info(&ofdev->dev, "MSCAN at 0x%p, irq %d, clock %d Hz\n", 157 priv->reg_base, dev->irq, priv->can.clock.freq); 158 159 return 0; 160 161 exit_free_mscan: 162 free_candev(dev); 163 exit_dispose_irq: 164 irq_dispose_mapping(irq); 165 exit_unmap_mem: 166 iounmap(base); 167 exit_release_mem: 168 return err; 169 } 170 171 static int __devexit mpc5xxx_can_remove(struct of_device *ofdev) 172 { 173 struct net_device *dev = dev_get_drvdata(&ofdev->dev); 174 struct mscan_priv *priv = netdev_priv(dev); 175 176 dev_set_drvdata(&ofdev->dev, NULL); 177 178 unregister_mscandev(dev); 179 iounmap(priv->reg_base); 180 irq_dispose_mapping(dev->irq); 181 free_candev(dev); 182 183 return 0; 184 } 185 186 #ifdef CONFIG_PM 187 static struct mscan_regs saved_regs; 188 static int mpc5xxx_can_suspend(struct of_device *ofdev, pm_message_t state) 189 { 190 struct net_device *dev = dev_get_drvdata(&ofdev->dev); 191 struct mscan_priv *priv = netdev_priv(dev); 192 struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base; 193 194 _memcpy_fromio(&saved_regs, regs, sizeof(*regs)); 195 196 return 0; 197 } 198 199 static int mpc5xxx_can_resume(struct of_device *ofdev) 200 { 201 struct net_device *dev = dev_get_drvdata(&ofdev->dev); 202 struct mscan_priv *priv = netdev_priv(dev); 203 struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base; 204 205 regs->canctl0 |= MSCAN_INITRQ; 206 while (!(regs->canctl1 & MSCAN_INITAK)) 207 udelay(10); 208 209 regs->canctl1 = saved_regs.canctl1; 210 regs->canbtr0 = saved_regs.canbtr0; 211 regs->canbtr1 = saved_regs.canbtr1; 212 regs->canidac = saved_regs.canidac; 213 214 /* restore masks, buffers etc. */ 215 _memcpy_toio(®s->canidar1_0, (void *)&saved_regs.canidar1_0, 216 sizeof(*regs) - offsetof(struct mscan_regs, canidar1_0)); 217 218 regs->canctl0 &= ~MSCAN_INITRQ; 219 regs->cantbsel = saved_regs.cantbsel; 220 regs->canrier = saved_regs.canrier; 221 regs->cantier = saved_regs.cantier; 222 regs->canctl0 = saved_regs.canctl0; 223 224 return 0; 225 } 226 #endif 227 228 static struct of_device_id __devinitdata mpc5xxx_can_table[] = { 229 {.compatible = "fsl,mpc5200-mscan"}, 230 {}, 231 }; 232 233 static struct of_platform_driver mpc5xxx_can_driver = { 234 .owner = THIS_MODULE, 235 .name = "mpc5xxx_can", 236 .probe = mpc5xxx_can_probe, 237 .remove = __devexit_p(mpc5xxx_can_remove), 238 #ifdef CONFIG_PM 239 .suspend = mpc5xxx_can_suspend, 240 .resume = mpc5xxx_can_resume, 241 #endif 242 .match_table = mpc5xxx_can_table, 243 }; 244 245 static int __init mpc5xxx_can_init(void) 246 { 247 return of_register_platform_driver(&mpc5xxx_can_driver); 248 } 249 module_init(mpc5xxx_can_init); 250 251 static void __exit mpc5xxx_can_exit(void) 252 { 253 return of_unregister_platform_driver(&mpc5xxx_can_driver); 254 }; 255 module_exit(mpc5xxx_can_exit); 256 257 MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>"); 258 MODULE_DESCRIPTION("Freescale MPC5200 CAN driver"); 259 MODULE_LICENSE("GPL v2"); 260