drivers/net/can/mscan/mpc52xx_can.c

   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(&regs->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");