drivers/mmc/host/ricoh_mmc.c

   1 /*
   2  *  ricoh_mmc.c - Dummy driver to disable the Rioch MMC controller.
   3  *
   4  *  Copyright (C) 2007 Philip Langdale, All Rights Reserved.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or (at
   9  * your option) any later version.
  10  */
  11
  12 /*
  13  * This is a conceptually ridiculous driver, but it is required by the way
  14  * the Ricoh multi-function R5C832 works. This chip implements firewire
  15  * and four different memory card controllers. Two of those controllers are
  16  * an SDHCI controller and a proprietary MMC controller. The linux SDHCI
  17  * driver supports MMC cards but the chip detects MMC cards in hardware
  18  * and directs them to the MMC controller - so the SDHCI driver never sees
  19  * them. To get around this, we must disable the useless MMC controller.
  20  * At that point, the SDHCI controller will start seeing them. As a bonus,
  21  * a detection event occurs immediately, even if the MMC card is already
  22  * in the reader.
  23  *
  24  * The relevant registers live on the firewire function, so this is unavoidably
  25  * ugly. Such is life.
  26  */
  27
  28 #include <linux/pci.h>
  29
  30 #define DRIVER_NAME "ricoh-mmc"
  31
  32 static const struct pci_device_id pci_ids[] __devinitdata = {
  33         {
  34                 .vendor         = PCI_VENDOR_ID_RICOH,
  35                 .device         = PCI_DEVICE_ID_RICOH_R5C843,
  36                 .subvendor      = PCI_ANY_ID,
  37                 .subdevice      = PCI_ANY_ID,
  38         },
  39         { /* end: all zeroes */ },
  40 };
  41
  42 MODULE_DEVICE_TABLE(pci, pci_ids);
  43
  44 static int __devinit ricoh_mmc_probe(struct pci_dev *pdev,
  45                                      const struct pci_device_id *ent)
  46 {
  47         u8 rev;
  48
  49         struct pci_dev *fw_dev = NULL;
  50
  51         BUG_ON(pdev == NULL);
  52         BUG_ON(ent == NULL);
  53
  54         pci_read_config_byte(pdev, PCI_CLASS_REVISION, &rev);
  55
  56         printk(KERN_INFO DRIVER_NAME
  57                 ": Ricoh MMC controller found at %s [%04x:%04x] (rev %x)\n",
  58                 pci_name(pdev), (int)pdev->vendor, (int)pdev->device,
  59                 (int)rev);
  60
  61         while ((fw_dev = pci_get_device(PCI_VENDOR_ID_RICOH, PCI_DEVICE_ID_RICOH_R5C832, fw_dev))) {
  62                 if (PCI_SLOT(pdev->devfn) == PCI_SLOT(fw_dev->devfn) &&
  63                     pdev->bus == fw_dev->bus) {
  64                         u8 write_enable;
  65                         u8 disable;
  66
  67                         pci_read_config_byte(fw_dev, 0xCB, &disable);
  68                         if (disable & 0x02) {
  69                                 printk(KERN_INFO DRIVER_NAME
  70                                        ": Controller already disabled. Nothing to do.\n");
  71                                 return -ENODEV;
  72                         }
  73
  74                         pci_read_config_byte(fw_dev, 0xCA, &write_enable);
  75                         pci_write_config_byte(fw_dev, 0xCA, 0x57);
  76                         pci_write_config_byte(fw_dev, 0xCB, disable | 0x02);
  77                         pci_write_config_byte(fw_dev, 0xCA, write_enable);
  78
  79                         pci_set_drvdata(pdev, fw_dev);
  80
  81                         printk(KERN_INFO DRIVER_NAME
  82                                ": Controller is now disabled.\n");
  83
  84                         break;
  85                 }
  86         }
  87
  88         if (pci_get_drvdata(pdev) == NULL) {
  89                 printk(KERN_WARNING DRIVER_NAME
  90                        ": Main firewire function not found. Cannot disable controller.\n");
  91                 return -ENODEV;
  92         }
  93
  94         return 0;
  95 }
  96
  97 static void __devexit ricoh_mmc_remove(struct pci_dev *pdev)
  98 {
  99         u8 write_enable;
 100         u8 disable;
 101         struct pci_dev *fw_dev = NULL;
 102
 103         fw_dev = pci_get_drvdata(pdev);
 104         BUG_ON(fw_dev == NULL);
 105
 106         pci_read_config_byte(fw_dev, 0xCA, &write_enable);
 107         pci_read_config_byte(fw_dev, 0xCB, &disable);
 108         pci_write_config_byte(fw_dev, 0xCA, 0x57);
 109         pci_write_config_byte(fw_dev, 0xCB, disable & ~0x02);
 110         pci_write_config_byte(fw_dev, 0xCA, write_enable);
 111
 112         printk(KERN_INFO DRIVER_NAME
 113                ": Controller is now re-enabled.\n");
 114
 115         pci_set_drvdata(pdev, NULL);
 116 }
 117
 118 static struct pci_driver ricoh_mmc_driver = {
 119         .name =         DRIVER_NAME,
 120         .id_table =     pci_ids,
 121         .probe =        ricoh_mmc_probe,
 122         .remove =       __devexit_p(ricoh_mmc_remove),
 123 };
 124
 125 /*****************************************************************************\
 126  *                                                                           *
 127  * Driver init/exit                                                          *
 128  *                                                                           *
 129 \*****************************************************************************/
 130
 131 static int __init ricoh_mmc_drv_init(void)
 132 {
 133         printk(KERN_INFO DRIVER_NAME
 134                 ": Ricoh MMC Controller disabling driver\n");
 135         printk(KERN_INFO DRIVER_NAME ": Copyright(c) Philip Langdale\n");
 136
 137         return pci_register_driver(&ricoh_mmc_driver);
 138 }
 139
 140 static void __exit ricoh_mmc_drv_exit(void)
 141 {
 142         pci_unregister_driver(&ricoh_mmc_driver);
 143 }
 144
 145 module_init(ricoh_mmc_drv_init);
 146 module_exit(ricoh_mmc_drv_exit);
 147
 148 MODULE_AUTHOR("Philip Langdale <philipl@alumni.utexas.net>");
 149 MODULE_DESCRIPTION("Ricoh MMC Controller disabling driver");
 150 MODULE_LICENSE("GPL");
 151