/*
* ricoh_mmc.c - Dummy driver to disable the Rioch MMC controller.
*
* Copyright (C) 2007 Philip Langdale, All Rights Reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or (at
* your option) any later version.
*/
/*
* This is a conceptually ridiculous driver, but it is required by the way
* the Ricoh multi-function R5C832 works. This chip implements firewire
* and four different memory card controllers. Two of those controllers are
* an SDHCI controller and a proprietary MMC controller. The linux SDHCI
* driver supports MMC cards but the chip detects MMC cards in hardware
* and directs them to the MMC controller - so the SDHCI driver never sees
* them. To get around this, we must disable the useless MMC controller.
* At that point, the SDHCI controller will start seeing them. As a bonus,
* a detection event occurs immediately, even if the MMC card is already
* in the reader.
*
* The relevant registers live on the firewire function, so this is unavoidably
* ugly. Such is life.
*/
#include <linux/pci.h>
#define DRIVER_NAME "ricoh-mmc"
static const struct pci_device_id pci_ids[] __devinitdata = {
{
.vendor = PCI_VENDOR_ID_RICOH,
.device = PCI_DEVICE_ID_RICOH_R5C843,
.subvendor = PCI_ANY_ID,
.subdevice = PCI_ANY_ID,
},
{ /* end: all zeroes */ },
};
MODULE_DEVICE_TABLE(pci, pci_ids);
static int __devinit ricoh_mmc_probe(struct pci_dev *pdev,
const struct pci_device_id *ent)
{
u8 rev;
struct pci_dev *fw_dev = NULL;
BUG_ON(pdev == NULL);
BUG_ON(ent == NULL);
pci_read_config_byte(pdev, PCI_CLASS_REVISION, &rev);
printk(KERN_INFO DRIVER_NAME
": Ricoh MMC controller found at %s [%04x:%04x] (rev %x)\n",
pci_name(pdev), (int)pdev->vendor, (int)pdev->device,
(int)rev);
while ((fw_dev = pci_get_device(PCI_VENDOR_ID_RICOH, PCI_DEVICE_ID_RICOH_R5C832, fw_dev))) {
if (PCI_SLOT(pdev->devfn) == PCI_SLOT(fw_dev->devfn) &&
pdev->bus == fw_dev->bus) {
u8 write_enable;
u8 disable;
pci_read_config_byte(fw_dev, 0xCB, &disable);
if (disable & 0x02) {
printk(KERN_INFO DRIVER_NAME
": Controller already disabled. Nothing to do.\n");
return -ENODEV;
}
pci_read_config_byte(fw_dev, 0xCA, &write_enable);
pci_write_config_byte(fw_dev, 0xCA, 0x57);
pci_write_config_byte(fw_dev, 0xCB, disable | 0x02);
pci_write_config_byte(fw_dev, 0xCA, write_enable);
pci_set_drvdata(pdev, fw_dev);
printk(KERN_INFO DRIVER_NAME
": Controller is now disabled.\n");
break;
}
}
if (pci_get_drvdata(pdev) == NULL) {
printk(KERN_WARNING DRIVER_NAME
": Main firewire function not found. Cannot disable controller.\n");
return -ENODEV;
}
return 0;
}
static void __devexit ricoh_mmc_remove(struct pci_dev *pdev)
{
u8 write_enable;
u8 disable;
struct pci_dev *fw_dev = NULL;
fw_dev = pci_get_drvdata(pdev);
BUG_ON(fw_dev == NULL);
pci_read_config_byte(fw_dev, 0xCA, &write_enable);
pci_read_config_byte(fw_dev, 0xCB, &disable);
pci_write_config_byte(fw_dev, 0xCA, 0x57);
pci_write_config_byte(fw_dev, 0xCB, disable & ~0x02);
pci_write_config_byte(fw_dev, 0xCA, write_enable);
printk(KERN_INFO DRIVER_NAME
": Controller is now re-enabled.\n");
pci_set_drvdata(pdev, NULL);
}
static struct pci_driver ricoh_mmc_driver = {
.name = DRIVER_NAME,
.id_table = pci_ids,
.probe = ricoh_mmc_probe,
.remove = __devexit_p(ricoh_mmc_remove),
};
/*****************************************************************************\
* *
* Driver init/exit *
* *
\*****************************************************************************/
static int __init ricoh_mmc_drv_init(void)
{
printk(KERN_INFO DRIVER_NAME
": Ricoh MMC Controller disabling driver\n");
printk(KERN_INFO DRIVER_NAME ": Copyright(c) Philip Langdale\n");
return pci_register_driver(&ricoh_mmc_driver);
}
static void __exit ricoh_mmc_drv_exit(void)
{
pci_unregister_driver(&ricoh_mmc_driver);
}
module_init(ricoh_mmc_drv_init);
module_exit(ricoh_mmc_drv_exit);
MODULE_AUTHOR("Philip Langdale <philipl@alumni.utexas.net>");
MODULE_DESCRIPTION("Ricoh MMC Controller disabling driver");
MODULE_LICENSE("GPL");
