diff options
Diffstat (limited to 'drivers/mmc/host/ricoh_mmc.c')
| -rw-r--r-- | drivers/mmc/host/ricoh_mmc.c | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/drivers/mmc/host/ricoh_mmc.c b/drivers/mmc/host/ricoh_mmc.c new file mode 100644 index 000000000000..1e8704533bc5 --- /dev/null +++ b/drivers/mmc/host/ricoh_mmc.c @@ -0,0 +1,151 @@ +/* + * 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"); + |