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