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path: root/drivers/mmc/host/ricoh_mmc.c
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Diffstat (limited to 'drivers/mmc/host/ricoh_mmc.c')
-rw-r--r--drivers/mmc/host/ricoh_mmc.c17
1 files changed, 11 insertions, 6 deletions
diff --git a/drivers/mmc/host/ricoh_mmc.c b/drivers/mmc/host/ricoh_mmc.c
index a16d7609e4e..be9e7b32b34 100644
--- a/drivers/mmc/host/ricoh_mmc.c
+++ b/drivers/mmc/host/ricoh_mmc.c
@@ -11,9 +11,10 @@
/*
* 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
+ * the Ricoh multi-function chips (R5CXXX) work. These chips implement
+ * the four main memory card controllers (SD, MMC, MS, xD) and one or both
+ * of cardbus or firewire. It happens that they implement SD and MMC
+ * support as separate controllers (and PCI functions). 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.
@@ -21,8 +22,10 @@
* 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.
+ * It seems to be the case that the relevant PCI registers to deactivate the
+ * MMC controller live on PCI function 0, which might be the cardbus controller
+ * or the firewire controller, depending on the particular chip in question. As
+ * such, it makes what this driver has to do unavoidably ugly. Such is life.
*/
#include <linux/pci.h>
@@ -143,6 +146,7 @@ static int __devinit ricoh_mmc_probe(struct pci_dev *pdev,
pci_get_device(PCI_VENDOR_ID_RICOH,
PCI_DEVICE_ID_RICOH_RL5C476, fw_dev))) {
if (PCI_SLOT(pdev->devfn) == PCI_SLOT(fw_dev->devfn) &&
+ PCI_FUNC(fw_dev->devfn) == 0 &&
pdev->bus == fw_dev->bus) {
if (ricoh_mmc_disable(fw_dev) != 0)
return -ENODEV;
@@ -160,6 +164,7 @@ static int __devinit ricoh_mmc_probe(struct pci_dev *pdev,
(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) &&
+ PCI_FUNC(fw_dev->devfn) == 0 &&
pdev->bus == fw_dev->bus) {
if (ricoh_mmc_disable(fw_dev) != 0)
return -ENODEV;
@@ -172,7 +177,7 @@ static int __devinit ricoh_mmc_probe(struct pci_dev *pdev,
if (!ctrlfound) {
printk(KERN_WARNING DRIVER_NAME
- ": Main firewire function not found. Cannot disable controller.\n");
+ ": Main Ricoh function not found. Cannot disable controller.\n");
return -ENODEV;
}