ricoh_mmc: port from driver to pci quirk

This patch solves nasty problem original driver has.

Original goal of the ricoh_mmc was to disable this device because then,
mmc cards can be read using standard SDHCI controller, thus avoiding
writing of yet another driver.

However, the act of disablement, makes other pci functions that belong to
this controller (xD and memstick) shift up one level, thus pci core has
now wrong idea about these devices.

To fix this issue, this patch moves the driver into the pci quirk section,
thus it is executes before the pci is enumerated, and therefore solving
that issue, also same sequence of commands is performed on resume for same
reasons.

Also regardless of the above, this way is cleaner.  You still need to set
CONFIG_MMC_RICOH_MMC to enable this quirk

Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
Acked-by: Philip Langdale <philipl@overt.org>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 85 insertions, 0 deletions

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 039e87b..81d19d5 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -2533,6 +2533,91 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x1518, quirk_i82576_sriov);
 
 #endif	/* CONFIG_PCI_IOV */
 
+/*
+ * This is a quirk for the Ricoh MMC controller found as a part of
+ * some mulifunction chips.
+
+ * This is very similiar and based on the ricoh_mmc driver written by
+ * Philip Langdale. Thank you for these magic sequences.
+ *
+ * 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.
+ * At that point, the SDHCI controller will start seeing them
+ * 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
+ *
+ * This has to be done early, because as soon as we disable the MMC controller
+ * other pci functions shift up one level, e.g. function #2 becomes function
+ * #1, and this will confuse the pci core.
+ */
+
+#ifdef CONFIG_MMC_RICOH_MMC
+static void ricoh_mmc_fixup_rl5c476(struct pci_dev *dev)
+{
+	/* disable via cardbus interface */
+	u8 write_enable;
+	u8 write_target;
+	u8 disable;
+
+	/* disable must be done via function #0 */
+	if (PCI_FUNC(dev->devfn))
+		return;
+
+	pci_read_config_byte(dev, 0xB7, &disable);
+	if (disable & 0x02)
+		return;
+
+	pci_read_config_byte(dev, 0x8E, &write_enable);
+	pci_write_config_byte(dev, 0x8E, 0xAA);
+	pci_read_config_byte(dev, 0x8D, &write_target);
+	pci_write_config_byte(dev, 0x8D, 0xB7);
+	pci_write_config_byte(dev, 0xB7, disable | 0x02);
+	pci_write_config_byte(dev, 0x8E, write_enable);
+	pci_write_config_byte(dev, 0x8D, write_target);
+
+	dev_notice(&dev->dev, "proprietary Ricoh MMC controller disabled (via cardbus function)\n");
+	dev_notice(&dev->dev, "MMC cards are now supported by standard SDHCI controller\n");
+}
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_RICOH, PCI_DEVICE_ID_RICOH_RL5C476, ricoh_mmc_fixup_rl5c476);
+DECLARE_PCI_FIXUP_RESUME_EARLY(PCI_VENDOR_ID_RICOH, PCI_DEVICE_ID_RICOH_RL5C476, ricoh_mmc_fixup_rl5c476);
+
+static void ricoh_mmc_fixup_r5c832(struct pci_dev *dev)
+{
+	/* disable via firewire interface */
+	u8 write_enable;
+	u8 disable;
+
+	/* disable must be done via function #0 */
+	if (PCI_FUNC(dev->devfn))
+		return;
+
+	pci_read_config_byte(dev, 0xCB, &disable);
+
+	if (disable & 0x02)
+		return;
+
+	pci_read_config_byte(dev, 0xCA, &write_enable);
+	pci_write_config_byte(dev, 0xCA, 0x57);
+	pci_write_config_byte(dev, 0xCB, disable | 0x02);
+	pci_write_config_byte(dev, 0xCA, write_enable);
+
+	dev_notice(&dev->dev, "proprietary Ricoh MMC controller disabled (via firewire function)\n");
+	dev_notice(&dev->dev, "MMC cards are now supported by standard SDHCI controller\n");
+}
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_RICOH, PCI_DEVICE_ID_RICOH_R5C832, ricoh_mmc_fixup_r5c832);
+DECLARE_PCI_FIXUP_RESUME_EARLY(PCI_VENDOR_ID_RICOH, PCI_DEVICE_ID_RICOH_R5C832, ricoh_mmc_fixup_r5c832);
+#endif /*CONFIG_MMC_RICOH_MMC*/
+
+
 static void pci_do_fixups(struct pci_dev *dev, struct pci_fixup *f,
 			  struct pci_fixup *end)
 {