mmc: add Toshiba PCI SD controller driver

This patch resurrects an old never-finished driver for Toshiba PCI SD controllers found in some older Toshiba laptops (such as Portege R100):

02:0d.0 System peripheral [0880]: Toshiba America Info Systems SD TypA Controller [1179:0805] (rev 05)

The hardware is slow (around 2 MB/s - same in Windows) because it does not support bus mastering (busmaster enable bit cannot be set in PCI control reg). Also the card clock is limited to 16MHz (33MHz PCI clock divided by 2).

SD, SDHC and also MMC cards work. (MMC cards don't work in Windows) SDIO is not supported (don't have any SDIO card).

---
 drivers/mmc/host/Kconfig  |    5
 drivers/mmc/host/Makefile |    1
 drivers/mmc/host/toshsd.c |  751 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 drivers/mmc/host/toshsd.h |  178 ++++++++++++++
 4 files changed, 935 insertions(+)

index 7fc5099..29dc4ef 100644
@@ -665,3 +665,8 @@ config MMC_REALTEK_PCI
 	help
 	  Say Y here to include driver code to support SD/MMC card interface
 	  of Realtek PCI-E card reader
+
+config MMC_TOSHIBA_PCI
+	tristate "Toshiba Type A SD/MMC Card Interface Driver"
+	depends on PCI
+	help

index c41d0c3..2dd1617 100644
@@ -51,6 +51,7 @@ obj-$(CONFIG_MMC_USHC)		+= ushc.o
 obj-$(CONFIG_MMC_WMT)		+= wmt-sdmmc.o
 
 obj-$(CONFIG_MMC_REALTEK_PCI)	+= rtsx_pci_sdmmc.o
+obj-$(CONFIG_MMC_TOSHIBA_PCI)	+= toshsd.o
 
 obj-$(CONFIG_MMC_SDHCI_PLTFM)		+= sdhci-pltfm.o
 obj-$(CONFIG_MMC_SDHCI_CNS3XXX)		+= sdhci-cns3xxx.o

Ondrej Zary