Resurrect IT8172 IDE controller driver

Support for the IT8172 IDE controller was removed from the kernel
sometime after 2.6.18.  Support for the only boards that used the IT8172
was removed from the kernel after 2.6.18, as they had never compiled
since 2.6.0.  However, there are a couple of platforms that use this
chip: the PMC-Sierra Xiao Hu thin-client computer, which is no longer
in production, and the Linksys NSS4000 Network Attached Storage box,
which is based on the Xiao Hu board.  I am attempting to add support
for the Xiao Hu to the kernel, and this IT8172 IDE controller is the
first bit of code in this effort.

This patch resurrects the IT8172 IDE controller code.  I began with
the 2.6.18 version of the it8172.c file, and have moved it forward so
that it works with the latest version of the kernel.  I have run this
driver on a PMC-Sierra Xiao Hu board with the 2.6.28 kernel, and
I have had no problems with it in my configuration.  The attached patch
applies cleanly against 2.6.28.

Signed-off-by: Shane McDonald <mcdonald.shane@gmail.com>
Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: alan@lxorguk.ukuu.org.uk
[bart: s/HWIF(drive)/drive->hwif/]
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

3 files changed, 174 insertions, 0 deletions

diff --git a/drivers/ide/Kconfig b/drivers/ide/Kconfig
index 4ee85fcf9aaf..3f9503867e6b 100644
--- a/drivers/ide/Kconfig
+++ b/drivers/ide/Kconfig
@@ -511,6 +511,13 @@ config BLK_DEV_PIIX
           This allows the kernel to change PIO, DMA and UDMA speeds and to
           configure the chip to optimum performance.
 
+config BLK_DEV_IT8172
+        tristate "IT8172 IDE support"
+        select BLK_DEV_IDEDMA_PCI
+        help
+          This driver adds support for the IDE controller on the
+          IT8172 System Controller.
+
 config BLK_DEV_IT8213
         tristate "IT8213 IDE support"
         select BLK_DEV_IDEDMA_PCI
diff --git a/drivers/ide/Makefile b/drivers/ide/Makefile
index 410728992e6a..c2b9c93f0095 100644
--- a/drivers/ide/Makefile
+++ b/drivers/ide/Makefile
@@ -47,6 +47,7 @@ obj-$(CONFIG_BLK_DEV_SC1200)		+= sc1200.o
 obj-$(CONFIG_BLK_DEV_CY82C693)          += cy82c693.o
 obj-$(CONFIG_BLK_DEV_DELKIN)            += delkin_cb.o
 obj-$(CONFIG_BLK_DEV_HPT366)            += hpt366.o
+obj-$(CONFIG_BLK_DEV_IT8172)            += it8172.o
 obj-$(CONFIG_BLK_DEV_IT8213)            += it8213.o
 obj-$(CONFIG_BLK_DEV_IT821X)            += it821x.o
 obj-$(CONFIG_BLK_DEV_JMICRON)           += jmicron.o
diff --git a/drivers/ide/it8172.c b/drivers/ide/it8172.c
new file mode 100644
index 000000000000..e021078cd06b
--- /dev/null
+++ b/drivers/ide/it8172.c
@@ -0,0 +1,166 @@
+/*
+ *
+ * BRIEF MODULE DESCRIPTION
+ *      IT8172 IDE controller support
+ *
+ * Copyright (C) 2000 MontaVista Software Inc.
+ * Copyright (C) 2008 Shane McDonald
+ *
+ *  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  SOFTWARE  IS PROVIDED   ``AS  IS'' AND   ANY  EXPRESS OR IMPLIED
+ *  WARRANTIES,   INCLUDING, BUT NOT  LIMITED  TO, THE IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
+ *  NO  EVENT  SHALL   THE AUTHOR  BE    LIABLE FOR ANY   DIRECT, INDIRECT,
+ *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ *  NOT LIMITED   TO, PROCUREMENT OF  SUBSTITUTE GOODS  OR SERVICES; LOSS OF
+ *  USE, DATA,  OR PROFITS; OR  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ *  ANY THEORY OF LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT
+ *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ *  You should have received a copy of the  GNU General Public License along
+ *  with this program; if not, write  to the Free Software Foundation, Inc.,
+ *  675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/ioport.h>
+#include <linux/pci.h>
+#include <linux/ide.h>
+#include <linux/init.h>
+
+#define DRV_NAME "IT8172"
+
+static void it8172_set_pio_mode(ide_drive_t *drive, const u8 pio)
+{
+        ide_hwif_t *hwif        = drive->hwif;
+        struct pci_dev *dev     = to_pci_dev(hwif->dev);
+        u16 drive_enables;
+        u32 drive_timing;
+
+        /*
+         * The highest value of DIOR/DIOW pulse width and recovery time
+         * that can be set in the IT8172 is 8 PCI clock cycles.  As a result,
+         * it cannot be configured for PIO mode 0.  This table sets these
+         * parameters to the maximum supported by the IT8172.
+         */
+        static const u8 timings[] = { 0x3f, 0x3c, 0x1b, 0x12, 0x0a };
+
+        pci_read_config_word(dev, 0x40, &drive_enables);
+        pci_read_config_dword(dev, 0x44, &drive_timing);
+
+        /*
+         * Enable port 0x44. The IT8172 spec is confused; it calls
+         * this register the "Slave IDE Timing Register", but in fact,
+         * it controls timing for both master and slave drives.
+         */
+        drive_enables |= 0x4000;
+
+        drive_enables &= drive->dn ? 0xc006 : 0xc060;
+        if (drive->media == ide_disk)
+                /* enable prefetch */
+                drive_enables |= 0x0004 << (drive->dn * 4);
+        if (ata_id_has_iordy(drive->id))
+                /* enable IORDY sample-point */
+                drive_enables |= 0x0002 << (drive->dn * 4);
+
+        drive_timing &= drive->dn ? 0x00003f00 : 0x000fc000;
+        drive_timing |= timings[pio] << (drive->dn * 6 + 8);
+
+        pci_write_config_word(dev, 0x40, drive_enables);
+        pci_write_config_dword(dev, 0x44, drive_timing);
+}
+
+static void it8172_set_dma_mode(ide_drive_t *drive, const u8 speed)
+{
+        ide_hwif_t *hwif        = drive->hwif;
+        struct pci_dev *dev     = to_pci_dev(hwif->dev);
+        int a_speed             = 3 << (drive->dn * 4);
+        int u_flag              = 1 << drive->dn;
+        int u_speed             = 0;
+        u8 reg48, reg4a;
+
+        pci_read_config_byte(dev, 0x48, &reg48);
+        pci_read_config_byte(dev, 0x4a, &reg4a);
+
+        if (speed >= XFER_UDMA_0) {
+                u8 udma = speed - XFER_UDMA_0;
+                u_speed = udma << (drive->dn * 4);
+
+                pci_write_config_byte(dev, 0x48, reg48 | u_flag);
+                reg4a &= ~a_speed;
+                pci_write_config_byte(dev, 0x4a, reg4a | u_speed);
+        } else {
+                const u8 mwdma_to_pio[] = { 0, 3, 4 };
+                u8 pio;
+
+                pci_write_config_byte(dev, 0x48, reg48 & ~u_flag);
+                pci_write_config_byte(dev, 0x4a, reg4a & ~a_speed);
+
+                pio = mwdma_to_pio[speed - XFER_MW_DMA_0];
+
+                it8172_set_pio_mode(drive, pio);
+        }
+}
+
+
+static const struct ide_port_ops it8172_port_ops = {
+        .set_pio_mode   = it8172_set_pio_mode,
+        .set_dma_mode   = it8172_set_dma_mode,
+};
+
+static const struct ide_port_info it8172_port_info __devinitdata = {
+        .name           = DRV_NAME,
+        .port_ops       = &it8172_port_ops,
+        .enablebits     = { {0x41, 0x80, 0x80}, {0x00, 0x00, 0x00} },
+        .host_flags     = IDE_HFLAG_SINGLE,
+        .pio_mask       = ATA_PIO4 & ~ATA_PIO0,
+        .mwdma_mask     = ATA_MWDMA2,
+        .udma_mask      = ATA_UDMA2,
+};
+
+static int __devinit it8172_init_one(struct pci_dev *dev,
+                                        const struct pci_device_id *id)
+{
+        if ((dev->class >> 8) != PCI_CLASS_STORAGE_IDE)
+                return -ENODEV; /* IT8172 is more than an IDE controller */
+        return ide_pci_init_one(dev, &it8172_port_info, NULL);
+}
+
+static struct pci_device_id it8172_pci_tbl[] = {
+        { PCI_VDEVICE(ITE, PCI_DEVICE_ID_ITE_8172), 0 },
+        { 0, },
+};
+MODULE_DEVICE_TABLE(pci, it8172_pci_tbl);
+
+static struct pci_driver it8172_pci_driver = {
+        .name           = "IT8172_IDE",
+        .id_table       = it8172_pci_tbl,
+        .probe          = it8172_init_one,
+        .remove         = ide_pci_remove,
+        .suspend        = ide_pci_suspend,
+        .resume         = ide_pci_resume,
+};
+
+static int __init it8172_ide_init(void)
+{
+        return ide_pci_register_driver(&it8172_pci_driver);
+}
+
+static void __exit it8172_ide_exit(void)
+{
+        pci_unregister_driver(&it8172_pci_driver);
+}
+
+module_init(it8172_ide_init);
+module_exit(it8172_ide_exit);
+
+MODULE_AUTHOR("Steve Longerbeam");
+MODULE_DESCRIPTION("PCI driver module for ITE 8172 IDE");
+MODULE_LICENSE("GPL");