[PATCH] pata_rz1000: Force readahead off on resume

The RZ1000 is a generic device except that it has a readahead fifo flaw
that corrupts. We force this off at init time but we want to be paranoid
and force it off at resume as well. I don't know of any actual hardware
that supports both RZ1000 and suspend to RAM but given its a disk muncher
better safe than sorry.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 33 insertions, 15 deletions

diff --git a/drivers/ata/pata_rz1000.c b/drivers/ata/pata_rz1000.c
index e4e5ea423fef..21567aba82d2 100644
--- a/drivers/ata/pata_rz1000.c
+++ b/drivers/ata/pata_rz1000.c
@@ -21,7 +21,7 @@
 #include <linux/libata.h>
 
 #define DRV_NAME        "pata_rz1000"
-#define DRV_VERSION     "0.2.2"
+#define DRV_VERSION     "0.2.3"
 
 
 /**
@@ -92,6 +92,8 @@ static struct scsi_host_template rz1000_sht = {
         .slave_configure        = ata_scsi_slave_config,
         .slave_destroy          = ata_scsi_slave_destroy,
         .bios_param             = ata_std_bios_param,
+        .resume                 = ata_scsi_device_resume,
+        .suspend                = ata_scsi_device_suspend,
 };
 
 static struct ata_port_operations rz1000_port_ops = {
@@ -129,6 +131,19 @@ static struct ata_port_operations rz1000_port_ops = {
         .host_stop      = ata_host_stop
 };
 
+static int rz1000_fifo_disable(struct pci_dev *pdev)
+{
+        u16 reg;
+        /* Be exceptionally paranoid as we must be sure to apply the fix */
+        if (pci_read_config_word(pdev, 0x40, &reg) != 0)
+                return -1;
+        reg &= 0xDFFF;
+        if (pci_write_config_word(pdev, 0x40, reg) != 0)
+                return -1;
+        printk(KERN_INFO DRV_NAME ": disabled chipset readahead.\n");
+        return 0;
+}
+
 /**
  *      rz1000_init_one - Register RZ1000 ATA PCI device with kernel services
  *      @pdev: PCI device to register
@@ -143,7 +158,6 @@ static int rz1000_init_one (struct pci_dev *pdev, const struct pci_device_id *en
 {
         static int printed_version;
         struct ata_port_info *port_info[2];
-        u16 reg;
         static struct ata_port_info info = {
                 .sht = &rz1000_sht,
                 .flags = ATA_FLAG_SLAVE_POSS | ATA_FLAG_SRST,
@@ -154,23 +168,25 @@ static int rz1000_init_one (struct pci_dev *pdev, const struct pci_device_id *en
         if (!printed_version++)
                 printk(KERN_DEBUG DRV_NAME " version " DRV_VERSION "\n");
 
-        /* Be exceptionally paranoid as we must be sure to apply the fix */
-        if (pci_read_config_word(pdev, 0x40, &reg) != 0)
-                goto fail;
-        reg &= 0xDFFF;
-        if (pci_write_config_word(pdev, 0x40, reg) != 0)
-                goto fail;
-        printk(KERN_INFO DRV_NAME ": disabled chipset readahead.\n");
-
-        port_info[0] = &info;
-        port_info[1] = &info;
-        return ata_pci_init_one(pdev, port_info, 2);
-fail:
+        if (rz1000_fifo_disable(pdev) == 0) {
+                port_info[0] = &info;
+                port_info[1] = &info;
+                return ata_pci_init_one(pdev, port_info, 2);
+        }
         printk(KERN_ERR DRV_NAME ": failed to disable read-ahead on chipset..\n");
         /* Not safe to use so skip */
         return -ENODEV;
 }
 
+static int rz1000_reinit_one(struct pci_dev *pdev)
+{
+        /* If this fails on resume (which is a "cant happen" case), we
+           must stop as any progress risks data loss */
+        if (rz1000_fifo_disable(pdev))
+                panic("rz1000 fifo");
+        return ata_pci_device_resume(pdev);
+}
+
 static const struct pci_device_id pata_rz1000[] = {
         { PCI_VDEVICE(PCTECH, PCI_DEVICE_ID_PCTECH_RZ1000), },
         { PCI_VDEVICE(PCTECH, PCI_DEVICE_ID_PCTECH_RZ1001), },
@@ -182,7 +198,9 @@ static struct pci_driver rz1000_pci_driver = {
         .name           = DRV_NAME,
         .id_table       = pata_rz1000,
         .probe          = rz1000_init_one,
-        .remove         = ata_pci_remove_one
+        .remove         = ata_pci_remove_one,
+        .suspend        = ata_pci_device_suspend,
+        .resume         = rz1000_reinit_one,
 };
 
 static int __init rz1000_init(void)