ide: filter out "default" transfer mode values in set_xfer_rate()

* Filter out "default" transfer mode values (0x00 - default PIO mode,
  0x01 - default PIO mode w/ IORDY disabled) in write handler for obsoleted
  /proc/ide/hd?/settings:current_speed setting.

  Allowing "default" transfer mode values is a dangerous thing to do as
  we don't support programming controller to the "default" transfer mode
  and devices often use different values for the default and maximum PIO
  mode (i.e. PIO2 default and PIO4 maximum) so the controller will stay
  programmed for higher PIO mode while device will use the lower PIO mode.

  There is no functionality loss as by using special IOCTLs device can
  still be programmed to "default" transfer modes (it is only useful for
  debugging/testing purposes anyway).

* Remove no longer needed IDE_HFLAG_ABUSE_SET_DMA_MODE host flag, it was
  previously used by few host drivers to program the controller to PIO0
  timings for "default" transfer mode == 0x01 (although some host drivers
  would program invalid PIO timings instead).

* Cleanup ide_set_xfer_rate() and add BUG_ON().

Suggested-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

10 files changed, 4 insertions, 19 deletions

diff --git a/drivers/ide/pci/aec62xx.c b/drivers/ide/pci/aec62xx.c
index ae7a4329a58..fbc43e121e6 100644
--- a/drivers/ide/pci/aec62xx.c
+++ b/drivers/ide/pci/aec62xx.c
@@ -195,7 +195,6 @@ static const struct ide_port_info aec62xx_chipsets[] __devinitdata = {
 		.host_flags	= IDE_HFLAG_SERIALIZE |
 				  IDE_HFLAG_NO_ATAPI_DMA |
 				  IDE_HFLAG_NO_DSC |
-				  IDE_HFLAG_ABUSE_SET_DMA_MODE |
 				  IDE_HFLAG_OFF_BOARD,
 		.pio_mask	= ATA_PIO4,
 		.mwdma_mask	= ATA_MWDMA2,
@@ -205,7 +204,6 @@ static const struct ide_port_info aec62xx_chipsets[] __devinitdata = {
 		.init_chipset	= init_chipset_aec62xx,
 		.port_ops	= &atp86x_port_ops,
 		.host_flags	= IDE_HFLAG_NO_ATAPI_DMA | IDE_HFLAG_NO_AUTODMA |
-				  IDE_HFLAG_ABUSE_SET_DMA_MODE |
 				  IDE_HFLAG_OFF_BOARD,
 		.pio_mask	= ATA_PIO4,
 		.mwdma_mask	= ATA_MWDMA2,
@@ -216,7 +214,6 @@ static const struct ide_port_info aec62xx_chipsets[] __devinitdata = {
 		.enablebits	= {{0x4a,0x02,0x02}, {0x4a,0x04,0x04}},
 		.port_ops	= &atp86x_port_ops,
 		.host_flags	= IDE_HFLAG_NO_ATAPI_DMA |
-				  IDE_HFLAG_ABUSE_SET_DMA_MODE |
 				  IDE_HFLAG_NON_BOOTABLE,
 		.pio_mask	= ATA_PIO4,
 		.mwdma_mask	= ATA_MWDMA2,
@@ -226,7 +223,6 @@ static const struct ide_port_info aec62xx_chipsets[] __devinitdata = {
 		.init_chipset	= init_chipset_aec62xx,
 		.port_ops	= &atp86x_port_ops,
 		.host_flags	= IDE_HFLAG_NO_ATAPI_DMA |
-				  IDE_HFLAG_ABUSE_SET_DMA_MODE |
 				  IDE_HFLAG_OFF_BOARD,
 		.pio_mask	= ATA_PIO4,
 		.mwdma_mask	= ATA_MWDMA2,
@@ -237,7 +233,6 @@ static const struct ide_port_info aec62xx_chipsets[] __devinitdata = {
 		.enablebits	= {{0x4a,0x02,0x02}, {0x4a,0x04,0x04}},
 		.port_ops	= &atp86x_port_ops,
 		.host_flags	= IDE_HFLAG_NO_ATAPI_DMA |
-				  IDE_HFLAG_ABUSE_SET_DMA_MODE |
 				  IDE_HFLAG_OFF_BOARD,
 		.pio_mask	= ATA_PIO4,
 		.mwdma_mask	= ATA_MWDMA2,
diff --git a/drivers/ide/pci/amd74xx.c b/drivers/ide/pci/amd74xx.c
index 0bfcdd0e77b..ef7d971031e 100644
--- a/drivers/ide/pci/amd74xx.c
+++ b/drivers/ide/pci/amd74xx.c
@@ -218,7 +218,6 @@ static const struct ide_port_ops amd_port_ops = {
 
 #define IDE_HFLAGS_AMD \
 	(IDE_HFLAG_PIO_NO_BLACKLIST | \
-	 IDE_HFLAG_ABUSE_SET_DMA_MODE | \
 	 IDE_HFLAG_POST_SET_MODE | \
 	 IDE_HFLAG_IO_32BIT | \
 	 IDE_HFLAG_UNMASK_IRQS)
diff --git a/drivers/ide/pci/cs5520.c b/drivers/ide/pci/cs5520.c
index d30cb4d99c4..e8e7df1915b 100644
--- a/drivers/ide/pci/cs5520.c
+++ b/drivers/ide/pci/cs5520.c
@@ -97,8 +97,7 @@ static const struct ide_port_ops cs5520_port_ops = {
 		.name		= name_str,			\
 		.port_ops	= &cs5520_port_ops,		\
 		.host_flags	= IDE_HFLAG_ISA_PORTS |		\
-				  IDE_HFLAG_CS5520 |		\
-				  IDE_HFLAG_ABUSE_SET_DMA_MODE, \
+				  IDE_HFLAG_CS5520,		\
 		.pio_mask	= ATA_PIO4,			\
 	}
 
diff --git a/drivers/ide/pci/cs5535.c b/drivers/ide/pci/cs5535.c
index dc97c48623f..5404fe4f701 100644
--- a/drivers/ide/pci/cs5535.c
+++ b/drivers/ide/pci/cs5535.c
@@ -171,8 +171,7 @@ static const struct ide_port_ops cs5535_port_ops = {
 static const struct ide_port_info cs5535_chipset __devinitdata = {
 	.name		= "CS5535",
 	.port_ops	= &cs5535_port_ops,
-	.host_flags	= IDE_HFLAG_SINGLE | IDE_HFLAG_POST_SET_MODE |
-			  IDE_HFLAG_ABUSE_SET_DMA_MODE,
+	.host_flags	= IDE_HFLAG_SINGLE | IDE_HFLAG_POST_SET_MODE,
 	.pio_mask	= ATA_PIO4,
 	.mwdma_mask	= ATA_MWDMA2,
 	.udma_mask	= ATA_UDMA4,
diff --git a/drivers/ide/pci/hpt34x.c b/drivers/ide/pci/hpt34x.c
index 84c36c11719..9e1d1c4741d 100644
--- a/drivers/ide/pci/hpt34x.c
+++ b/drivers/ide/pci/hpt34x.c
@@ -123,7 +123,6 @@ static const struct ide_port_ops hpt34x_port_ops = {
 #define IDE_HFLAGS_HPT34X \
 	(IDE_HFLAG_NO_ATAPI_DMA | \
 	 IDE_HFLAG_NO_DSC | \
-	 IDE_HFLAG_ABUSE_SET_DMA_MODE | \
 	 IDE_HFLAG_NO_AUTODMA)
 
 static const struct ide_port_info hpt34x_chipsets[] __devinitdata = {
diff --git a/drivers/ide/pci/hpt366.c b/drivers/ide/pci/hpt366.c
index e5651cefa39..1f1135ce7cd 100644
--- a/drivers/ide/pci/hpt366.c
+++ b/drivers/ide/pci/hpt366.c
@@ -1409,7 +1409,6 @@ static int __devinit hpt36x_init(struct pci_dev *dev, struct pci_dev *dev2)
 
 #define IDE_HFLAGS_HPT3XX \
 	(IDE_HFLAG_NO_ATAPI_DMA | \
-	 IDE_HFLAG_ABUSE_SET_DMA_MODE | \
 	 IDE_HFLAG_OFF_BOARD)
 
 static const struct ide_port_ops hpt3xx_port_ops = {
diff --git a/drivers/ide/pci/pdc202xx_old.c b/drivers/ide/pci/pdc202xx_old.c
index 1c2f9df3112..e54dc653b8c 100644
--- a/drivers/ide/pci/pdc202xx_old.c
+++ b/drivers/ide/pci/pdc202xx_old.c
@@ -312,7 +312,6 @@ static void __devinit pdc202ata4_fixup_irq(struct pci_dev *dev,
 
 #define IDE_HFLAGS_PDC202XX \
 	(IDE_HFLAG_ERROR_STOPS_FIFO | \
-	 IDE_HFLAG_ABUSE_SET_DMA_MODE | \
 	 IDE_HFLAG_OFF_BOARD)
 
 static const struct ide_port_ops pdc20246_port_ops = {
diff --git a/drivers/ide/pci/serverworks.c b/drivers/ide/pci/serverworks.c
index a1fb20826a5..127ccb45e26 100644
--- a/drivers/ide/pci/serverworks.c
+++ b/drivers/ide/pci/serverworks.c
@@ -349,9 +349,7 @@ static const struct ide_port_ops svwks_port_ops = {
 	.cable_detect		= svwks_cable_detect,
 };
 
-#define IDE_HFLAGS_SVWKS \
-	(IDE_HFLAG_LEGACY_IRQS | \
-	 IDE_HFLAG_ABUSE_SET_DMA_MODE)
+#define IDE_HFLAGS_SVWKS IDE_HFLAG_LEGACY_IRQS
 
 static const struct ide_port_info serverworks_chipsets[] __devinitdata = {
 	{	/* 0 */
diff --git a/drivers/ide/pci/tc86c001.c b/drivers/ide/pci/tc86c001.c
index a81d47c55ce..477e1979010 100644
--- a/drivers/ide/pci/tc86c001.c
+++ b/drivers/ide/pci/tc86c001.c
@@ -206,8 +206,7 @@ static const struct ide_port_info tc86c001_chipset __devinitdata = {
 	.init_hwif	= init_hwif_tc86c001,
 	.port_ops	= &tc86c001_port_ops,
 	.dma_ops	= &tc86c001_dma_ops,
-	.host_flags	= IDE_HFLAG_SINGLE | IDE_HFLAG_OFF_BOARD |
-			  IDE_HFLAG_ABUSE_SET_DMA_MODE,
+	.host_flags	= IDE_HFLAG_SINGLE | IDE_HFLAG_OFF_BOARD,
 	.pio_mask	= ATA_PIO4,
 	.mwdma_mask	= ATA_MWDMA2,
 	.udma_mask	= ATA_UDMA4,
diff --git a/drivers/ide/pci/via82cxxx.c b/drivers/ide/pci/via82cxxx.c
index e47384c70c4..09dc4803ef9 100644
--- a/drivers/ide/pci/via82cxxx.c
+++ b/drivers/ide/pci/via82cxxx.c
@@ -425,7 +425,6 @@ static const struct ide_port_info via82cxxx_chipset __devinitdata = {
 	.enablebits	= { { 0x40, 0x02, 0x02 }, { 0x40, 0x01, 0x01 } },
 	.port_ops	= &via_port_ops,
 	.host_flags	= IDE_HFLAG_PIO_NO_BLACKLIST |
-			  IDE_HFLAG_ABUSE_SET_DMA_MODE |
 			  IDE_HFLAG_POST_SET_MODE |
 			  IDE_HFLAG_IO_32BIT,
 	.pio_mask	= ATA_PIO5,