Re: [PATCH 14/15] ide: rework the code for selecting the best DMAtransfer mode

From: Sergei Shtylyov
Date: Mon Jan 22 2007 - 14:48:56 EST

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In reply to: Bartlomiej Zolnierkiewicz: "[PATCH 14/15] ide: rework the code for selecting the best DMA transfer mode"
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Hello.

Bartlomiej Zolnierkiewicz wrote:

[PATCH] ide: rework the code for selecting the best DMA transfer mode

Here's another portion of comments...

Depends on the "ide: fix UDMA/MWDMA/SWDMA masks" patch.

* add ide_hwif_t.filter_udma_mask hook for filtering UDMA mask

Erm, maybe a shorter method name like udma_filter would go with the others better. But well, that's my taste. :-)

(use it in alim15x3, hpt366, siimage and serverworks drivers)
* add ide_max_dma_mode() for finding best DMA mode for the device
(loosely based on some older libata-core.c code)
* convert ide_dma_speed() users to use ide_max_dma_mode()
* make ide_rate_filter() take "ide_drive_t *drive" as an argument instead
of "u8 mode" and teach it to how to use UDMA mask to do filtering
* use ide_rate_filter() in hpt366 driver
* remove no longer needed ide_dma_speed() and *_ratemask()
* unexport eighty_ninty_three()

Index: b/drivers/ide/ide-dma.c
===================================================================
--- a/drivers/ide/ide-dma.c
+++ b/drivers/ide/ide-dma.c
@@ -705,6 +705,80 @@ int ide_use_dma(ide_drive_t *drive)
EXPORT_SYMBOL_GPL(ide_use_dma);
+static const u8 xfer_mode_bases[] = {
+ XFER_UDMA_0,
+ XFER_MW_DMA_0,
+ XFER_SW_DMA_0,
+};
+
+static unsigned int ide_get_mode_mask(ide_drive_t *drive, u8 base)
+{
+ struct hd_driveid *id = drive->id;
+ ide_hwif_t *hwif = drive->hwif;
+ unsigned int mask = 0;
+
+ switch(base) {
+ case XFER_UDMA_0:
+ if ((id->field_valid & 4) == 0)
+ break;
+
+ mask = id->dma_ultra & hwif->ultra_mask;
+
+ if (hwif->filter_udma_mask)
+ mask &= hwif->filter_udma_mask(drive);
+
+ if ((mask & 0x78) && (eighty_ninty_three(drive) == 0))
+ mask &= 0x07;
+ break;
+ case XFER_MW_DMA_0:
+ mask = id->dma_mword & hwif->mwdma_mask;
+ break;
+ case XFER_SW_DMA_0:
+ mask = id->dma_1word & hwif->swdma_mask;
+ break;
+ default:
+ BUG();
+ break;
+ }
+
+ return mask;
+}
+
+/**
+ * ide_max_dma_mode - compute DMA speed
+ * @drive: IDE device
+ *
+ * Checks the drive capabilities and returns the speed to use
+ * for the DMA transfer. Returns 0 if the drive is incapable
+ * of DMA transfers.
+ */
+
+u8 ide_max_dma_mode(ide_drive_t *drive)
+{
+ ide_hwif_t *hwif = drive->hwif;
+ unsigned int mask;
+ int x, i;
+ u8 mode = 0;
+
+ if (drive->media != ide_disk && hwif->atapi_dma == 0)
+ return 0;
+
+ for (i = 0; i < ARRAY_SIZE(xfer_mode_bases); i++) {
+ mask = ide_get_mode_mask(drive, xfer_mode_bases[i]);
+ x = fls(mask) - 1;
+ if (x >= 0) {
+ mode = xfer_mode_bases[i] + x;
+ break;
+ }
+ }
+
+ printk(KERN_DEBUG "%s: selected mode 0x%x\n", drive->name, mode);
+
+ return mode;
+}
+
+EXPORT_SYMBOL_GPL(ide_max_dma_mode);
+

I didn't quite like the array/loop approach but well, that's my taste (I'd
rather put the mode-from-mask evaluation to the function and call it thrice)...

Index: b/drivers/ide/ide-lib.c
===================================================================
--- a/drivers/ide/ide-lib.c
+++ b/drivers/ide/ide-lib.c
@@ -69,123 +69,34 @@ char *ide_xfer_verbose (u8 xfer_rate)
EXPORT_SYMBOL(ide_xfer_verbose);
/**
- * ide_dma_speed - compute DMA speed
- * @drive: drive
- * @mode: modes available
- *
- * Checks the drive capabilities and returns the speed to use
- * for the DMA transfer. Returns 0 if the drive is incapable
- * of DMA transfers.
- */
- -u8 ide_dma_speed(ide_drive_t *drive, u8 mode)

[...]

-EXPORT_SYMBOL(ide_dma_speed);

Alas, my ide_dma_speed() fix is going to be oudated rather quickly... :-)

Index: b/drivers/ide/pci/hpt366.c
===================================================================
--- a/drivers/ide/pci/hpt366.c
+++ b/drivers/ide/pci/hpt366.c
@@ -513,43 +513,31 @@ static int check_in_drive_list(ide_drive
return 0;
}
-static u8 hpt3xx_ratemask(ide_drive_t *drive)
-{
- struct hpt_info *info = pci_get_drvdata(HWIF(drive)->pci_dev);
- u8 mode = info->max_mode;
-
- if (!eighty_ninty_three(drive) && mode)
- mode = min(mode, (u8)1);
- return mode;
-}
-
/*
* Note for the future; the SATA hpt37x we must set
* either PIO or UDMA modes 0,4,5
*/
- -static u8 hpt3xx_ratefilter(ide_drive_t *drive, u8 speed)
+
+static u8 hpt3xx_filter_udma_mask(ide_drive_t *drive)
{
struct hpt_info *info = pci_get_drvdata(HWIF(drive)->pci_dev);
u8 chip_type = info->chip_type;
- u8 mode = hpt3xx_ratemask(drive);
-
- if (drive->media != ide_disk)
- return min(speed, (u8)XFER_PIO_4);
+ u8 mode = info->max_mode;
+ u8 mask;
switch (mode) {
case 0x04:
- speed = min_t(u8, speed, XFER_UDMA_6);
+ mask = 0x7f;
break;
case 0x03:
- speed = min_t(u8, speed, XFER_UDMA_5);
+ mask = 0x3f;
if (chip_type >= HPT374)
break;
if (!check_in_drive_list(drive, bad_ata100_5))
goto check_bad_ata33;
/* fall thru */
case 0x02:
- speed = min_t(u8, speed, XFER_UDMA_4);
+ mask = 0x1f;
/*
* CHECK ME, Does this need to be changed to HPT374 ??
@@ -560,13 +548,13 @@ static u8 hpt3xx_ratefilter(ide_drive_t !check_in_drive_list(drive, bad_ata66_4))
goto check_bad_ata33;
- speed = min_t(u8, speed, XFER_UDMA_3);
+ mask = 0x0f;
if (HPT366_ALLOW_ATA66_3 &&
!check_in_drive_list(drive, bad_ata66_3))
goto check_bad_ata33;
/* fall thru */
case 0x01:
- speed = min_t(u8, speed, XFER_UDMA_2);
+ mask = 0x07;
check_bad_ata33:
if (chip_type >= HPT370A)
@@ -576,10 +564,10 @@ static u8 hpt3xx_ratefilter(ide_drive_t /* fall thru */
case 0x00:
default:
- speed = min_t(u8, speed, XFER_MW_DMA_2);
+ mask = 0x00;
break;
}
- return speed;
+ return mask;
}

Erm, I see. This driver will need some redesign because 'struct hpt_info' was fitted for the old rate filtering model. Looks like the 'max_mode' field should be replaced by 'ultra_mask' there...

static u32 get_speed_setting(u8 speed, struct hpt_info *info)
@@ -607,12 +595,19 @@ static int hpt36x_tune_chipset(ide_drive
ide_hwif_t *hwif = HWIF(drive);
struct pci_dev *dev = hwif->pci_dev;
struct hpt_info *info = pci_get_drvdata(dev);
- u8 speed = hpt3xx_ratefilter(drive, xferspeed);
+ u8 speed = ide_rate_filter(drive, xferspeed);
u8 itr_addr = drive->dn ? 0x44 : 0x40;
- u32 itr_mask = speed < XFER_MW_DMA_0 ? 0x30070000 :
- (speed < XFER_UDMA_0 ? 0xc0070000 : 0xc03800ff);
- u32 new_itr = get_speed_setting(speed, info);
u32 old_itr = 0;
+ u32 itr_mask, new_itr;
+
+ /* TODO: move this to ide_rate_filter() [ check ->atapi_dma ] */
+ if (drive->media != ide_disk)
+ speed = min_t(u8, speed, XFER_PIO_4);
+

When I think about it, it seems quite stupid to set a PIO mode instead of a requested DMA one. So, this is actually a questionable piece of code in this driver...

Well, I must note the sorrow fact that both the IDE susbsytem as a whole doesn't keep track of PIO/DMA modes separately (having only current_mode) and the many drivers also fail to handle the timing registers shared by PIO/DMA modes correctly (well, it's actually also a hardware design issue :-).

+ itr_mask = speed < XFER_MW_DMA_0 ? 0x30070000 :
+ (speed < XFER_UDMA_0 ? 0xc0070000 : 0xc03800ff);
+
+ new_itr = get_speed_setting(speed, info);

Well, I liked this code where it was. But anyway, it's going to be replaced RSN...

@@ -632,12 +627,19 @@ static int hpt37x_tune_chipset(ide_drive
ide_hwif_t *hwif = HWIF(drive);
struct pci_dev *dev = hwif->pci_dev;
struct hpt_info *info = pci_get_drvdata(dev);
- u8 speed = hpt3xx_ratefilter(drive, xferspeed);
+ u8 speed = ide_rate_filter(drive, xferspeed);
u8 itr_addr = 0x40 + (drive->dn * 4);
- u32 itr_mask = speed < XFER_MW_DMA_0 ? 0x303c0000 :
- (speed < XFER_UDMA_0 ? 0xc03c0000 : 0xc1c001ff);
- u32 new_itr = get_speed_setting(speed, info);
u32 old_itr = 0;
+ u32 itr_mask, new_itr;
+
+ /* TODO: move this to ide_rate_filter() [ check ->atapi_dma ] */
+ if (drive->media != ide_disk)
+ speed = min_t(u8, speed, XFER_PIO_4);
+
+ itr_mask = speed < XFER_MW_DMA_0 ? 0x303c0000 :
+ (speed < XFER_UDMA_0 ? 0xc03c0000 : 0xc1c001ff);
+
+ new_itr = get_speed_setting(speed, info);

Same comments here...

Index: b/drivers/ide/pci/serverworks.c
===================================================================
--- a/drivers/ide/pci/serverworks.c
+++ b/drivers/ide/pci/serverworks.c
@@ -65,16 +65,16 @@ static int check_in_drive_lists (ide_dri
return 0;
}
-static u8 svwks_ratemask (ide_drive_t *drive)
+static u8 svwks_filter_udma_mask(ide_drive_t *drive)
{
struct pci_dev *dev = HWIF(drive)->pci_dev;
- u8 mode = 0;
+ u8 mask = 0;

Hm, this looks like it needs rework...

if (!svwks_revision)
pci_read_config_byte(dev, PCI_REVISION_ID, &svwks_revision);
if (dev->device == PCI_DEVICE_ID_SERVERWORKS_HT1000IDE)
- return 2;
+ return 0x1f;
if (dev->device == PCI_DEVICE_ID_SERVERWORKS_OSB4IDE) {
u32 reg = 0;
if (isa_dev)
@@ -86,25 +86,31 @@ static u8 svwks_ratemask (ide_drive_t *d
if(drive->media == ide_disk)
return 0;
/* Check the OSB4 DMA33 enable bit */
- return ((reg & 0x00004000) == 0x00004000) ? 1 : 0;
+ return ((reg & 0x00004000) == 0x00004000) ? 0x07 : 0;
} else if (svwks_revision < SVWKS_CSB5_REVISION_NEW) {
- return 1;
+ return 0x07;
} else if (svwks_revision >= SVWKS_CSB5_REVISION_NEW) {
- u8 btr = 0;
+ u8 btr = 0, mode;
pci_read_config_byte(dev, 0x5A, &btr);
mode = btr & 0x3;
- if (!eighty_ninty_three(drive))
- mode = min(mode, (u8)1);
+
/* If someone decides to do UDMA133 on CSB5 the same
issue will bite so be inclusive */
if (mode > 2 && check_in_drive_lists(drive, svwks_bad_ata100))
mode = 2;
+
+ switch(mode) {
+ case 2: mask = 0x1f; break;
+ case 1: mask = 0x07; break;
+ default: mask = 0x00; break;
+ }
}
if (((dev->device == PCI_DEVICE_ID_SERVERWORKS_CSB6IDE) ||
(dev->device == PCI_DEVICE_ID_SERVERWORKS_CSB6IDE2)) &&
(!(PCI_FUNC(dev->devfn) & 1)))
- mode = 2;
- return mode;
+ mask = 0x1f;
+
+ return mask;
}

Hm, what was the problem with setting the proper masks based on PCI device ID in the init. code?
That'd have greatly simplified the filter...

Index: b/drivers/ide/pci/siimage.c
===================================================================
--- a/drivers/ide/pci/siimage.c
+++ b/drivers/ide/pci/siimage.c
@@ -116,45 +116,41 @@ static inline unsigned long siimage_seld
}
/**
- * siimage_ratemask - Compute available modes
- * @drive: IDE drive
+ * sil_filter_udma_mask - compute UDMA mask
+ * @drive: IDE device
+ *
+ * Compute the available UDMA speeds for the device on the interface.
*
- * Compute the available speeds for the devices on the interface.
* For the CMD680 this depends on the clocking mode (scsc), for the
- * SI3312 SATA controller life is a bit simpler. Enforce UDMA33
- * as a limit if there is no 80pin cable present.
+ * SI3112 SATA controller life is a bit simpler.
*/
- -static byte siimage_ratemask (ide_drive_t *drive)
+
+static u8 sil_filter_udma_mask(ide_drive_t *drive)
{
- ide_hwif_t *hwif = HWIF(drive);
- u8 mode = 0, scsc = 0;
+ ide_hwif_t *hwif = drive->hwif;
unsigned long base = (unsigned long) hwif->hwif_data;
+ u8 mask = 0, scsc = 0;
if (hwif->mmio)
scsc = hwif->INB(base + 0x4A);
else
pci_read_config_byte(hwif->pci_dev, 0x8A, &scsc);
- if(is_sata(hwif))
- {
- if(strstr(drive->id->model, "Maxtor"))
- return 3;
- return 4;
+ if (is_sata(hwif)) {
+ mask = strstr(drive->id->model, "Maxtor") ? 0x3f : 0x7f;
+ goto out;
}
-
+
if ((scsc & 0x30) == 0x10) /* 133 */
- mode = 4;
+ mask = 0x7f;
else if ((scsc & 0x30) == 0x20) /* 2xPCI */
- mode = 4;
+ mask = 0x7f;
else if ((scsc & 0x30) == 0x00) /* 100 */
- mode = 3;
+ mask = 0x3f;
else /* Disabled ? */
BUG();

Most probably this is doable at init. time also...

MBR, Sergei

PS: I understand that the intent wasn not to make this rewrite optimal but
do it quick and with least affect. And I certainly may handle hpt366.c redesign... :-)

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Next message: John Stoffel: "ATA - pata_mpiix.c support for 82371AB chipsets?"
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In reply to: Bartlomiej Zolnierkiewicz: "[PATCH 14/15] ide: rework the code for selecting the best DMA transfer mode"
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