Re: [PATCH 14/15] ide: rework the code for selecting the best DMA transfer mode
From: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Date: 2007-02-02 23:53:28
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Hi, Sergei Shtylyov wrote:
Hello. Bartlomiej Zolnierkiewicz wrote:quoted
[PATCH] ide: rework the code for selecting the best DMA transfer modeHere's another portion of comments...quoted
Depends on the "ide: fix UDMA/MWDMA/SWDMA masks" patch.quoted
* add ide_hwif_t.filter_udma_mask hook for filtering UDMA maskErm, maybe a shorter method name like udma_filter would go with the others better. But well, that's my taste. :-)
done
quoted
(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()quoted
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)...
The mode-from-mask approach is indeed nicer. If you send me a patch to use the mode-from-mask evaluation I'll happily apply it. :) However the array/loop approach is also definitively an improvement over the current code.
quoted
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)[...]quoted
-EXPORT_SYMBOL(ide_dma_speed);Alas, my ide_dma_speed() fix is going to be oudated rather quickly... :-)
C'est la vie :)
quoted
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...
yes...
quoted
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...
This can safely vanish when core code gets fixed to correctly check device+host supported PIO/DMA modes before calling ->tuneproc/->speedproc for user space originated code change requests. As for now IMHO it is the best to just leave it alone...
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 :-).
Actually, I have an unfinished patch to fix it but it depends on many other unfinished patches... *sigh*...
quoted
+ 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...quoted
@@ -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...quoted
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...
...some time later. 8)
quoted
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...
I don't see a problem with doing it during initialization but simplifying this code wasn't the goal of this patch and can be done in the future.
quoted
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...
ditto patches welcomed (I added this to the IDE tree TODO)
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... :-)
Please do. Thanks, Bart