Regards,
Onkar
On Fri, Apr 9, 2010 at 9:41 AM, Peter Teoh <htmldeveloper@xxxxxxxxx> wrote:
On Fri, Apr 9, 2010 at 11:54 AM, Onkar Mahajan <kern.devel@xxxxxxxxx> wrote:I found one link for WD:
> Thank you very much sir. That was a good advise.
> I will try to do that. But , If I face difficulties is there
> any mailing list wherein I can post SATA related questions.
http://ssdportal.wdc.com/documents/datasheets/5000FS.pdf
somewhere in page 17 are the ATA commands for examples....
SATA mailing list may be your alternatives? (search for "linux-ide"
at http://vger.kernel.org/vger-lists.html, or perhaps many others?)
--
>
> Thanks & regards,
> Onkar
>
> On Fri, Apr 9, 2010 at 8:59 AM, Peter Teoh <htmldeveloper@xxxxxxxxx> wrote:
>>
>> On Wed, Apr 7, 2010 at 1:49 PM, Onkar Mahajan <kern.devel@xxxxxxxxx>
>> wrote:
>> > Greg,
>> > My intention is to learn to write a SATA driver with the hardware
>> > that I have. I have a SATA hard drive from Western Digital (MDL :
>> > WD800JD-75MSAS)
>> > and SATA controller (Intel 82801 GB/GR/GH ( ICH7 family ) for which the
>> > drivers are already
>> > present. I want to unload the drivers and reverse engineer them and make
>> > them working.
>> > Is it a good way to learn SATA/SCSI drivers ?? Please guide me with your
>> > invaluable experience.
>> >
>>
>> Not sure if it is useful to you or not, but the following are
>> extracted from my emails to my students working on the SATA drivers
>> right now :-) (sorry I did not have time to edit it...but if u
>> learning....just absorbed everything :-), and if u have time, find the
>> differences between the current drivers and those of the datasheet, so
>> as to add in new functionalities to the drivers.
>> but....but...but.....this is easier said than done....even for
>> me!!!!).
>>
>> Looking up the datasheet (WD u must find for yourself):
>>
>> http://www.seagate.com/support/disc/manuals/sata/100402371a.pdf
>>
>> Looking further into page 47:
>>
>> Supported ATA commands
>>
>> The following table lists Serial ATA standard commands that the drive
>> supports. For a detailed description of the ATA commands, refer to the
>> Serial ATA: High Speed Serialized AT Attachment specification. See
>> “S.M.A.R.T. commands” on page 44.for details and subcommands used in
>> the S.M.A.R.T. implementation.
>>
>> A list of all the command supported is listed:
>>
>> Identify Device
>> ECH
>> Idle
>> 97H or E3H
>>
>> which is inside drivers/ata/libata-eh.c:
>>
>> 2135 const char *ata_get_cmd_descript(u8 command)
>> 2136 {
>> 2137 #ifdef CONFIG_ATA_VERBOSE_ERROR
>> 2138 static const struct
>> 2139 {
>> 2140 u8 command;
>> 2141 const char *text;
>> 2142 } cmd_descr[] = {
>> 2143 { ATA_CMD_DEV_RESET, "DEVICE RESET" },
>> 2144 { ATA_CMD_CHK_POWER, "CHECK POWER MODE" },
>> 2145 { ATA_CMD_STANDBY, "STANDBY" },
>> 2146 { ATA_CMD_IDLE, "IDLE" },
>> 2147 { ATA_CMD_EDD, "EXECUTE DEVICE
>> DIAGNOSTIC" },
>> 2148 { ATA_CMD_DOWNLOAD_MICRO, "DOWNLOAD MICROCODE"
>> },
>> 2149 { ATA_CMD_NOP, "NOP" },
>> 2150 { ATA_CMD_FLUSH, "FLUSH CACHE" },
>> 2151 { ATA_CMD_FLUSH_EXT, "FLUSH CACHE EXT" },
>> 2152 { ATA_CMD_ID_ATA, "IDENTIFY DEVICE"
>> },========================>
>> 2153 { ATA_CMD_ID_ATAPI, "IDENTIFY PACKET
>> DEVICE" },
>>
>> and this is called inside libata-acpi.c:
>>
>> 663 /**
>> 664 * ata_acpi_run_tf - send taskfile registers to host controller
>> 665 * @dev: target ATA device
>> 666 * @gtf: raw ATA taskfile register set (0x1f1 - 0x1f7)
>> 667 *
>> 668 * Outputs ATA taskfile to standard ATA host controller using MMIO
>> 669 * or PIO as indicated by the ATA_FLAG_MMIO flag.
>> 670 * Writes the control, feature, nsect, lbal, lbam, and lbah
>> registers.
>> 671 * Optionally (ATA_TFLAG_LBA48) writes hob_feature, hob_nsect,
>> 672 * hob_lbal, hob_lbam, and hob_lbah.
>> 673 *
>> 674 * This function waits for idle (!BUSY and !DRQ) after writing
>> 675 * registers. If the control register has a new value, this
>> 676 * function also waits for idle after writing control and before
>> 677 * writing the remaining registers.
>> 678 *
>> 679 * LOCKING:
>> 680 * EH context.
>> 681 *
>> 682 * RETURNS:
>> 683 * 1 if command is executed successfully. 0 if ignored, rejected or
>> 684 * filtered out, -errno on other errors.
>> 685 */
>> 686 static int ata_acpi_run_tf(struct ata_device *dev,
>> 687 const struct ata_acpi_gtf *gtf,
>> 688 const struct ata_acpi_gtf *prev_gtf)
>> 689 {
>> 690 struct ata_taskfile *pptf = NULL;
>> 691 struct ata_taskfile tf, ptf, rtf;
>> 692 unsigned int err_mask;
>> 693 const char *level;
>> 694 const char *descr;
>> 695 char msg[60];
>> 696 int rc;
>> 697
>> 698 if ((gtf->tf[0] == 0) && (gtf->tf[1] == 0) && (gtf->tf[2] ==
>> 0)
>> 699 && (gtf->tf[3] == 0) && (gtf->tf[4] == 0) && (gtf->tf[5]
>> == 0)
>> 700 && (gtf->tf[6] == 0))
>> 701 return 0;
>> 702
>> 703 ata_acpi_gtf_to_tf(dev, gtf, &tf);
>> 704 if (prev_gtf) {
>> 705 ata_acpi_gtf_to_tf(dev, prev_gtf, &ptf);
>> 706 pptf = &ptf;
>> 707 }
>> 708
>> 709 if (!ata_acpi_filter_tf(dev, &tf, pptf)) {
>> 710 rtf = tf;
>> 711 err_mask = ata_exec_internal(dev, &rtf, NULL,
>> 712 DMA_NONE, NULL, 0, 0);
>> 713
>> 714 switch (err_mask) {
>> 715 case 0:
>> 716 level = KERN_DEBUG;
>> 717 snprintf(msg, sizeof(msg), "succeeded");
>> 718 rc = 1;
>> 719 break;
>> 720
>> 721 case AC_ERR_DEV:
>> 722 level = KERN_INFO;
>> 723 snprintf(msg, sizeof(msg),
>> 724 "rejected by device (Stat=0x%02x
>> Err=0x%02x)",
>> 725 rtf.command, rtf.feature);
>> 726 rc = 0;
>> 727 break;
>> 728
>> 729 default:
>> 730 level = KERN_ERR;
>> 731 snprintf(msg, sizeof(msg),
>> 732 "failed (Emask=0x%x Stat=0x%02x
>> Err=0x%02x)",
>> 733 err_mask, rtf.command, rtf.feature);
>> 734 rc = -EIO;
>> 735 break;
>> 736 }
>> 737 } else {
>> 738 level = KERN_INFO;
>> 739 snprintf(msg, sizeof(msg), "filtered out");
>> 740 rc = 0;
>> 741 }
>> 742 descr = ata_get_cmd_descript(tf.command);
>> 743
>>
>>
>> And the systemtap tracing:
>>
>> ata_scsi_queuecmd
>> 0xffffffff8162c26d : ata_scsi_queuecmd+0x0/0x98 [kernel]
>> 0xffffffff81515625 : scsi_dispatch_cmd+0x1e1/0x25f [kernel]
>> 0xffffffff8151b43b : scsi_request_fn+0x3f2/0x53b [kernel]
>> 0xffffffff813bb641 : __generic_unplug_device+0x35/0x39 [kernel]
>> 0xffffffff813bb673 : generic_unplug_device+0x2e/0x3e [kernel]
>> 0xffffffff813b63a6 : blk_unplug+0x48/0x4d [kernel]
>> 0xffffffff813b63bd : blk_backing_dev_unplug+0x12/0x14 [kernel]
>> 0xffffffff8114084f : sync_buffer+0x3e/0x47 [kernel]
>> 0xffffffff81d9b33c : __wait_on_bit+0x4c/0x7e [kernel]
>> 0xffffffff81d9b3dd : out_of_line_wait_on_bit+0x6f/0x7c [kernel]
>> 0xffffffff81140774 : __wait_on_buffer+0x24/0x26 [kernel]
>> 0xffffffff81205523 : wait_on_buffer+0x3d/0x41 [kernel]
>> 0xffffffff81206138 : journal_commit_transaction+0xb42/0x117a [kernel]
>> 0xffffffff8120961a : kjournald+0x102/0x25f [kernel]
>> 0xffffffff81083c43 : kthread+0x9d/0xa5 [kernel]
>> 0xffffffff81030634 : kernel_thread_helper+0x4/0x10 [kernel]
>> 0xffffffff81d9d53c : restore_args+0x0/0x30 [kernel] (inexact)
>> 0xffffffff81083ba6 : kthread+0x0/0xa5 [kernel] (inexact)
>> 0xffffffff81030630 : kernel_thread_helper+0x0/0x10 [kernel] (inexact)
>>
>> ata_scsi_find_dev
>> 0xffffffff816292b1 : ata_scsi_find_dev+0x0/0x39 [kernel]
>> 0xffffffff8162c2b6 : ata_scsi_queuecmd+0x49/0x98 [kernel]
>> 0xffffffff81515625 : scsi_dispatch_cmd+0x1e1/0x25f [kernel]
>> 0xffffffff8151b43b : scsi_request_fn+0x3f2/0x53b [kernel]
>> 0xffffffff813bb641 : __generic_unplug_device+0x35/0x39 [kernel]
>> 0xffffffff813bb673 : generic_unplug_device+0x2e/0x3e [kernel]
>> 0xffffffff813b63a6 : blk_unplug+0x48/0x4d [kernel]
>> 0xffffffff813b63bd : blk_backing_dev_unplug+0x12/0x14 [kernel]
>> 0xffffffff8114084f : sync_buffer+0x3e/0x47 [kernel]
>> 0xffffffff81d9b33c : __wait_on_bit+0x4c/0x7e [kernel]
>> 0xffffffff81d9b3dd : out_of_line_wait_on_bit+0x6f/0x7c [kernel]
>> 0xffffffff81140774 : __wait_on_buffer+0x24/0x26 [kernel]
>> 0xffffffff81205523 : wait_on_buffer+0x3d/0x41 [kernel]
>> 0xffffffff81206138 : journal_commit_transaction+0xb42/0x117a [kernel]
>> 0xffffffff8120961a : kjournald+0x102/0x25f [kernel]
>> 0xffffffff81083c43 : kthread+0x9d/0xa5 [kernel]
>> 0xffffffff81030634 : kernel_thread_helper+0x4/0x10 [kernel]
>> 0xffffffff81d9d53c : restore_args+0x0/0x30 [kernel] (inexact)
>> 0xffffffff81083ba6 : kthread+0x0/0xa5 [kernel] (inexact)
>> 0xffffffff81030630 : kernel_thread_helper+0x0/0x10 [kernel] (inexact)
>>
>> __ata_scsi_find_dev
>> 0xffffffff816291ff : __ata_scsi_find_dev+0x0/0xb2 [kernel]
>> 0xffffffff816292bf : ata_scsi_find_dev+0xe/0x39 [kernel]
>> 0xffffffff8162c2b6 : ata_scsi_queuecmd+0x49/0x98 [kernel]
>> 0xffffffff81515625 : scsi_dispatch_cmd+0x1e1/0x25f [kernel]
>> 0xffffffff8151b43b : scsi_request_fn+0x3f2/0x53b [kernel]
>> 0xffffffff813bb641 : __generic_unplug_device+0x35/0x39 [kernel]
>>
>> which is output by:
>>
>> probe kernel.function("*@drivers/ata/libata*.c") {
>> printf("%s\n", probefunc());
>> print_backtrace();
>> printf("\n");
>> }
>>
>> --
>> Regards,
>> Peter Teoh
>
>
Regards,
Peter Teoh
