Re: [PATCH] ide: hdio.txt update
From: Tejun Heo
Date: Wed Mar 02 2005 - 22:28:25 EST
Hello, again.
I've updated descriptions regarding SELECT register.
Signed-off-by: Tejun Heo <htejun@xxxxxxxxx>
Index: linux-taskfile-ng/Documentation/ioctl/hdio.txt
===================================================================
--- linux-taskfile-ng.orig/Documentation/ioctl/hdio.txt 2005-03-03 11:14:43.551189244 +0900
+++ linux-taskfile-ng/Documentation/ioctl/hdio.txt 2005-03-03 11:15:14.593283052 +0900
@@ -573,26 +573,31 @@ HDIO_DRIVE_TASKFILE execute raw taskfil
EFAULT req_cmd == TASKFILE_IN_OUT (not implemented as of 2.6.8)
EPERM req_cmd == TASKFILE_MULTI_OUT and drive
multi-count not yet set.
-
+ EIO Drive failed the command.
notes:
- [1] Currently (2.6.8), both the input and output buffers are
- copied from the user and written back to the user, even when
- not used. This may be a bug.
-
- [2] The out_flags and in_flags are returned to the user after
- the ioctl completes. Currently (2.6.8) these are the same
- as the input values, unchanged. In the future, they may have
- more significance.
-
- Extreme caution should be used with using this ioctl. A
- mistake can easily corrupt data or hang the system.
-
- The argument to the ioctl is a pointer to a region of memory
- containing a ide_task_request_t structure, followed by an
- optional buffer of data to be transmitted to the drive,
- followed by an optional buffer to receive data from the drive.
+ [1] READ THE FOLLOWING NOTES *CAREFULLY*. THIS IOCTL IS
+ FULL OF GOTCHAS. Extreme caution should be used with using
+ this ioctl. A mistake can easily corrupt data or hang the
+ system.
+
+ [2] Both the input and output buffers are copied from the
+ user and written back to the user, even when not used. The
+ out_flags and in_flags are written back to the user after
+ the ioctl completes. These are the same as the input
+ values, unchanged.
+
+ [3] The default value of SELECT is (0xa0|DEV_bit|LBA_bit)
+ except for four drives per port chipsets. For four drives
+ per port chipsets, it's (0xa0|DEV_bit|LBA_bit) for the first
+ pair and (0x80|DEV_bit|LBA_bit) for the second pair.
+
+ [4] The argument to the ioctl is a pointer to a region of
+ memory containing a ide_task_request_t structure, followed
+ by an optional buffer of data to be transmitted to the
+ drive, followed by an optional buffer to receive data from
+ the drive.
Command is passed to the disk drive via the ide_task_request_t
structure, which contains these fields:
@@ -611,11 +616,66 @@ HDIO_DRIVE_TASKFILE execute raw taskfil
out_size output (user->drive) buffer size, bytes
in_size input (drive->user) buffer size, bytes
- This ioctl does not necessarily respect all flags in the
- out_flags and in_flags values -- some taskfile registers
- may be written or read even if not requested in the flags.
- Unused fields of io_ports[] and hob_ports[] should be set
- to zero.
+ When out_flags is zero, the following registers are loaded.
+
+ HOB_FEATURE If the drive supports LBA48
+ HOB_NSECTOR If the drive supports LBA48
+ HOB_SECTOR If the drive supports LBA48
+ HOB_LCYL If the drive supports LBA48
+ HOB_HCYL If the drive supports LBA48
+ FEATURE
+ NSECTOR
+ SECTOR
+ LCYL
+ HCYL
+ SELECT First, masked with 0xE0 if LBA48, 0xEF
+ otherwise; then, or'ed with the default
+ value of SELECT.
+
+ If any bit in out_flags is set, the following registers are loaded.
+
+ HOB_DATA If tf_out_flags.b.data is set. HOB_DATA
+ will travel on DD8-DD15 on little endian
+ machines and on DD0-DD7 on big endian machines.
+ DATA If tf_out_flags.b.data is set. DATA will
+ travel on DD0-DD7 on little endian machines
+ and on DD8-DD15 on big endian machines.
+ HOB_NSECTOR If tf_out_flags.b.nsector_hob is set
+ HOB_SECTOR If tf_out_flags.b.sector_hob is set
+ HOB_LCYL If tf_out_flags.b.lcyl_hob is set
+ HOB_HCYL If tf_out_flags.b.hcyl_hob is set
+ FEATURE If tf_out_flags.b.feature is set
+ NSECTOR If tf_out_flags.b.nsector is set
+ SECTOR If tf_out_flags.b.sector is set
+ LCYL If tf_out_flags.b.lcyl is set
+ HCYL If tf_out_flags.b.hcyl is set
+ SELECT Or'ed with the default value of SELECT and
+ loaded regardless of tf_out_flags.b.select.
+
+ Taskfile registers are read back from the drive into
+ {io|hob}_ports[] after the command completes iff one of the
+ following conditions is met; otherwise, the original values
+ will be written back, unchanged.
+
+ 1. The drive fails the command (EIO).
+ 2. More than one bit is set in tf_out_flags.
+ 3. The requested data_phase is TASKFILE_NO_DATA.
+
+ HOB_DATA If tf_in_flags.b.data is set. It will
+ contain DD8-DD15 on little endian machines
+ and DD0-DD7 on big endian machines.
+ DATA If tf_in_flags.b.data is set. It will
+ contain DD0-DD7 on little endian machines
+ and DD8-DD15 on big endian machines.
+ HOB_FEATURE If the drive supports LBA48
+ HOB_NSECTOR If the drive supports LBA48
+ HOB_SECTOR If the drive supports LBA48
+ HOB_LCYL If the drive supports LBA48
+ HOB_HCYL If the drive supports LBA48
+ NSECTOR
+ SECTOR
+ LCYL
+ HCYL
The data_phase field describes the data transfer to be
performed. Value is one of:
@@ -626,27 +686,30 @@ HDIO_DRIVE_TASKFILE execute raw taskfil
TASKFILE_MULTI_OUT
TASKFILE_IN_OUT
TASKFILE_IN_DMA
- TASKFILE_IN_DMAQ
+ TASKFILE_IN_DMAQ == IN_DMA (queueing not supported)
TASKFILE_OUT_DMA
- TASKFILE_OUT_DMAQ
- TASKFILE_P_IN
- TASKFILE_P_IN_DMA
- TASKFILE_P_IN_DMAQ
- TASKFILE_P_OUT
- TASKFILE_P_OUT_DMA
- TASKFILE_P_OUT_DMAQ
+ TASKFILE_OUT_DMAQ == OUT_DMA (queueing not supported)
+ TASKFILE_P_IN unimplemented
+ TASKFILE_P_IN_DMA unimplemented
+ TASKFILE_P_IN_DMAQ unimplemented
+ TASKFILE_P_OUT unimplemented
+ TASKFILE_P_OUT_DMA unimplemented
+ TASKFILE_P_OUT_DMAQ unimplemented
The req_cmd field classifies the command type. It may be
one of:
IDE_DRIVE_TASK_NO_DATA
- IDE_DRIVE_TASK_SET_XFER
+ IDE_DRIVE_TASK_SET_XFER unimplemented
IDE_DRIVE_TASK_IN
- IDE_DRIVE_TASK_OUT
+ IDE_DRIVE_TASK_OUT unimplemented
IDE_DRIVE_TASK_RAW_WRITE
-
-
+ [5] Do not access {in|out}_flags->all except for resetting
+ all the bits. Always access individual bit fields. ->all
+ value will flip depending on endianess. For the same
+ reason, do not use IDE_{TASKFILE|HOB}_STD_{OUT|IN}_FLAGS
+ constants defined in hdreg.h.
@@ -663,7 +726,13 @@ HDIO_DRIVE_CMD execute a special drive
inputs:
- Taskfile register values:
+ Commands other than WIN_SMART
+ args[0] COMMAND
+ args[1] NSECTOR
+ args[2] FEATURE
+ args[3] NSECTOR
+
+ WIN_SMART
args[0] COMMAND
args[1] SECTOR
args[2] FEATURE
@@ -682,11 +751,28 @@ HDIO_DRIVE_CMD execute a special drive
error returns:
EACCES Access denied: requires CAP_SYS_RAWIO
ENOMEM Unable to allocate memory for task
+ EIO Drive reports error
notes:
- Taskfile registers IDE_LCYL, IDE_HCYL, and IDE_SELECT are
- set to zero before executing the command.
+ [1] For commands other than WIN_SMART, args[1] should equal
+ args[3]. SECTOR, LCYL and HCYL are undefined. For
+ WIN_SMART, 0x4f and 0xc2 are loaded into LCYL and HCYL
+ respectively. In both cases SELECT will contain the default
+ value for the drive. Please refer to HDIO_DRIVE_TASKFILE
+ notes for the default value of SELECT.
+
+ [2] If NSECTOR value is greater than zero and the drive sets
+ DRQ when interrupting for the command, NSECTOR * 512 bytes
+ are read from the device into the area following NSECTOR.
+ In the above example, the area would be
+ args[4..4+XFER_SIZE]. 16bit PIO is used regardless of
+ HDIO_SET_32BIT setting.
+
+ [3] If COMMAND == WIN_SETFEATURES && FEATURE == SETFEATURES_XFER
+ && NSECTOR >= XFER_SW_DMA_0 && the drive supports any DMA
+ mode, IDE driver will try to tune the transfer mode of the
+ drive accordingly.
@@ -726,7 +812,14 @@ HDIO_DRIVE_TASK execute task and speci
error returns:
EACCES Access denied: requires CAP_SYS_RAWIO
ENOMEM Unable to allocate memory for task
+ ENOMSG Device is not a disk drive.
+ EIO Drive failed the command.
+
+ notes:
+ [1] DEV bit (0x10) of SELECT register is ignored and the
+ appropriate value for the drive is used. All other bits
+ are used unaltered.
-
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