Total rewrite of the dataphase sections of the sequencer. This was done
to replace the very poor, original implementation of Scatter/Gather operations. Use a bit (that was freed up with the rewrite above) in the SCB control byte to designate commands that should allow disconnection. The kernel driver makes this decision now instead of the sequencer since the sequencer can't do the indexing very efficiently. This commit drops the sequencer from 426 instructions to 390 most likely freeing enough space to do a target mode implementation.
This commit is contained in:
Justin T. Gibbs
parent
e20b74fb9e
commit
71fb7601c2
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=9928
@ -43,7 +43,7 @@
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VERSION AIC7XXX_SEQ_VER "$Id: aic7xxx.seq,v 1.18 1995/07/31 08:21:59 gibbs Exp $"
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SCBMASK = 0x1f
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SCBMASK = 0xff
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SCSISEQ = 0x00
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ENRSELI = 0x10
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@ -64,6 +64,7 @@ SELDO = 0x40
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SELDI = 0x20
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CLRSINT1 = 0x0c
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SSTAT1 = 0x0c
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PHASEMIS = 0x10
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SIMODE1 = 0x11
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SCSIBUSL = 0x12
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SHADDR = 0x14
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@ -99,18 +100,19 @@ SCSICONF_A = 0x5a
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SCSICONF_B = 0x5b
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# The two reserved bytes at SCBARRAY+1[23] are expected to be set to
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# zero, and the reserved bit in SCBARRAY+0 is used as an internal flag
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# to indicate whether or not to reload scatter-gather parameters after
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# a disconnect. We also use bits 6 & 7 to indicate whether or not to
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# initiate SDTR or WDTR repectively when starting this command.
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# zero. Bit 3 in SCBARRAY+0 is used as an internal flag to indicate
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# whether or not to DMA an SCB from host ram. This flag prevents the
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# "re-fetching" of transactions that are requed because the target is
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# busy with another command. We also use bits 6 & 7 to indicate whether
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# or not to initiate SDTR or WDTR repectively when starting this command.
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#
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SCBARRAY+0 = 0xa0
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DISCONNECTED = 0x04
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NEEDDMA = 0x08
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SG_LOAD = 0x10
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NEEDSDTR = 0x10
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TAG_ENB = 0x20
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NEEDSDTR = 0x40
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DISCENB = 0x40
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NEEDWDTR = 0x80
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SCBARRAY+1 = 0xa1
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@ -170,11 +172,11 @@ IMMEDDONE = 0xb1
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# scratchspace (actually a value that can be copied directly into
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# SCSIRATE). The kernel driver will enable synchronous negotiation
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# for all targets that have a value other than 0 in the lower four
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# bits of the target scratch space. This should work irregardless of
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# whether the bios has been installed. NEEDWDTR and NEEDSDTR are the top
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# two bits of the SCB control byte. The kernel driver will set these
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# when a WDTR or SDTR message should be sent to the target the SCB's
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# command references.
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# bits of the target scratch space. This should work regardless of
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# whether the bios has been installed. NEEDSDTR and NEEDWDTR are the
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# fouth and sevent bits of the SCB control byte. The kernel driver
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# will set these when a WDTR or SDTR message should be sent to the
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# target the SCB's command references.
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#
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# REJBYTE contains the first byte of a MESSAGE IN message, so the driver
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# can report an intelligible error if a message is rejected.
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@ -185,9 +187,9 @@ IMMEDDONE = 0xb1
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# no idea what the lun is, and we can't select the right SCB register
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# bank, so force a kernel panic if the target attempts a data in/out or
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# command phase instead of corrupting something. FLAGS also contains
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# configuration bits so that we can optimize for TWIN and WIDE controllers
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# as well as the MAX_OFFSET bit which we set when we want to negotiate for
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# maximum sync offset irregardless of what the per target scratch space says.
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# configuration bits so that we can optimize for TWIN and WIDE controllers,
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# the MAX_OFFSET bit which we set when we want to negotiate for maximum sync
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# offset irregardless of what the per target scratch space says.
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#
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# Note that SG_NEXT occupies four bytes.
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#
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@ -215,9 +217,9 @@ SIGSTATE = 0x4b # value written to SCSISIGO
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# Linux users should use 0xc (12) for SG_SIZEOF
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SG_SIZEOF = 0x8 # sizeof(struct ahc_dma)
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#SG_SIZEOF = 0xc # sizeof(struct scatterlist)
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SCB_SIZEOF = 0x13 # sizeof SCB to DMA (19 bytes)
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SCB_SIZEOF = 0x1a # sizeof SCB to DMA (26 bytes)
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SG_NOLOAD = 0x4c # load SG pointer/length?
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DMAPARAMS = 0x4c # Parameters for DMA
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SG_COUNT = 0x4d # working value of SG count
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SG_NEXT = 0x4e # working value of SG pointer
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SG_NEXT+0 = 0x4e
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@ -229,6 +231,7 @@ SCBCOUNT = 0x52 # the actual number of SCBs
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FLAGS = 0x53 # Device configuration flags
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TWIN_BUS = 0x01
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WIDE_BUS = 0x02
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DPHASE = 0x04
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MAX_OFFSET = 0x08
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ACTIVE_MSG = 0x20
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IDENTIFY_SEEN = 0x40
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@ -242,7 +245,6 @@ ACTIVE_B = 0x55
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SAVED_TCL = 0x56 # Temporary storage for the
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# target/channel/lun of a
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# reconnecting target
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# After starting the selection hardware, we return to the "poll_for_work"
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# loop so that we can check for reconnecting targets as well as for our
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# selection to complete just in case the reselection wins bus arbitration.
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@ -309,11 +311,10 @@ test SCBARRAY+0,NEEDDMA jz test_busy
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# Copy the SCB from the FIFO to the SCBARRAY
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mvi DINDEX, SCBARRAY+0
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call bcopy_3_dfdat
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call bcopy_4_dfdat
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call bcopy_4_dfdat
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call bcopy_4_dfdat
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call bcopy_4_dfdat
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call bcopy_5_dfdat
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call bcopy_7_dfdat
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call bcopy_7_dfdat
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call bcopy_7_dfdat
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# See if there is not already an active SCB for this target. This code
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# locks out on a per target basis instead of target/lun. Although this
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@ -330,7 +331,7 @@ test_busy:
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test SCBARRAY+1,0x88 jz test_a # Id < 8 && A channel
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test ACTIVE_B,A jnz requeue
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test SCBARRAY+0,0x20 jnz start_scb
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test SCBARRAY+0,TAG_ENB jnz start_scb
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or ACTIVE_B,A # Mark the current target as busy
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jmp start_scb
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@ -346,7 +347,7 @@ start_waiting:
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test_a:
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test ACTIVE_A,A jnz requeue
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test SCBARRAY+0,0x20 jnz start_scb
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test SCBARRAY+0,TAG_ENB jnz start_scb
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or ACTIVE_A,A # Mark the current target as busy
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start_scb:
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@ -364,8 +365,7 @@ start_scb:
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start_selection:
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or SCSISEQ,0x48 # ENSELO|ENAUTOATNO
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mov WAITING_SCBH, SCBPTR
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clr SG_NOLOAD
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and FLAGS,0x3f # !RESELECTING
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and FLAGS,0x3f # !RESELECTING
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# As soon as we get a successful selection, the target should go
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# into the message out phase since we have ATN asserted. Prepare
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@ -387,14 +387,14 @@ start_selection:
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jmp wait_for_selection
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identify:
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mov SCBARRAY+1 call disconnect # disconnect ok?
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and A,DISCENB,SCBARRAY+0 # mask off disconnect privledge
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and SINDEX,0x7,SCBARRAY+1 # lun
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or SINDEX,A # return value from disconnect
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or SINDEX,A # or in disconnect privledge
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or SINDEX,0x80 call mk_mesg # IDENTIFY message
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mov A,SINDEX
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test SCBARRAY+0,0xe0 jz !message # WDTR, SDTR or TAG??
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test SCBARRAY+0,0xb0 jz !message # WDTR, SDTR or TAG??
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cmp MSG_START+0,A jne !message # did driver beat us?
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# Tag Message if Tag enabled in SCB control block. Use SCBPTR as the tag
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@ -470,78 +470,118 @@ ITloop:
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p_dataout:
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mvi 0 call scsisig # !CDO|!IOO|!MSGO
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call assert
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call sg_load
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mvi DINDEX,HADDR
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mvi SCBARRAY+19 call bcopy_4
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# mvi DINDEX,HCNT # implicit since HCNT is next to HADDR
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mvi SCBARRAY+23 call bcopy_3
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mvi DINDEX,STCNT
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mvi SCBARRAY+23 call bcopy_3
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# If we are the last SG block, don't set wideodd.
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test SCBARRAY+18,0xff jnz p_dataout_wideodd
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mvi 0x3d call dma # SCSIEN|SDMAEN|HDMAEN|
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mvi DMAPARAMS,0x7d # WIDEODD|SCSIEN|SDMAEN|HDMAEN|
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# DIRECTION|FIFORESET
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jmp p_dataout_rest
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jmp data_phase_init
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p_dataout_wideodd:
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mvi 0xbd call dma # WIDEODD|SCSIEN|SDMAEN|HDMAEN|
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# DIRECTION|FIFORESET
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p_dataout_rest:
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# After a DMA finishes, save the final transfer pointer and count
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# back into the SCB, in case a device disconnects in the middle of
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# a transfer. Use SHADDR and STCNT instead of HADDR and HCNT, since
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# it's a reflection of how many bytes were transferred on the SCSI
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# (as opposed to the host) bus.
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#
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mvi DINDEX,SCBARRAY+23
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mvi STCNT call bcopy_3
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mvi DINDEX,SCBARRAY+19
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mvi SHADDR call bcopy_4
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call sg_advance
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mov SCBARRAY+18,SG_COUNT # residual S/G count
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jmp ITloop
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# If we re-enter the data phase after going through another phase, the
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# STCNT may have been cleared, so restore it from the residual field.
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data_phase_reinit:
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mvi DINDEX, STCNT
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mvi SCBARRAY+15 call bcopy_3
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jmp data_phase_loop
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# Reads should not use WIDEODD since it may make the last byte for a SG segment
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# go to the next segment.
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p_datain:
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mvi 0x40 call scsisig # !CDO|IOO|!MSGO
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mvi DMAPARAMS,0x39 # SCSIEN|SDMAEN|HDMAEN|
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# !DIRECTION|FIFORESET
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data_phase_init:
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call assert
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call sg_load
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test FLAGS, DPHASE jnz data_phase_reinit
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call sg_scb2ram
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or FLAGS, DPHASE # We have seen a data phase
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data_phase_loop:
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# If we are the last SG block, don't set wideodd.
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cmp SG_COUNT,0x01 jne data_phase_wideodd
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and DMAPARAMS, 0xbf # Turn off WIDEODD
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data_phase_wideodd:
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mov DMAPARAMS call dma
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# Exit if we had an underrun
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test SSTAT0,0x04 jz data_phase_finish # underrun STCNT != 0
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# Advance the scatter-gather pointers if needed
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#
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sg_advance:
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dec SG_COUNT # one less segment to go
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test SG_COUNT, 0xff jz data_phase_finish #Are we done?
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clr A # add sizeof(struct scatter)
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add SG_NEXT+0,SG_SIZEOF,SG_NEXT+0
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adc SG_NEXT+1,A,SG_NEXT+1
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adc SG_NEXT+2,A,SG_NEXT+2
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adc SG_NEXT+3,A,SG_NEXT+3
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# Load a struct scatter and set up the data address and length.
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# If the working value of the SG count is nonzero, then
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# we need to load a new set of values.
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#
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# This, like all DMA's, assumes a little-endian host data storage.
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#
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sg_load:
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clr HCNT+2
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clr HCNT+1
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mvi HCNT+0,SG_SIZEOF
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mvi DINDEX,HADDR
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mvi SCBARRAY+19 call bcopy_4
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mvi SG_NEXT call bcopy_4
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# mvi DINDEX,HCNT # implicit since HCNT is next to HADDR
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mvi SCBARRAY+23 call bcopy_3
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mvi DFCNTRL,0xd # HDMAEN|DIRECTION|FIFORESET
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# Wait for DMA from host memory to data FIFO to complete, then disable
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# DMA and wait for it to acknowledge that it's off.
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#
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call dma_finish
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# Copy data from FIFO into SCB data pointer and data count. This assumes
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# that the struct scatterlist has this structure (this and sizeof(struct
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# scatterlist) == 12 are asserted in aic7xxx.c):
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#
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# struct scatterlist {
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# char *address; /* four bytes, little-endian order */
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# ... /* four bytes, ignored */
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# unsigned short length; /* two bytes, little-endian order */
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# }
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#
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# Not in FreeBSD. the scatter list entry is only 8 bytes.
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#
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# struct ahc_dma_seg {
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# physaddr addr; /* four bytes, little-endian order */
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# long len; /* four bytes, little endian order */
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# };
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#
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mvi DINDEX,HADDR
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call bcopy_7_dfdat
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# For Linux, we must throw away four bytes since there is a 32bit gap
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# in the middle of a struct scatterlist
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# call bcopy_4_dfdat
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# mov NONE,DFDAT
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# mov NONE,DFDAT
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# mov NONE,DFDAT
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# mov NONE,DFDAT
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# call bcopy_3_dfdat #Only support 24 bit length.
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# Load STCNT as well. It is a mirror of HCNT
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mvi DINDEX,STCNT
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mvi SCBARRAY+23 call bcopy_3
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mvi HCNT call bcopy_3
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test SSTAT1,PHASEMIS jz data_phase_loop
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# If we are the last SG block, don't set wideodd.
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test SCBARRAY+18,0xff jnz p_datain_wideodd
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mvi 0x39 call dma # SCSIEN|SDMAEN|HDMAEN|
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# !DIRECTION|FIFORESET
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jmp p_datain_rest
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p_datain_wideodd:
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mvi 0xb9 call dma # WIDEODD|SCSIEN|SDMAEN|HDMAEN|
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# !DIRECTION|FIFORESET
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p_datain_rest:
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mvi DINDEX,SCBARRAY+23
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data_phase_finish:
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# After a DMA finishes, save the SG and STCNT residuals back into the SCB
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# We use STCNT instead of HCNT, since it's a reflection of how many bytes
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# were transferred on the SCSI (as opposed to the host) bus.
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#
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mvi DINDEX,SCBARRAY+15
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mvi STCNT call bcopy_3
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mvi DINDEX,SCBARRAY+19
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mvi SHADDR call bcopy_4
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call sg_advance
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mov SCBARRAY+18,SG_COUNT # residual S/G count
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mov SCBARRAY+18, SG_COUNT
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jmp ITloop
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# Command phase. Set up the DMA registers and let 'er rip - the
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@ -552,11 +592,9 @@ p_command:
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mvi 0x80 call scsisig # CDO|!IOO|!MSGO
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call assert
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# Load HADDR and HCNT. We can do this in one bcopy since they are neighbors
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mvi DINDEX,HADDR
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mvi SCBARRAY+7 call bcopy_4
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# mvi DINDEX,HCNT # implicit since HCNT is next to HADDR
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mvi SCBARRAY+11 call bcopy_3
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mvi SCBARRAY+7 call bcopy_7
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mvi DINDEX,STCNT
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mvi SCBARRAY+11 call bcopy_3
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@ -678,9 +716,7 @@ p_mesgin:
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# before the command complete code tried processing it.
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# First check for residuals
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test SCBARRAY+15,0xff jnz resid
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test SCBARRAY+16,0xff jnz resid
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test SCBARRAY+17,0xff jnz resid
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test SCBARRAY+18,0xff jnz resid
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check_status:
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test SCBARRAY+14,0xff jz status_ok # 0 Status?
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@ -690,7 +726,7 @@ check_status:
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status_ok:
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# First, mark this target as free.
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test SCBARRAY+0,0x20 jnz complete # Tagged command
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test SCBARRAY+0,TAG_ENB jnz complete # Tagged command
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and FUNCTION1,0x70,SCBARRAY+1
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mov A,FUNCTION1
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test SCBARRAY+1,0x88 jz clear_a
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@ -774,7 +810,7 @@ p_mesginSDTR:
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p_mesgin2:
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cmp A,4 jne p_mesgin3 # disconnect code?
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or SCBARRAY+0,0x4 # set "disconnected" bit
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or SCBARRAY+0,DISCONNECTED
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jmp p_mesgin_done
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# Save data pointers message? Copy working values into the SCB,
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@ -787,13 +823,15 @@ p_mesgin3:
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jmp p_mesgin_done
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# Restore pointers message? Data pointers are recopied from the
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# SCB anyway at the start of any DMA operation, so the only thing
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# to copy is the scatter-gather values.
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# SCB anytime we enter a data phase for the first time, so all
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# we need to do is clear the DPHASE flag and let the data phase
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# code do the rest.
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#
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p_mesgin4:
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cmp A,3 jne p_mesgin5 # restore pointers code?
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call sg_scb2ram
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and FLAGS,0xfb # !DPHASE we'll reload them
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# the next time through
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jmp p_mesgin_done
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# Identify message? For a reconnecting target, this tells us the lun
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@ -816,8 +854,6 @@ setup_SCB:
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and SCBARRAY+0,0xfb # clear disconnect bit in SCB
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or FLAGS,IDENTIFY_SEEN # make note of IDENTIFY
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call sg_scb2ram # implied restore pointers
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# required on reselect
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jmp ITloop
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get_tag:
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mvi A call inb_first
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@ -885,30 +921,31 @@ p_busfree:
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jmp poll_for_work
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# Instead of a generic bcopy routine that requires an argument, we unroll
|
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# the two cases that are actually used, and call them explicitly. This
|
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# not only reduces the overhead of doing a bcopy by 2/3rds, but ends up
|
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# saving space in the program since you don't have to put the argument
|
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# into the accumulator before the call. Both functions expect DINDEX to
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# contain the destination address and SINDEX to contain the source
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# address.
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# the cases that are actually used, and call them explicitly. This
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# not only reduces the overhead of doing a bcopy, but ends up saving space
|
||||
# in the program since you don't have to put the argument into the accumulator
|
||||
# before the call. Both functions expect DINDEX to contain the destination
|
||||
# address and SINDEX to contain the source address.
|
||||
bcopy_7:
|
||||
mov DINDIR,SINDIR
|
||||
mov DINDIR,SINDIR
|
||||
bcopy_5:
|
||||
mov DINDIR,SINDIR
|
||||
bcopy_4:
|
||||
mov DINDIR,SINDIR
|
||||
bcopy_3:
|
||||
mov DINDIR,SINDIR
|
||||
mov DINDIR,SINDIR
|
||||
mov DINDIR,SINDIR ret
|
||||
|
||||
bcopy_4:
|
||||
mov DINDIR,SINDIR
|
||||
mov DINDIR,SINDIR
|
||||
mov DINDIR,SINDIR
|
||||
mov DINDIR,SINDIR ret
|
||||
|
||||
bcopy_3_dfdat:
|
||||
bcopy_7_dfdat:
|
||||
mov DINDIR,DFDAT
|
||||
mov DINDIR,DFDAT
|
||||
mov DINDIR,DFDAT ret
|
||||
|
||||
bcopy_5_dfdat:
|
||||
mov DINDIR,DFDAT
|
||||
bcopy_4_dfdat:
|
||||
mov DINDIR,DFDAT
|
||||
bcopy_3_dfdat:
|
||||
mov DINDIR,DFDAT
|
||||
mov DINDIR,DFDAT
|
||||
mov DINDIR,DFDAT ret
|
||||
@ -976,7 +1013,6 @@ inb_last1:
|
||||
dma:
|
||||
mov DFCNTRL,SINDEX
|
||||
dma1:
|
||||
dma2:
|
||||
test SSTAT0,0x1 jnz dma3 # DMADONE
|
||||
test SSTAT1,0x10 jz dma1 # PHASEMIS, ie. underrun
|
||||
|
||||
@ -992,19 +1028,14 @@ dma3:
|
||||
dma4:
|
||||
test DFSTATUS,0x1 jz dma4 # !FIFOEMP
|
||||
|
||||
# Now shut the DMA enables off, and copy STCNT (ie. the underrun
|
||||
# amount, if any) to the SCB registers; SG_COUNT will get copied to
|
||||
# the SCB's residual S/G count field after sg_advance is called. Make
|
||||
# sure that the DMA enables are actually off first lest we get an ILLSADDR.
|
||||
# Now shut the DMA enables off and make sure that the DMA enables are
|
||||
# actually off first lest we get an ILLSADDR.
|
||||
#
|
||||
dma5:
|
||||
clr DFCNTRL # disable DMA
|
||||
dma6:
|
||||
test DFCNTRL,0x38 jnz dma6 # SCSIENACK|SDMAENACK|HDMAENACK
|
||||
|
||||
mvi DINDEX,SCBARRAY+15
|
||||
mvi STCNT call bcopy_3
|
||||
|
||||
ret
|
||||
|
||||
dma_finish:
|
||||
@ -1036,10 +1067,9 @@ initialize_for_target:
|
||||
|
||||
mvi SXFRCTL0,0x8a # DFON|SPIOEN|CLRCHN
|
||||
|
||||
# Initialize scatter-gather pointers by setting up the working copy
|
||||
# in scratch RAM.
|
||||
#
|
||||
call sg_scb2ram
|
||||
# Make sure that the system knows we have not been through a DATA
|
||||
# phase.
|
||||
and FLAGS, 0xfb # !DPHASE
|
||||
|
||||
# Initialize SCSIRATE with the appropriate value for this target.
|
||||
#
|
||||
@ -1055,29 +1085,6 @@ assert:
|
||||
|
||||
mvi INTSTAT,NO_IDENT ret # no - cause a kernel panic
|
||||
|
||||
# Find out if disconnection is ok from the information the BIOS has left
|
||||
# us. The tcl from SCBARRAY+1 should be in SINDEX; A will
|
||||
# contain either 0x40 (disconnection ok) or 0x00 (disconnection not ok)
|
||||
# on exit.
|
||||
#
|
||||
# To allow for wide or twin busses, we check the upper bit of the target ID
|
||||
# and the channel ID and look at the appropriate disconnect register.
|
||||
#
|
||||
disconnect:
|
||||
and FUNCTION1,0x70,SINDEX # strip off extra just in case
|
||||
mov A,FUNCTION1
|
||||
test SINDEX, 0x88 jz disconnect_a
|
||||
|
||||
test DISC_DSB_B,A jz disconnect1 # bit nonzero if DISabled
|
||||
clr A ret
|
||||
|
||||
disconnect_a:
|
||||
test DISC_DSB_A,A jz disconnect1 # bit nonzero if DISabled
|
||||
clr A ret
|
||||
|
||||
disconnect1:
|
||||
mvi A,0x40 ret
|
||||
|
||||
# Locate the SCB matching the target ID/channel/lun in SAVED_TCL and switch
|
||||
# the SCB to it. Have the kernel print a warning message if it can't be
|
||||
# found, and generate an ABORT message to the target. SINDEX should be
|
||||
@ -1087,7 +1094,7 @@ findSCB:
|
||||
mov A,SAVED_TCL
|
||||
mov SCBPTR,SINDEX # switch to new SCB
|
||||
cmp SCBARRAY+1,A jne findSCB1 # target ID/channel/lun match?
|
||||
test SCBARRAY+0,0x4 jz findSCB1 # should be disconnected
|
||||
test SCBARRAY+0,DISCONNECTED jz findSCB1 # should be disconnected
|
||||
test SCBARRAY+0,TAG_ENB jnz get_tag
|
||||
ret
|
||||
|
||||
@ -1103,113 +1110,40 @@ findSCB1:
|
||||
call scsisig
|
||||
ret
|
||||
|
||||
# Make a working copy of the scatter-gather parameters in the SCB.
|
||||
# Make a working copy of the scatter-gather parameters from the SCB.
|
||||
#
|
||||
sg_scb2ram:
|
||||
mvi DINDEX,HADDR
|
||||
mvi SCBARRAY+19 call bcopy_7
|
||||
|
||||
mvi DINDEX,STCNT
|
||||
mvi SCBARRAY+23 call bcopy_3
|
||||
|
||||
mov SG_COUNT,SCBARRAY+2
|
||||
|
||||
mvi DINDEX,SG_NEXT
|
||||
mvi SCBARRAY+3 call bcopy_4
|
||||
ret
|
||||
|
||||
mvi SG_NOLOAD,0x80
|
||||
test SCBARRAY+0,0x10 jnz return # don't reload s/g?
|
||||
clr SG_NOLOAD ret
|
||||
|
||||
# Copying RAM values back to SCB, for Save Data Pointers message.
|
||||
# Copying RAM values back to SCB, for Save Data Pointers message, but
|
||||
# only if we've actually been into a data phase to change them. This
|
||||
# protects against bogus data in scratch ram and the residual counts
|
||||
# since they are only initialized when we go into data_in or data_out.
|
||||
#
|
||||
sg_ram2scb:
|
||||
test FLAGS, DPHASE jz return
|
||||
mov SCBARRAY+2,SG_COUNT
|
||||
|
||||
mvi DINDEX,SCBARRAY+3
|
||||
mvi SG_NEXT call bcopy_4
|
||||
|
||||
mvi DINDEX,SCBARRAY+19
|
||||
mvi SHADDR call bcopy_4
|
||||
|
||||
and SCBARRAY+0,0xef,SCBARRAY+0
|
||||
test SG_NOLOAD,0x80 jz return # reload s/g?
|
||||
or SCBARRAY+0,SG_LOAD ret
|
||||
|
||||
# Load a struct scatter if needed and set up the data address and
|
||||
# length. If the working value of the SG count is nonzero, then
|
||||
# we need to load a new set of values.
|
||||
#
|
||||
# This, like the above DMA, assumes a little-endian host data storage.
|
||||
#
|
||||
sg_load:
|
||||
test SG_COUNT,0xff jz return # SG being used?
|
||||
test SG_NOLOAD,0x80 jnz return # don't reload s/g?
|
||||
|
||||
clr HCNT+2
|
||||
clr HCNT+1
|
||||
mvi HCNT+0,SG_SIZEOF
|
||||
|
||||
mvi DINDEX,HADDR
|
||||
mvi SG_NEXT call bcopy_4
|
||||
|
||||
mvi DFCNTRL,0xd # HDMAEN|DIRECTION|FIFORESET
|
||||
|
||||
# Wait for DMA from host memory to data FIFO to complete, then disable
|
||||
# DMA and wait for it to acknowledge that it's off.
|
||||
#
|
||||
|
||||
call dma_finish
|
||||
|
||||
# Copy data from FIFO into SCB data pointer and data count. This assumes
|
||||
# that the struct scatterlist has this structure (this and sizeof(struct
|
||||
# scatterlist) == 12 are asserted in aic7xxx.c):
|
||||
#
|
||||
# struct scatterlist {
|
||||
# char *address; /* four bytes, little-endian order */
|
||||
# ... /* four bytes, ignored */
|
||||
# unsigned short length; /* two bytes, little-endian order */
|
||||
# }
|
||||
#
|
||||
|
||||
# Not in FreeBSD. the scatter list entry is only 8 bytes.
|
||||
#
|
||||
# struct ahc_dma_seg {
|
||||
# physaddr addr; /* four bytes, little-endian order */
|
||||
# long len; /* four bytes, little endian order */
|
||||
# };
|
||||
#
|
||||
|
||||
mvi DINDEX, SCBARRAY+19
|
||||
call bcopy_4_dfdat
|
||||
|
||||
# For Linux, we must throw away four bytes since there is a 32bit gap
|
||||
# in the middle of a struct scatterlist
|
||||
# mov NONE,DFDAT
|
||||
# mov NONE,DFDAT
|
||||
# mov NONE,DFDAT
|
||||
# mov NONE,DFDAT
|
||||
|
||||
call bcopy_3_dfdat #Only support 24 bit length.
|
||||
# Use the residual number since STCNT is corrupted by any message transfer
|
||||
mvi SCBARRAY+15 call bcopy_3
|
||||
ret
|
||||
|
||||
# Advance the scatter-gather pointers only IF NEEDED. If SG is enabled,
|
||||
# and the SCSI transfer count is zero (note that this should be called
|
||||
# right after a DMA finishes), then move the working copies of the SG
|
||||
# pointer/length along. If the SCSI transfer count is not zero, then
|
||||
# presumably the target is disconnecting - do not reload the SG values
|
||||
# next time.
|
||||
#
|
||||
sg_advance:
|
||||
test SG_COUNT,0xff jz return # s/g enabled?
|
||||
|
||||
test STCNT+0,0xff jnz sg_advance1 # SCSI transfer count nonzero?
|
||||
test STCNT+1,0xff jnz sg_advance1
|
||||
test STCNT+2,0xff jnz sg_advance1
|
||||
|
||||
clr SG_NOLOAD # reload s/g next time
|
||||
dec SG_COUNT # one less segment to go
|
||||
|
||||
clr A # add sizeof(struct scatter)
|
||||
add SG_NEXT+0,SG_SIZEOF,SG_NEXT+0
|
||||
adc SG_NEXT+1,A,SG_NEXT+1
|
||||
adc SG_NEXT+2,A,SG_NEXT+2
|
||||
adc SG_NEXT+3,A,SG_NEXT+3 ret
|
||||
|
||||
sg_advance1:
|
||||
mvi SG_NOLOAD,0x80 ret # don't reload s/g next time
|
||||
|
||||
# Add the array base SYNCNEG to the target offset (the target address
|
||||
# is in SCSIID), and return the result in SINDEX. The accumulator
|
||||
# contains the 3->8 decoding of the target ID on return.
|
||||
@ -1231,7 +1165,7 @@ ndx_dtr_2:
|
||||
# reject, you wouldn't be able to tell which message was the culpret.
|
||||
#
|
||||
mk_dtr:
|
||||
test SCBARRAY+0,0xc0 jz return # NEEDWDTR|NEEDSDTR
|
||||
test SCBARRAY+0,0x90 jz return # NEEDWDTR|NEEDSDTR
|
||||
test SCBARRAY+0,NEEDWDTR jnz mk_wdtr_16bit
|
||||
or FLAGS, MAX_OFFSET # Force an offset of 15 or 8 if WIDE
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user