231,12 → 231,15 |
|
; USB2 scheduler. |
; There are two parts: high-speed pipes and split-transaction pipes. |
; Split-transaction scheduler is currently a stub. |
; |
; High-speed scheduler uses the same algorithm as USB1 scheduler: |
; when adding a pipe, optimize the following quantity: |
; * for every microframe, take all bandwidth scheduled to periodic transfers, |
; * calculate maximum over all microframe, |
; * calculate maximum over all microframes, |
; * select a variant which minimizes that maximum; |
; * if there are several such variants, |
; prefer those that are closer to end of frame |
; to minimize collisions with split transactions; |
; when removing a pipe, do nothing (except for bookkeeping). |
; in: esi -> usb_controller |
; out: edx -> usb_static_ep, eax = S-Mask |
345,11 → 348,13 |
; then the previous optimum, update the optimal bandwidth and the target. |
cmp edi, [.bandwidth] |
ja @f |
jb .update |
cmp ecx, [.targetsmask] |
jb @f |
.update: |
mov [.bandwidth], edi |
mov [.target], edx |
movi eax, 1 |
shl eax, cl |
mov [.targetsmask], eax |
mov [.targetsmask], ecx |
@@: |
; 4k. Loop #2: continue 8 times for every microframe. |
inc ecx |
451,7 → 456,7 |
mov dl, 0xFF |
@@: |
; try all variants edx, edx shl 1, edx shl 2, ... |
; until they fit in the lower byte (8 microframes per frame) |
; while they fit in the lower byte (8 microframes per frame) |
.select_best_mframe: |
xor edi, edi |
mov ecx, edx |
512,8 → 517,6 |
; We do not reorder anything, so just update book-keeping variable |
; in the list header. |
proc ehci_hs_interrupt_list_unlink |
; get target list |
mov edx, [ebx+ehci_pipe.BaseList-sizeof.ehci_pipe] |
movzx eax, word [ebx+ehci_pipe.Token-sizeof.ehci_pipe+2] |
; calculate bandwidth |
call calc_hs_bandwidth |
521,12 → 524,13 |
shr ecx, 30 |
imul eax, ecx |
movzx ecx, byte [ebx+ehci_pipe.Flags-sizeof.ehci_pipe] |
add edx, ehci_static_ep.Bandwidths - ehci_static_ep.SoftwarePart |
; get target list |
mov edx, [ebx+ehci_pipe.BaseList-sizeof.ehci_pipe] |
; update bandwidth |
.dec_bandwidth: |
shr ecx, 1 |
jnc @f |
sub [edx], ax |
sub word [edx+ehci_static_ep.Bandwidths - ehci_static_ep.SoftwarePart], ax |
@@: |
add edx, 2 |
test ecx, ecx |
555,18 → 559,278 |
ret |
endp |
|
uglobal |
ehci_last_fs_alloc dd ? |
endg |
; Split-transaction scheduler (aka TT scheduler, TT stands for Transaction |
; Translator, section 11.14 of the core spec) needs to schedule three event |
; types on two buses: Start-Split and Complete-Split on HS bus and normal |
; transaction on FS/LS bus. |
; Assume that FS/LS bus is more restricted and more important to be scheduled |
; uniformly, so select the variant which minimizes maximal used bandwidth |
; on FS/LS bus and does not overflow HS bus. |
; If there are several such variants, prefer variants which is closest to |
; start of frame, and within the same microframe consider HS bandwidth |
; utilization as a last criteria. |
|
; This needs to be rewritten. Seriously. |
; It schedules everything to the first microframe of some frame, |
; frame is spinned out of thin air. |
; This works while you have one keyboard and one mouse... |
; maybe even ten keyboards and ten mice... but give any serious stress, |
; and this would break. |
proc ehci_select_fs_interrupt_list |
virtual at ebp-12 |
; The procedure ehci_select_tt_interrupt_list has been splitted into several |
; macro, each representing a logical step of the procedure, |
; to simplify understanding what is going on. Consider all the following macro |
; as logical parts of one procedure, they are meaningless outside the context. |
|
; Given a frame, calculate bandwidth occupied by already opened pipes |
; in every microframe. |
; Look for both HS and FS/LS buses: there are 16 words of information, |
; 8 for HS bus, 8 for FS/LS bus, for every microframe. |
; Since we count already opened pipes, the total bandwidth in every microframe |
; is less than 60000 bits (and even 60000*80% bits), otherwise the scheduler |
; would not allow to open those pipes. |
; edi -> first list for the frame |
macro tt_calc_bandwidth_in_frame |
{ |
local .lists, .pipes, .pipes_done, .carry |
; 1. Zero everything. |
xor eax, eax |
mov edx, edi |
repeat 4 |
mov dword [.budget+(%-1)*4], eax |
end repeat |
repeat 4 |
mov dword [.hs_bandwidth+(%-1)*4], eax |
end repeat |
mov [.total_budget], ax |
; Loop over all lists for the given frame. |
.lists: |
; 2. Total HS bandwidth for all pipes in one list is kept inside list header, |
; add it. Note that overflow is impossible, so we may add entire dwords. |
mov ebx, [edx+ehci_static_ep.SoftwarePart+usb_static_ep.NextVirt] |
repeat 4 |
mov eax, dword [edx+ehci_static_ep.Bandwidths+(%-1)*4] |
add dword [.hs_bandwidth+(%-1)*4], eax |
end repeat |
; Loop over all pipes in the given list. |
add edx, ehci_static_ep.SoftwarePart |
.pipes: |
cmp ebx, edx |
jz .pipes_done |
; 3. For every pipe in every list for the given frame: |
; 3a. Check whether the pipe resides on the same FS/LS bus as the new pipe. |
; If not, skip this pipe. |
mov eax, [ebx+usb_pipe.DeviceData] |
mov eax, [eax+usb_device_data.TTHub] |
cmp eax, [.tthub] |
jnz @f |
; 3b. Calculate FS/LS budget for the opened pipe. |
; Note that eax = TTHub after 3a. |
call tt_calc_budget |
; 3c. Update total budget: add the value from 3b |
; to the budget of the first microframe scheduled for this pipe. |
bsf ecx, [ebx+ehci_pipe.Flags-sizeof.ehci_pipe] |
add [.budget+ecx*2], ax |
@@: |
mov ebx, [ebx+usb_pipe.NextVirt] |
jmp .pipes |
.pipes_done: |
mov edx, [edx+ehci_static_ep.NextList-ehci_static_ep.SoftwarePart] |
test edx, edx |
jnz .lists |
; 4. If the budget for some microframe is exceeded, carry it to the following |
; microframe(s). The actual size of one microframe is 187.5 raw bytes; |
; the core spec says that 188 bytes should be scheduled in every microframe. |
xor eax, eax |
xor ecx, ecx |
.carry: |
xor edx, edx |
add ax, [.budget+ecx*2] |
cmp ax, 188 |
jbe @f |
mov dx, ax |
mov ax, 188 |
sub dx, ax |
@@: |
mov [.budget+ecx*2], ax |
add [.total_budget], ax |
mov ax, dx |
inc ecx |
cmp ecx, 8 |
jb .carry |
} |
|
; Checks whether the new pipe fits in the existing FS budget |
; starting from the given microframe. If not, mark the microframe |
; as impossible for scheduling. |
; in: ecx = microframe |
macro tt_exclude_microframe_if_no_budget |
{ |
local .loop, .good, .bad |
; 1. If the new budget plus the current budget does not exceed 188 bytes, |
; the variant is possible. |
mov ax, [.budget+ecx*2] |
mov edx, ecx |
add ax, [.new_budget] |
sub ax, 188 |
jbe .good |
; 2. Otherwise, |
; a) nothing should be scheduled in some following microframes, |
; b) after adding the new budget everything should fit in first 6 microframes, |
; this guarantees that even in the worst case 90% limit is satisfied. |
.loop: |
cmp edx, 5 |
jae .bad |
cmp [.budget+(edx+1)*2], 0 |
jnz .bad |
inc edx |
sub ax, 188 |
ja .loop |
.bad: |
btr [.possible_microframes], ecx |
.good: |
} |
|
; Calculate data corresponding to the particular scheduling variant for the new pipe. |
; Data describe the current scheduling state collected over all frames touched |
; by the given variant: maximal HS bandwidth, maximal FS/LS budget, |
; which microframes fit in the current FS/LS budget for all frames. |
macro tt_calc_statistics_for_one_variant |
{ |
local .frames, .microframes |
; 1. Initialize: zero maximal bandwidth, |
; first 6 microframes are possible for scheduling. |
xor eax, eax |
repeat 4 |
mov dword [.max_hs_bandwidth+(%-1)*4], eax |
end repeat |
mov [.max_fs_bandwidth], ax |
mov [.possible_microframes], 0x3F |
; Loop over all frames starting with [.variant] advancing by [.variant_delta]. |
mov edi, [.variant] |
.frames: |
; 2. Calculate statistics for one frame. |
tt_calc_bandwidth_in_frame |
; 3. Update maximal FS budget. |
mov ax, [.total_budget] |
cmp ax, [.max_fs_bandwidth] |
jb @f |
mov [.max_fs_bandwidth], ax |
@@: |
; 4. For every microframe, update maximal HS bandwidth |
; and check whether the microframe is allowed for scheduling. |
xor ecx, ecx |
.microframes: |
mov ax, [.hs_bandwidth+ecx*2] |
cmp ax, [.max_hs_bandwidth+ecx*2] |
jb @f |
mov [.max_hs_bandwidth+ecx*2], ax |
@@: |
tt_exclude_microframe_if_no_budget |
inc ecx |
cmp ecx, 8 |
jb .microframes |
; Stop loop when outside of first descriptor group. |
lea eax, [esi+ehci_controller.IntEDs+32*sizeof.ehci_static_ep-sizeof.ehci_controller] |
add edi, [.variant_delta] |
cmp edi, eax |
jb .frames |
} |
|
struct usb_split_info |
microframe_mask dd ? ; lower byte is S-mask, second byte is C-mask |
ssplit_bandwidth dd ? |
csplit_bandwidth dd ? |
ends |
|
; Check whether the current variant and the current microframe are allowed |
; for scheduling. If so, check whether they are better than the previously |
; selected variant+microframe, if any. If so, update the previously selected |
; variant+microframe to current ones. |
; ecx = microframe, [.variant] = variant |
macro tt_check_variant_microframe |
{ |
local .nothing, .update, .ssplit, .csplit, .csplit_done |
; 1. If the current microframe does not fit in existing FS budget, do nothing. |
bt [.possible_microframes], ecx |
jnc .nothing |
; 2. Calculate maximal HS bandwidth over all affected microframes. |
; 2a. Start-split phase: one or more microframes starting with ecx, |
; coded in lower byte of .info.microframe_mask. |
xor ebx, ebx |
xor edx, edx |
.ssplit: |
lea eax, [ecx+edx] |
movzx eax, [.max_hs_bandwidth+eax*2] |
add eax, [.info.ssplit_bandwidth] |
cmp ebx, eax |
ja @f |
mov ebx, eax |
@@: |
inc edx |
bt [.info.microframe_mask], edx |
jc .ssplit |
; 2b. Complete-split phase: zero or more microframes starting with |
; ecx+(last start-split microframe)+2, |
; coded in second byte of .info.microframe_mask. |
add edx, 8 |
.csplit: |
inc edx |
bt [.info.microframe_mask], edx |
jnc .csplit_done |
lea eax, [ecx+edx] |
cmp eax, 8 |
jae .csplit_done |
movzx eax, [.max_hs_bandwidth+(eax-8)*2] |
add eax, [.info.csplit_bandwidth] |
cmp ebx, eax |
ja .csplit |
mov ebx, eax |
jmp .csplit |
.csplit_done: |
; 3. Check that current HS bandwidth + new bandwidth <= limit; |
; USB2 specification allows maximum 60000*80% bit times for periodic microframe. |
cmp ebx, 48000 |
ja .nothing |
; 4. This variant is possible for scheduling. |
; Check whether it is better than the currently selected one. |
; 4a. The primary criteria: FS/LS bandwidth. |
mov ax, [.max_fs_bandwidth] |
cmp ax, [.best_fs_bandwidth] |
ja .nothing |
jb .update |
; 4b. The secondary criteria: prefer microframes which are closer to start of frame. |
cmp ecx, [.targetsmask] |
ja .nothing |
jb .update |
; 4c. The last criteria: HS bandwidth. |
cmp ebx, [.bandwidth] |
ja .nothing |
.update: |
; 5. This variant is better than the previously selected. |
; Update the best variant with current data. |
mov [.best_fs_bandwidth], ax |
mov [.bandwidth], ebx |
mov [.targetsmask], ecx |
mov eax, [.variant] |
mov [.target], eax |
.nothing: |
} |
|
; TT scheduler: add new pipe. |
; in: esi -> usb_controller, edi -> usb_pipe |
; out: edx -> usb_static_ep, eax = S-Mask |
proc ehci_select_tt_interrupt_list |
virtual at ebp-12-.local_vars_size |
.local_vars_start: |
.info usb_split_info |
.new_budget dw ? |
.total_budget dw ? |
.possible_microframes dd ? |
.tthub dd ? |
.budget rw 8 |
.hs_bandwidth rw 8 |
.max_hs_bandwidth rw 8 |
.max_fs_bandwidth dw ? |
.best_fs_bandwidth dw ? |
.variant dd ? |
.variant_delta dd ? |
.target_delta dd ? |
.local_vars_size = $ - .local_vars_start |
|
.targetsmask dd ? |
.bandwidth dd ? |
.target dd ? |
578,26 → 842,246 |
.type dd ? |
.interval dd ? |
end virtual |
mov eax, [edi+ehci_pipe.Token-sizeof.ehci_pipe] |
shr eax, 16 |
and eax, (1 shl 11) - 1 |
push ebx edi |
; 1. Compute the real interval. FS/LS devices encode the interval as |
; number of milliseconds. Use the maximal power of two that is not greater than |
; the given interval and EHCI scheduling area = 32 frames. |
cmp [.interval], 1 |
adc [.interval], 0 |
mov ecx, 64 |
mov eax, ecx |
mov eax, 64 * sizeof.ehci_static_ep |
@@: |
shr ecx, 1 |
cmp [.interval], ecx |
jb @b |
mov [.interval], ecx |
; 2. Compute variables for further calculations. |
; 2a. [.variant_delta] is delta between two lists from the first group |
; that correspond to the same variant. |
imul ecx, sizeof.ehci_static_ep |
mov [.variant_delta], ecx |
; 2b. [.target_delta] is delta between the final answer from the group |
; corresponding to [.interval] and the item from the first group. |
sub eax, ecx |
sub eax, ecx |
dec ecx |
and ecx, [ehci_last_fs_alloc] |
inc [ehci_last_fs_alloc] |
add eax, ecx |
imul eax, sizeof.ehci_static_ep |
lea edx, [esi+ehci_controller.IntEDs.SoftwarePart+eax-sizeof.ehci_controller] |
mov ax, 1C01h |
mov [.target_delta], eax |
; 2c. [.variant] is the first list from the first group that corresponds |
; to the current variant. |
lea eax, [esi+ehci_controller.IntEDs-sizeof.ehci_controller] |
mov [.variant], eax |
; 2d. [.tthub] identifies TT hub for new pipe, [.new_budget] is FS budget |
; for new pipe. |
mov eax, [edi+usb_pipe.DeviceData] |
mov eax, [eax+usb_device_data.TTHub] |
mov ebx, edi |
mov [.tthub], eax |
call tt_calc_budget |
mov [.new_budget], ax |
; 2e. [.usb_split_info] describes bandwidth used by new pipe on HS bus. |
lea edi, [.info] |
call tt_fill_split_info |
test eax, eax |
jz .no_bandwidth |
; 2f. There is no best variant yet, put maximal possible values, |
; so any variant would be better than the "current". |
or [.best_fs_bandwidth], -1 |
or [.target], -1 |
or [.bandwidth], -1 |
or [.targetsmask], -1 |
; 3. Loop over all variants, for every variant decide whether it is acceptable, |
; select the best variant from all acceptable variants. |
.check_variants: |
tt_calc_statistics_for_one_variant |
xor ecx, ecx |
.check_microframes: |
tt_check_variant_microframe |
inc ecx |
cmp ecx, 6 |
jb .check_microframes |
add [.variant], sizeof.ehci_static_ep |
dec [.interval] |
jnz .check_variants |
; 4. If there is no acceptable variants, return error. |
mov ecx, [.targetsmask] |
mov edx, [.target] |
cmp ecx, -1 |
jz .no_bandwidth |
; 5. Calculate the answer: edx -> selected list, eax = S-Mask and C-Mask. |
mov eax, [.info.microframe_mask] |
add edx, [.target_delta] |
shl eax, cl |
and eax, 0xFFFF |
; 6. Update HS bandwidths in the selected list. |
xor ecx, ecx |
mov ebx, [.info.ssplit_bandwidth] |
.update_ssplit: |
bt eax, ecx |
jnc @f |
add [edx+ehci_static_ep.Bandwidths+ecx*2], bx |
@@: |
inc ecx |
cmp ecx, 8 |
jb .update_ssplit |
mov ebx, [.info.csplit_bandwidth] |
.update_csplit: |
bt eax, ecx |
jnc @f |
add [edx+ehci_static_ep.Bandwidths+(ecx-8)*2], bx |
@@: |
inc ecx |
cmp ecx, 16 |
jb .update_csplit |
; 7. Return. |
add edx, ehci_static_ep.SoftwarePart |
pop edi ebx |
ret |
.no_bandwidth: |
dbgstr 'Periodic bandwidth limit reached' |
xor eax, eax |
xor edx, edx |
pop edi ebx |
ret |
endp |
|
; Pipe is removing, update the corresponding lists. |
; We do not reorder anything, so just update book-keeping variable |
; in the list header. |
proc ehci_fs_interrupt_list_unlink |
; calculate bandwidth |
push edi |
sub esp, sizeof.usb_split_info |
mov edi, esp |
call tt_fill_split_info |
; get target list |
mov edx, [ebx+ehci_pipe.BaseList-sizeof.ehci_pipe] |
; update bandwidth for Start-Split |
mov eax, [edi+usb_split_info.ssplit_bandwidth] |
xor ecx, ecx |
.dec_bandwidth_1: |
bt [ebx+ehci_pipe.Flags-sizeof.ehci_pipe], ecx |
jnc @f |
sub word [edx+ecx*2+ehci_static_ep.Bandwidths - ehci_static_ep.SoftwarePart], ax |
@@: |
inc ecx |
cmp ecx, 8 |
jb .dec_bandwidth_1 |
; update bandwidth for Complete-Split |
mov eax, [edi+usb_split_info.csplit_bandwidth] |
.dec_bandwidth_2: |
bt [ebx+ehci_pipe.Flags-sizeof.ehci_pipe], ecx |
jnc @f |
sub word [edx+(ecx-8)*2+ehci_static_ep.Bandwidths - ehci_static_ep.SoftwarePart], ax |
@@: |
inc ecx |
cmp ecx, 16 |
jb .dec_bandwidth_2 |
add esp, sizeof.usb_split_info |
pop edi |
ret |
endp |
|
; Helper procedure for ehci_select_tt_interrupt_list. |
; Calculates "best-case budget" according to the core spec, |
; that is, number of bytes (not bits) corresponding to "optimistic" transaction |
; time, including inter-packet delays/bus turn-around time, |
; but without bit stuffing and timers drift. |
; One extra TT-specific delay is added: TT think time from the hub descriptor. |
; Similar to calc_usb1_bandwidth with corresponding changes. |
; eax -> usb_hub with TT, ebx -> usb_pipe |
proc tt_calc_budget |
movzx ecx, [eax+usb_hub.HubCharacteristics] |
shr ecx, 5 |
and ecx, 3 ; 1+ecx = TT think time in FS-bytes |
mov eax, [ebx+ehci_pipe.Token-sizeof.ehci_pipe] |
shr eax, 16 |
and eax, (1 shl 11) - 1 ; get data length |
bt [ebx+ehci_pipe.Token-sizeof.ehci_pipe], 12 |
jc .low_speed |
; Full-speed interrupt IN/OUT: |
; 33 bits for Token packet (8 for SYNC, 24 for token+address, 3 for EOP), |
; 18 bits for bus turn-around, 11 bits for SYNC+EOP in Data packet, |
; 2 bits for inter-packet delay, 19 bits for Handshake packet, |
; 2 bits for another inter-packet delay. 85 bits total, pad to 11 bytes. |
lea eax, [eax+11+ecx+1] |
; 1 byte is minimal TT think time in addition to ecx. |
ret |
.low_speed: |
; Low-speed interrupt IN/OUT: |
; multiply by 8 for LS -> FS, |
; add 85 bytes as in full-speed interrupt and extra 5 bytes for two PRE packets |
; and two hub delays. |
; 1 byte is minimal TT think time in addition to ecx. |
lea eax, [eax*8+90+ecx+1] |
ret |
endp |
|
; Helper procedure for TT scheduler. |
; Calculates Start-Split/Complete-Split masks and HS bandwidths. |
; ebx -> usb_pipe, edi -> usb_split_info |
proc tt_fill_split_info |
; Interrupt endpoints. |
; The core spec says in 5.7.3 "Interrupt Transfer Packet Size Constraints" that: |
; The maximum allowable interrupt data payload size is 64 bytes or less for full-speed. |
; Low-speed devices are limited to eight bytes or less maximum data payload size. |
; This is important for scheduling, it guarantees that in any case transaction fits |
; in two microframes (usually one, two if transaction has started too late in the first |
; microframe), so check it. |
mov eax, [ebx+ehci_pipe.Token-sizeof.ehci_pipe] |
mov ecx, 8 |
bt eax, 12 |
jc @f |
mov ecx, 64 |
@@: |
shr eax, 16 |
and eax, (1 shl 11) - 1 ; get data length |
cmp eax, ecx |
ja .error |
add eax, 3 ; add 3 bytes for other fields in data packet, PID+CRC16 |
; Multiply by 8 for bytes -> bits and then by 7/6 to accomodate bit stuffing; |
; total 28/3 = 9+1/3 |
mov edx, 55555556h |
lea ecx, [eax*9] |
mul edx |
; One start-split, three complete-splits (unless the last is too far, |
; but this is handled by the caller). |
mov eax, [ebx+usb_pipe.LastTD] |
mov [edi+usb_split_info.microframe_mask], 0x1C01 |
; Structure and HS bandwidth of packets depends on the direction. |
bt [eax+ehci_gtd.Token-sizeof.ehci_gtd], 8 |
jc .interrupt_in |
.interrupt_out: |
; Start-Split phase: |
; 77 bits for SPLIT packet (32 for SYNC, 8 for EOP, 32 for data, 5 for bit stuffing), |
; 88 bits for inter-packet delay, 68 bits for Token packet, |
; 88 bits for inter-packet delay, 40 bits for SYNC+EOP in Data packet, |
; 88 bits for last inter-packet delay, total 449 bits. |
lea eax, [edx+ecx+449] |
mov [edi+usb_split_info.ssplit_bandwidth], eax |
; Complete-Split phase: |
; 77 bits for SPLIT packet, |
; 88 bits for inter-packet delay, 68 bits for Token packet, |
; 736 bits for bus turn-around, 49 bits for Handshake packet, |
; 8 bits for inter-packet delay, total 1026 bits. |
mov [edi+usb_split_info.csplit_bandwidth], 1026 |
ret |
.interrupt_in: |
; Start-Split phase: |
; 77 bits for SPLIT packet, 88 bits for inter-packet delay, |
; 68 bits for Token packet, 88 bits for another inter-packet delay, |
; total 321 bits. |
mov [edi+usb_split_info.ssplit_bandwidth], 321 |
; Complete-Split phase: |
; 77 bits for SPLIT packet, 88 bits for inter-packet delay, |
; 68 bits for Token packet, 736 bits for bus turn-around, |
; 40 bits for SYNC+EOP in Data packet, 8 bits for inter-packet delay, |
; total 1017 bits. |
lea eax, [edx+ecx+1017] |
mov [edi+usb_split_info.csplit_bandwidth], eax |
ret |
.error: |
xor eax, eax |
ret |
endp |