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Code Issues Releases Wiki Activity

better signal names

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This commit is contained in:
Joerg Hoppe
2019-11-23 10:29:16 +01:00
parent b0cbeb8ad0
commit 4af9053d94
1 changed files with 10 additions and 11 deletions
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21
10.01_base/2_src/pru1/pru1_statemachine_arbitration.c
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@@ -143,7 +143,7 @@ uint8_t sm_arb_worker_none(uint8_t grant_mask) {
as forwarded by other devices from physical CPU
or generated directly by emulated CPU
*/
uint8_t sm_arb_worker_device(uint8_t grant_mask) {
uint8_t sm_arb_worker_device(uint8_t granted_requests_mask) {
if (sm_arb.cpu_request) {
// Emulated CPU memory access: no NPR/NPG/SACK protocol.
// No arbitration, start transaction when bus idle.
@@ -187,23 +187,22 @@ uint8_t sm_arb_worker_device(uint8_t grant_mask) {
// State 1: Wait For GRANT:
// process the requested grant for an open requests.
// "A device may not accept a grant (assert SACK) after it passes the grant"
grant_mask &= (sm_arb.device_request_mask & ~sm_arb.device_forwarded_grant_mask);
if (grant_mask) {
// one of our requests was granted:
// set SACK
uint8_t device_grant_mask = granted_requests_mask & sm_arb.device_request_mask & ~sm_arb.device_forwarded_grant_mask;
if (device_grant_mask) {
// one of our requests was granted: set SACK
// AND simultaneously clear granted requests BR*/NPR
// BIT(5): SACK mask and level
buslatches_setbits(1, (PRIORITY_ARBITRATION_BIT_MASK & sm_arb.device_request_mask) | BIT(5),
~grant_mask | BIT(5))
~device_grant_mask | BIT(5))
;
// clear granted requests internally
sm_arb.device_request_mask &= ~grant_mask;
sm_arb.device_request_mask &= ~device_grant_mask;
// UNIBUS DATA section is indepedent: MSYN, SSYN, BBSY may still be active.
// -> DMA and INTR statemachine must wait for BBSY.
// Arbitrator should remove GRANT now. Data section on Bus still BBSY
sm_arb.grant_bbsy_ssyn_wait_grant_mask = grant_mask;
sm_arb.grant_bbsy_ssyn_wait_grant_mask = device_grant_mask;
// next is State 2: wait for BBSY clear
}
return 0; // no REQUEST, or no GRANT for us, or wait for BG/BPG & BBSY && SSYN
@@ -212,15 +211,15 @@ uint8_t sm_arb_worker_device(uint8_t grant_mask) {
// DMA and INTR:
// "After receiving the negation of BBSY, SSYN and BGn,
// the requesting device asserts BBSY"
if (grant_mask & sm_arb.grant_bbsy_ssyn_wait_grant_mask)
if (granted_requests_mask & sm_arb.grant_bbsy_ssyn_wait_grant_mask)
return 0; // BG*/NPG still set
if (buslatches_getbyte(1) & BIT(6))
return 0; // BBSY still set
if (buslatches_getbyte(4) & BIT(5))
return 0; // SSYN still set
grant_mask = sm_arb.grant_bbsy_ssyn_wait_grant_mask;
granted_requests_mask = sm_arb.grant_bbsy_ssyn_wait_grant_mask;
sm_arb.grant_bbsy_ssyn_wait_grant_mask = 0; // Next State is 1
return grant_mask; // signal what request we got granted.
return granted_requests_mask; // signal what request we got granted.
}
}