scottk/OpenCellular
1
0
Fork 0
mirror of https://github.com/Telecominfraproject/OpenCellular.git synced 2026-01-14 16:46:23 +00:00
Code Issues Packages Projects Releases Wiki Activity

npcx: CEC: Respect the present initiator free-time

Browse Source 
When sending multiple frames, the free-time is a bit
higher to make it easier for other senders to get
a chance to send.

Signed-off-by: Stefan Adolfsson <sadolfsson@chromium.org>

BUG=b:76467407
BRANCH=none
TEST=none
CQ-DEPEND=CL:1030370

Change-Id: I19e510ec0b6e987e0d8477fa5549e0b29ef594ee
Reviewed-on: https://chromium-review.googlesource.com/1030371
Commit-Ready: Stefan Adolfsson <sadolfsson@chromium.org>
Tested-by: Stefan Adolfsson <sadolfsson@chromium.org>
Reviewed-by: Randall Spangler <rspangler@chromium.org>
This commit is contained in:
Stefan Adolfsson
2018-05-06 20:19:37 +02:00
committed by chrome-bot
parent ad01d0518b
commit 64cf05b7e8
1 changed files with 17 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

20
chip/npcx/cec.c
View File

@@ -53,10 +53,15 @@
#error "Buffer size must not exceed 255 since offsets are uint8_t"
#endif
/* Free time timing (us). */
/*
* Free time timing (us). Our free-time is calculated from the end of
* the last bit (not from the start). We compensate by having one
* free-time period less than in the spec.
*/
#define NOMINAL_BIT_TIME APB1_TICKS(2400)
#define FREE_TIME_RS (3 * (NOMINAL_BIT_TIME)) /* Resend */
#define FREE_TIME_NI (5 * (NOMINAL_BIT_TIME)) /* New initiator */
#define FREE_TIME_RS (2 * (NOMINAL_BIT_TIME)) /* Resend */
#define FREE_TIME_NI (4 * (NOMINAL_BIT_TIME)) /* New initiator */
#define FREE_TIME_PI (6 * (NOMINAL_BIT_TIME)) /* Present initiator */
/* Start bit timing (us) */
#define START_BIT_LOW APB1_TICKS(3700)
@@ -231,6 +236,11 @@ struct cec_tx {
uint8_t resends;
/* Acknowledge received from sink? */
uint8_t ack;
/*
* When sending multiple concurrent frames,
* the free-time is slightly higher
*/
int present_initiator;
};
/* Single state for CEC. We are INITIATOR, FOLLOWER or IDLE */
@@ -497,10 +507,13 @@ void enter_state(enum cec_state new_state)
cap_edge = CAP_EDGE_FALLING;
if (cec_tx.resends)
timeout = FREE_TIME_RS;
else if (cec_tx.present_initiator)
timeout = FREE_TIME_PI;
else
timeout = FREE_TIME_NI;
break;
case CEC_STATE_INITIATOR_START_LOW:
cec_tx.present_initiator = 1;
cec_tx.msgt.bit = 0;
cec_tx.msgt.byte = 0;
gpio = 0;
@@ -561,6 +574,7 @@ void enter_state(enum cec_state new_state)
timeout = NOMINAL_BIT_TIME - NOMINAL_SAMPLE_TIME;
break;
case CEC_STATE_FOLLOWER_START_LOW:
cec_tx.present_initiator = 0;
cap_edge = CAP_EDGE_RISING;
timeout = CAP_START_LOW;
break;