diff options
| author | Julius Werner <jwerner@chromium.org> | 2016-10-03 12:52:55 -0700 |
|---|---|---|
| committer | Patrick Georgi <pgeorgi@google.com> | 2016-10-07 17:55:47 +0200 |
| commit | 93b51e7ac9242738a9e3354661ea7a9980938e0a (patch) | |
| tree | fe0274956f49ba5ad65fe13a2b01e4abea6eee0f /src/ec/google/chromeec | |
| parent | e06a1b895c9905c53faaacf9286bafea7a3ef921 (diff) | |
ec/google/chromeec: Add minimum delay between SPI CS assertions
Some Chrome OS ECs require a small amount of time after a SPI
transaction to reset their controllers before they can service the next
CS assertion. The kernel and depthcharge have always enforced a 200us
minimum delay for this... coreboot should've done the same.
BRANCH=gru
BUG=chrome-os-partner:58046
TEST=Booted Kevin in recovery mode, confirmed that recovery events got
logged with correct timestamps in eventlog.
Change-Id: I32ec343f3293ac93729d3e6e2f43d7605a396cdb
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: b9e4696533d4318ae7c8715b71ab963d8897c16c
Original-Change-Id: I6a7baf7859d5d50e299495d118e7890dcaa2c1b0
Original-Signed-off-by: Julius Werner <jwerner@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/392206
Original-Tested-by: Shawn N <shawnn@chromium.org>
Original-Reviewed-by: Shawn N <shawnn@chromium.org>
Reviewed-on: https://review.coreboot.org/16885
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>
Diffstat (limited to 'src/ec/google/chromeec')
| -rw-r--r-- | src/ec/google/chromeec/ec_spi.c | 32 |
1 files changed, 21 insertions, 11 deletions
diff --git a/src/ec/google/chromeec/ec_spi.c b/src/ec/google/chromeec/ec_spi.c index e93d038213..a0049c6860 100644 --- a/src/ec/google/chromeec/ec_spi.c +++ b/src/ec/google/chromeec/ec_spi.c @@ -20,6 +20,11 @@ #include <spi-generic.h> #include <timer.h> +/* This is assuming that this driver is not used on x86. If that changes, this + might need to become a CAR_GLOBAL or maybe even more complicated. */ +static struct stopwatch cs_cooldown_sw; +static const long cs_cooldown_us = 200; + static const uint8_t EcFramingByte = 0xec; #define PROTO3_MAX_PACKET_SIZE 268 @@ -44,7 +49,10 @@ void *crosec_get_buffer(size_t size, int req) static int crosec_spi_io(size_t req_size, size_t resp_size, void *context) { struct spi_slave *slave = (struct spi_slave *)context; + int ret = 0; + while (!stopwatch_expired(&cs_cooldown_sw)) + /* Wait minimum delay between CS assertions. */; spi_claim_bus(slave); /* Allow EC to ramp up clock after being awaken. @@ -53,8 +61,8 @@ static int crosec_spi_io(size_t req_size, size_t resp_size, void *context) if (spi_xfer(slave, req_buf, req_size, NULL, 0)) { printk(BIOS_ERR, "%s: Failed to send request.\n", __func__); - spi_release_bus(slave); - return -1; + ret = -1; + goto out; } uint8_t byte; @@ -65,8 +73,8 @@ static int crosec_spi_io(size_t req_size, size_t resp_size, void *context) if (spi_xfer(slave, NULL, 0, &byte, sizeof(byte))) { printk(BIOS_ERR, "%s: Failed to receive byte.\n", __func__); - spi_release_bus(slave); - return -1; + ret = -1; + goto out; } if (byte == EcFramingByte) break; @@ -75,28 +83,30 @@ static int crosec_spi_io(size_t req_size, size_t resp_size, void *context) printk(BIOS_ERR, "%s: Timeout waiting for framing byte.\n", __func__); - spi_release_bus(slave); - return -1; + ret = -1; + goto out; } } if (spi_xfer(slave, NULL, 0, resp_buf, resp_size)) { printk(BIOS_ERR, "%s: Failed to receive response.\n", __func__); - spi_release_bus(slave); - return -1; + ret = -1; } +out: spi_release_bus(slave); - - return 0; + stopwatch_init_usecs_expire(&cs_cooldown_sw, cs_cooldown_us); + return ret; } int google_chromeec_command(struct chromeec_command *cec_command) { static struct spi_slave *slave = NULL; - if (!slave) + if (!slave) { slave = spi_setup_slave(CONFIG_EC_GOOGLE_CHROMEEC_SPI_BUS, CONFIG_EC_GOOGLE_CHROMEEC_SPI_CHIP); + stopwatch_init(&cs_cooldown_sw); + } return crosec_command_proto(cec_command, crosec_spi_io, slave); } |