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drivers/i2c/tpm/cr50: Clean up locality functions 

Clean up the mask and timeout handling in the locality functions
that were copied from the original driver.

BUG=chrome-os-partner:53336

Change-Id: Ifa1445224b475aec38c2ac56e15cb7ba7fcd21ea
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
This commit is contained in:
Duncan Laurie 2016-09-19 17:09:01 -07:00
parent 6f5ceb26b9
commit 557e1a729a
1 changed files with 20 additions and 19 deletions
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39
src/drivers/i2c/tpm/cr50.c
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@ -137,13 +137,13 @@ static int cr50_i2c_write(struct tpm_chip *chip,
static int check_locality(struct tpm_chip *chip, int loc)
{
uint8_t mask = TPM_ACCESS_VALID | TPM_ACCESS_ACTIVE_LOCALITY;
uint8_t buf;
if (cr50_i2c_read(chip, TPM_ACCESS(loc), &buf, 1) < 0)
return -1;
if ((buf & (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
(TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) {
if ((buf & mask) == mask) {
chip->vendor.locality = loc;
return loc;
}
@ -151,40 +151,41 @@ static int check_locality(struct tpm_chip *chip, int loc)
return -1;
}
static void release_locality(struct tpm_chip *chip, int loc, int force)
static void release_locality(struct tpm_chip *chip, int force)
{
uint8_t mask = TPM_ACCESS_VALID | TPM_ACCESS_REQUEST_PENDING;
uint8_t addr = TPM_ACCESS(chip->vendor.locality);
uint8_t buf;
if (cr50_i2c_read(chip, TPM_ACCESS(loc), &buf, 1) < 0)
if (cr50_i2c_read(chip, addr, &buf, 1) < 0)
return;
if (force || (buf & (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) ==
(TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) {
if (force || (buf & mask) == mask) {
buf = TPM_ACCESS_ACTIVE_LOCALITY;
cr50_i2c_write(chip, TPM_ACCESS(loc), &buf, 1);
cr50_i2c_write(chip, addr, &buf, 1);
}
chip->vendor.locality = 0;
}
static int request_locality(struct tpm_chip *chip, int loc)
{
uint8_t buf = TPM_ACCESS_REQUEST_USE;
struct stopwatch sw;
if (check_locality(chip, loc) >= 0)
return loc; /* we already have the locality */
return loc;
if (cr50_i2c_write(chip, TPM_ACCESS(loc), &buf, 1) < 0)
return -1;
/* wait for burstcount */
int timeout = 2 * 1000; /* 2s timeout */
while (timeout) {
if (check_locality(chip, loc) >= 0)
return loc;
mdelay(TPM_TIMEOUT);
timeout--;
stopwatch_init_msecs_expire(&sw, CR50_TIMEOUT_LONG_MS);
while (check_locality(chip, loc) < 0) {
if (stopwatch_expired(&sw))
return -1;
mdelay(CR50_TIMEOUT_SHORT_MS);
}
return -1;
return loc;
}
/* cr50 requires all 4 bytes of status register to be read */
@ -458,11 +459,11 @@ int tpm_vendor_init(struct tpm_chip *chip, unsigned bus, uint32_t dev_addr)
return 0;
out_err:
release_locality(chip, 0, 1);
release_locality(chip, 1);
return -1;
}
void tpm_vendor_cleanup(struct tpm_chip *chip)
{
release_locality(chip, chip->vendor.locality, 1);
release_locality(chip, 1);
}