commit: http://blackfin.uclinux.org/git/?p=linux-kernel;a=commitdiff;h=355ec92275c5fabc703db9f4c7a95526b5a13d1a branch: http://blackfin.uclinux.org/git/?p=linux-kernel;a=shortlog;h=refs/heads/2012R2
Reported-by: Bob Maris <[email protected]> TWI transfer interrupts may be lost when system is heavily handling other interrupts, while current transfer handler depends on each accurate interrupt and misses some data in this case. Because there are 2 2-byte FIFOs in blackfin TWI controller, the occurrence of the data loss can be reduced by reading till the RX FIFO is empty and writing till the TX FIFO is full. Signed-off-by: Sonic Zhang <[email protected]> --- drivers/i2c/busses/i2c-bfin-twi.c | 47 +++++++++++++++++++++--------------- 1 files changed, 27 insertions(+), 20 deletions(-) diff --git a/drivers/i2c/busses/i2c-bfin-twi.c b/drivers/i2c/busses/i2c-bfin-twi.c index cc93f80..f54d943 100644 --- a/drivers/i2c/busses/i2c-bfin-twi.c +++ b/drivers/i2c/busses/i2c-bfin-twi.c @@ -39,33 +39,40 @@ static void bfin_twi_handle_interrupt(struct bfin_twi_iface *iface, unsigned short mast_stat = read_MASTER_STAT(iface); if (twi_int_status & XMTSERV) { + if (iface->writeNum <= 0) { + /* start receive immediately after complete sending in + * combine mode. + */ + if (iface->cur_mode == TWI_I2C_MODE_COMBINED) + write_MASTER_CTL(iface, + read_MASTER_CTL(iface) | MDIR); + else if (iface->manual_stop) + write_MASTER_CTL(iface, + read_MASTER_CTL(iface) | STOP); + else if (iface->cur_mode == TWI_I2C_MODE_REPEAT && + iface->cur_msg + 1 < iface->msg_num) { + if (iface->pmsg[iface->cur_msg + 1].flags & + I2C_M_RD) + write_MASTER_CTL(iface, + read_MASTER_CTL(iface) | + MDIR); + else + write_MASTER_CTL(iface, + read_MASTER_CTL(iface) & + ~MDIR); + } + } /* Transmit next data */ - if (iface->writeNum > 0) { + while (iface->writeNum > 0 && + (read_FIFO_STAT(iface) & XMTSTAT) != XMT_FULL) { SSYNC(); write_XMT_DATA8(iface, *(iface->transPtr++)); iface->writeNum--; } - /* start receive immediately after complete sending in - * combine mode. - */ - else if (iface->cur_mode == TWI_I2C_MODE_COMBINED) - write_MASTER_CTL(iface, - read_MASTER_CTL(iface) | MDIR); - else if (iface->manual_stop) - write_MASTER_CTL(iface, - read_MASTER_CTL(iface) | STOP); - else if (iface->cur_mode == TWI_I2C_MODE_REPEAT && - iface->cur_msg + 1 < iface->msg_num) { - if (iface->pmsg[iface->cur_msg + 1].flags & I2C_M_RD) - write_MASTER_CTL(iface, - read_MASTER_CTL(iface) | MDIR); - else - write_MASTER_CTL(iface, - read_MASTER_CTL(iface) & ~MDIR); - } } if (twi_int_status & RCVSERV) { - if (iface->readNum > 0) { + while (iface->readNum > 0 && + (read_FIFO_STAT(iface) & RCVSTAT)) { /* Receive next data */ *(iface->transPtr) = read_RCV_DATA8(iface); if (iface->cur_mode == TWI_I2C_MODE_COMBINED) {
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