From 5481d0753e7a78bff7550a8165b7924baa74e9cf Mon Sep 17 00:00:00 2001 From: Sonic Zhang Date: Mon, 22 Mar 2010 03:23:18 -0400 Subject: [PATCH] i2c-bfin-twi: fix lost interrupts at high speeds i2c event of next read/write byte may trigger before current int state is cleared in the interrupt handler. So, this should be done at the beginning of interrupt handler to avoid losing new i2c events. Signed-off-by: Sonic Zhang Signed-off-by: Mike Frysinger Signed-off-by: Ben Dooks --- drivers/i2c/busses/i2c-bfin-twi.c | 37 +++++++++++-------------------- 1 file changed, 13 insertions(+), 24 deletions(-) diff --git a/drivers/i2c/busses/i2c-bfin-twi.c b/drivers/i2c/busses/i2c-bfin-twi.c index 0279a7a6b86c..ff61c4b22095 100644 --- a/drivers/i2c/busses/i2c-bfin-twi.c +++ b/drivers/i2c/busses/i2c-bfin-twi.c @@ -81,14 +81,15 @@ static const u16 pin_req[2][3] = { {P_TWI1_SCL, P_TWI1_SDA, 0}, }; -static void bfin_twi_handle_interrupt(struct bfin_twi_iface *iface) +static void bfin_twi_handle_interrupt(struct bfin_twi_iface *iface, + unsigned short twi_int_status) { - unsigned short twi_int_status = read_INT_STAT(iface); unsigned short mast_stat = read_MASTER_STAT(iface); if (twi_int_status & XMTSERV) { /* Transmit next data */ if (iface->writeNum > 0) { + SSYNC(); write_XMT_DATA8(iface, *(iface->transPtr++)); iface->writeNum--; } @@ -110,10 +111,6 @@ static void bfin_twi_handle_interrupt(struct bfin_twi_iface *iface) write_MASTER_CTL(iface, (read_MASTER_CTL(iface) | RSTART) & ~MDIR); } - SSYNC(); - /* Clear status */ - write_INT_STAT(iface, XMTSERV); - SSYNC(); } if (twi_int_status & RCVSERV) { if (iface->readNum > 0) { @@ -135,7 +132,6 @@ static void bfin_twi_handle_interrupt(struct bfin_twi_iface *iface) } else if (iface->manual_stop) { write_MASTER_CTL(iface, read_MASTER_CTL(iface) | STOP); - SSYNC(); } 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) @@ -144,18 +140,12 @@ static void bfin_twi_handle_interrupt(struct bfin_twi_iface *iface) else write_MASTER_CTL(iface, (read_MASTER_CTL(iface) | RSTART) & ~MDIR); - SSYNC(); } - /* Clear interrupt source */ - write_INT_STAT(iface, RCVSERV); - SSYNC(); } if (twi_int_status & MERR) { - write_INT_STAT(iface, MERR); write_INT_MASK(iface, 0); write_MASTER_STAT(iface, 0x3e); write_MASTER_CTL(iface, 0); - SSYNC(); iface->result = -EIO; if (mast_stat & LOSTARB) @@ -173,10 +163,6 @@ static void bfin_twi_handle_interrupt(struct bfin_twi_iface *iface) * results. */ if (twi_int_status & MCOMP) { - write_INT_STAT(iface, MCOMP); - write_INT_MASK(iface, 0); - write_MASTER_CTL(iface, 0); - SSYNC(); /* If it is a quick transfer, only address without data, * not an err, return 1. * If address is acknowledged return 1. @@ -189,8 +175,6 @@ static void bfin_twi_handle_interrupt(struct bfin_twi_iface *iface) return; } if (twi_int_status & MCOMP) { - write_INT_STAT(iface, MCOMP); - SSYNC(); if (iface->cur_mode == TWI_I2C_MODE_COMBINED) { if (iface->readNum == 0) { /* set the read number to 1 and ask for manual @@ -212,7 +196,6 @@ static void bfin_twi_handle_interrupt(struct bfin_twi_iface *iface) /* remove restart bit and enable master receive */ write_MASTER_CTL(iface, read_MASTER_CTL(iface) & ~RSTART); - SSYNC(); } else if (iface->cur_mode == TWI_I2C_MODE_REPEAT && iface->cur_msg+1 < iface->msg_num) { iface->cur_msg++; @@ -231,7 +214,6 @@ static void bfin_twi_handle_interrupt(struct bfin_twi_iface *iface) write_XMT_DATA8(iface, *(iface->transPtr++)); iface->writeNum--; - SSYNC(); } } @@ -249,12 +231,10 @@ static void bfin_twi_handle_interrupt(struct bfin_twi_iface *iface) /* remove restart bit and enable master receive */ write_MASTER_CTL(iface, read_MASTER_CTL(iface) & ~RSTART); - SSYNC(); } else { iface->result = 1; write_INT_MASK(iface, 0); write_MASTER_CTL(iface, 0); - SSYNC(); } } complete(&iface->complete); @@ -265,9 +245,18 @@ static irqreturn_t bfin_twi_interrupt_entry(int irq, void *dev_id) { struct bfin_twi_iface *iface = dev_id; unsigned long flags; + unsigned short twi_int_status; spin_lock_irqsave(&iface->lock, flags); - bfin_twi_handle_interrupt(iface); + while (1) { + twi_int_status = read_INT_STAT(iface); + if (!twi_int_status) + break; + /* Clear interrupt status */ + write_INT_STAT(iface, twi_int_status); + bfin_twi_handle_interrupt(iface, twi_int_status); + SSYNC(); + } spin_unlock_irqrestore(&iface->lock, flags); return IRQ_HANDLED; } -- 2.20.1