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 <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>

diff --git a/drivers/i2c/busses/i2c-bfin-twi.c b/drivers/i2c/busses/i2c-bfin-twi.c
index 0279a7a6b86c5785b7235082cbf82c69e8bd073c..ff61c4b2209525a36f3ee01ed3462f801dead6d8 100644 (file)
--- 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},
 };
 
        {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) {
        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--;
                }
                        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);
                }
                                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) {
        }
        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);
                } 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)
                } 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);
                        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) {
        }
        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);
                write_INT_MASK(iface, 0);
                write_MASTER_STAT(iface, 0x3e);
                write_MASTER_CTL(iface, 0);

-               SSYNC();

                iface->result = -EIO;
 
                if (mast_stat & LOSTARB)
                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) {
                 * 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.
                        /* 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) {
                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
                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);
                        /* 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++;
                } 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--;
                                        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);
                        /* 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);
                } else {
                        iface->result = 1;
                        write_INT_MASK(iface, 0);
                        write_MASTER_CTL(iface, 0);

-                       SSYNC();

                }
        }
        complete(&iface->complete);
                }
        }
        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;
 {
        struct bfin_twi_iface *iface = dev_id;
        unsigned long flags;

+       unsigned short twi_int_status;

 
        spin_lock_irqsave(&iface->lock, flags);
 
        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;
 }
        spin_unlock_irqrestore(&iface->lock, flags);
        return IRQ_HANDLED;
 }