Commit 12bd93c1 authored by Corey Minyard's avatar Corey Minyard Committed by Paolo Bonzini
Browse files

i2c: pm_smbus: Don't delay host status register busy bit when interrupts are enabled 



Change 880b1ffe "smbus: do not immediately complete commands"
changed pm_smbus to delay setting the host busy bit until the status
register was read, to work around a bug in AMIBIOS.  Unfortunately,
when interrupts are enabled, the status register will never get read
and the processing will never happen.

Modify the code to only delay setting the host busy bit if interrupts
are not enabled.

Signed-off-by: default avatarCorey Minyard <cminyard@mvista.com>
Cc: Hervé Poussineau <hpoussin@reactos.org>
Cc: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <1534796770-10295-8-git-send-email-minyard@acm.org>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent e724385a

hw/i2c/pm_smbus.c

+13 −6
Original line number Diff line number Diff line
@@ -80,9 +80,6 @@ static void smb_transaction(PMSMBus *s) 
    I2CBus *bus = s->smbus;

    int ret;



    assert(s->smb_stat & STS_HOST_BUSY);

    s->smb_stat &= ~STS_HOST_BUSY;



    SMBUS_DPRINTF("SMBus trans addr=0x%02x prot=0x%02x\n", addr, prot);

    /* Transaction isn't exec if STS_DEV_ERR bit set */

    if ((s->smb_stat & STS_DEV_ERR) != 0)  {
@@ -209,10 +206,19 @@ error: 


static void smb_transaction_start(PMSMBus *s)

{

    if (s->smb_ctl & CTL_INTREN) {

        smb_transaction(s);

    } else {

        /* Do not execute immediately the command; it will be

     * executed when guest will read SMB_STAT register */

         * executed when guest will read SMB_STAT register.  This

         * is to work around a bug in AMIBIOS (that is working

         * around another bug in some specific hardware) where

         * it waits for STS_HOST_BUSY to be set before waiting

         * checking for status.  If STS_HOST_BUSY doesn't get

         * set, it gets stuck. */

        s->smb_stat |= STS_HOST_BUSY;

    }

}



static bool

smb_irq_value(PMSMBus *s)
@@ -330,6 +336,7 @@ static uint64_t smb_ioport_readb(void *opaque, hwaddr addr, unsigned width) 
        val = s->smb_stat;

        if (s->smb_stat & STS_HOST_BUSY) {

            /* execute command now */

            s->smb_stat &= ~STS_HOST_BUSY;

            smb_transaction(s);

        }

        break;