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net: ipa: use state to determine channel command success 

The result of issuing a channel control command should be that the
channel changes state.  If enabled, a completion interrupt signals
that the channel state has changed.  This interrupt is enabled by
gsi_channel_command() and disabled again after the command has
completed (or we time out).

There is a window of time--after the completion interrupt is disabled
but before the channel state is read--during which the command could
complete successfully without interrupting.  This would cause the
channel to transition to the desired new state.

So whether a channel command ends via completion interrupt or
timeout, we can consider the command successful if the channel
has entered the desired state (and a failure if it has not,
regardless of the cause).

Fixes: d6c9e3f506 ("net: ipa: only enable generic command completion IRQ when needed");
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
zero-sugar-mainline-defconfig
Alex Elder 2020-12-22 12:00:11 -06:00 committed by Jakub Kicinski
parent 94ad8f3ac6
commit 6ffddf3b3d
1 changed files with 22 additions and 21 deletions
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43
drivers/net/ipa/gsi.c
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@ -505,15 +505,15 @@ static int gsi_channel_alloc_command(struct gsi *gsi, u32 channel_id)
ret = gsi_channel_command(channel, GSI_CH_ALLOCATE);
/* Channel state will normally have been updated */
/* If successful the channel state will have changed */
state = gsi_channel_state(channel);
if (!ret && state != GSI_CHANNEL_STATE_ALLOCATED) {
dev_err(dev, "channel %u bad state %u after alloc\n",
channel_id, state);
ret = -EIO;
}
if (state == GSI_CHANNEL_STATE_ALLOCATED)
return 0;
return ret;
dev_err(dev, "channel %u bad state %u after alloc\n",
channel_id, state);
return -EIO;
}
/* Start an ALLOCATED channel */
@ -533,15 +533,15 @@ static int gsi_channel_start_command(struct gsi_channel *channel)
ret = gsi_channel_command(channel, GSI_CH_START);
/* Channel state will normally have been updated */
/* If successful the channel state will have changed */
state = gsi_channel_state(channel);
if (!ret && state != GSI_CHANNEL_STATE_STARTED) {
dev_err(dev, "channel %u bad state %u after start\n",
gsi_channel_id(channel), state);
ret = -EIO;
}
if (state == GSI_CHANNEL_STATE_STARTED)
return 0;
return ret;
dev_err(dev, "channel %u bad state %u after start\n",
gsi_channel_id(channel), state);
return -EIO;
}
/* Stop a GSI channel in STARTED state */
@ -568,10 +568,10 @@ static int gsi_channel_stop_command(struct gsi_channel *channel)
ret = gsi_channel_command(channel, GSI_CH_STOP);
/* Channel state will normally have been updated */
/* If successful the channel state will have changed */
state = gsi_channel_state(channel);
if (ret || state == GSI_CHANNEL_STATE_STOPPED)
return ret;
if (state == GSI_CHANNEL_STATE_STOPPED)
return 0;
/* We may have to try again if stop is in progress */
if (state == GSI_CHANNEL_STATE_STOP_IN_PROC)
@ -604,9 +604,9 @@ static void gsi_channel_reset_command(struct gsi_channel *channel)
ret = gsi_channel_command(channel, GSI_CH_RESET);
/* Channel state will normally have been updated */
/* If successful the channel state will have changed */
state = gsi_channel_state(channel);
if (!ret && state != GSI_CHANNEL_STATE_ALLOCATED)
if (state != GSI_CHANNEL_STATE_ALLOCATED)
dev_err(dev, "channel %u bad state %u after reset\n",
gsi_channel_id(channel), state);
}
@ -628,9 +628,10 @@ static void gsi_channel_de_alloc_command(struct gsi *gsi, u32 channel_id)
ret = gsi_channel_command(channel, GSI_CH_DE_ALLOC);
/* Channel state will normally have been updated */
/* If successful the channel state will have changed */
state = gsi_channel_state(channel);
if (!ret && state != GSI_CHANNEL_STATE_NOT_ALLOCATED)
if (state != GSI_CHANNEL_STATE_NOT_ALLOCATED)
dev_err(dev, "channel %u bad state %u after dealloc\n",
channel_id, state);
}