Commit 6ffddf3b authored by Alex Elder's avatar Alex Elder Committed by Jakub Kicinski
Browse files

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: d6c9e3f5 ("net: ipa: only enable generic command completion IRQ when needed");
Signed-off-by: default avatarAlex Elder <elder@linaro.org>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 94ad8f3a

drivers/net/ipa/gsi.c

+22 −21
Original line number Diff line number Diff line
@@ -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) {

	if (state == GSI_CHANNEL_STATE_ALLOCATED)

		return 0;



	dev_err(dev, "channel %u bad state %u after alloc\n",

		channel_id, state);

		ret = -EIO;

	}



	return ret;

	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) {

	if (state == GSI_CHANNEL_STATE_STARTED)

		return 0;



	dev_err(dev, "channel %u bad state %u after start\n",

		gsi_channel_id(channel), state);

		ret = -EIO;

	}



	return ret;

	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);

}