Commit a2003b30 authored by Alex Elder's avatar Alex Elder Committed by David S. Miller
Browse files

net: ipa: do not cache channel state 



It is possible for a GSI channel's state to be changed as a result
of an action by a different execution environment.  Specifically,
the modem is able to issue a GSI generic command that causes a state
change on a GSI channel associated with the AP.

A channel's state only needs to be known when a channel is allocated
or deallocaed, started or stopped, or reset.  So there is little
value in caching the state anyway.

Stop recording a copy of the channel's last known state, and instead
fetch the true state from hardware whenever it's needed.  In such
cases, *do* record the state in a local variable, in case an error
message reports it (so the value reported is the value seen).

Signed-off-by: default avatarAlex Elder <elder@linaro.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent aba7924f

drivers/net/ipa/gsi.c

+54 −33
Original line number Diff line number Diff line
@@ -415,7 +415,7 @@ static void gsi_evt_ring_de_alloc_command(struct gsi *gsi, u32 evt_ring_id) 
			evt_ring->state);

}



/* Return the hardware's notion of the current state of a channel */

/* Fetch the current state of a channel from hardware */

static enum gsi_channel_state gsi_channel_state(struct gsi_channel *channel)

{

	u32 channel_id = gsi_channel_id(channel);
@@ -433,16 +433,18 @@ gsi_channel_command(struct gsi_channel *channel, enum gsi_ch_cmd_opcode opcode) 
{

	struct completion *completion = &channel->completion;

	u32 channel_id = gsi_channel_id(channel);

	struct gsi *gsi = channel->gsi;

	u32 val;



	val = u32_encode_bits(channel_id, CH_CHID_FMASK);

	val |= u32_encode_bits(opcode, CH_OPCODE_FMASK);



	if (gsi_command(channel->gsi, GSI_CH_CMD_OFFSET, val, completion))

	if (gsi_command(gsi, GSI_CH_CMD_OFFSET, val, completion))

		return 0;	/* Success! */



	dev_err(channel->gsi->dev, "GSI command %u to channel %u timed out "

		"(state is %u)\n", opcode, channel_id, channel->state);

	dev_err(gsi->dev,

		"GSI command %u to channel %u timed out (state is %u)\n",

		opcode, channel_id, gsi_channel_state(channel));



	return -ETIMEDOUT;

}
@@ -451,18 +453,21 @@ gsi_channel_command(struct gsi_channel *channel, enum gsi_ch_cmd_opcode opcode) 
static int gsi_channel_alloc_command(struct gsi *gsi, u32 channel_id)

{

	struct gsi_channel *channel = &gsi->channel[channel_id];

	enum gsi_channel_state state;

	int ret;



	/* Get initial channel state */

	channel->state = gsi_channel_state(channel);



	if (channel->state != GSI_CHANNEL_STATE_NOT_ALLOCATED)

	state = gsi_channel_state(channel);

	if (state != GSI_CHANNEL_STATE_NOT_ALLOCATED)

		return -EINVAL;



	ret = gsi_channel_command(channel, GSI_CH_ALLOCATE);

	if (!ret && channel->state != GSI_CHANNEL_STATE_ALLOCATED) {



	/* Channel state will normally have been updated */

	state = gsi_channel_state(channel);

	if (!ret && state != GSI_CHANNEL_STATE_ALLOCATED) {

		dev_err(gsi->dev, "bad channel state (%u) after alloc\n",

			channel->state);

			state);

		ret = -EIO;

	}
@@ -472,18 +477,21 @@ static int gsi_channel_alloc_command(struct gsi *gsi, u32 channel_id) 
/* Start an ALLOCATED channel */

static int gsi_channel_start_command(struct gsi_channel *channel)

{

	enum gsi_channel_state state = channel->state;

	enum gsi_channel_state state;

	int ret;



	state = gsi_channel_state(channel);

	if (state != GSI_CHANNEL_STATE_ALLOCATED &&

	    state != GSI_CHANNEL_STATE_STOPPED)

		return -EINVAL;



	ret = gsi_channel_command(channel, GSI_CH_START);

	if (!ret && channel->state != GSI_CHANNEL_STATE_STARTED) {



	/* Channel state will normally have been updated */

	state = gsi_channel_state(channel);

	if (!ret && state != GSI_CHANNEL_STATE_STARTED) {

		dev_err(channel->gsi->dev,

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

			channel->state);

			"bad channel state (%u) after start\n", state);

		ret = -EIO;

	}
@@ -493,23 +501,27 @@ static int gsi_channel_start_command(struct gsi_channel *channel) 
/* Stop a GSI channel in STARTED state */

static int gsi_channel_stop_command(struct gsi_channel *channel)

{

	enum gsi_channel_state state = channel->state;

	enum gsi_channel_state state;

	int ret;



	state = gsi_channel_state(channel);

	if (state != GSI_CHANNEL_STATE_STARTED &&

	    state != GSI_CHANNEL_STATE_STOP_IN_PROC)

		return -EINVAL;



	ret = gsi_channel_command(channel, GSI_CH_STOP);

	if (ret || channel->state == GSI_CHANNEL_STATE_STOPPED)



	/* Channel state will normally have been updated */

	state = gsi_channel_state(channel);

	if (ret || state == GSI_CHANNEL_STATE_STOPPED)

		return ret;



	/* We may have to try again if stop is in progress */

	if (channel->state == GSI_CHANNEL_STATE_STOP_IN_PROC)

	if (state == GSI_CHANNEL_STATE_STOP_IN_PROC)

		return -EAGAIN;



	dev_err(channel->gsi->dev, "bad channel state (%u) after stop\n",

		channel->state);

	dev_err(channel->gsi->dev,

		"bad channel state (%u) after stop\n", state);



	return -EIO;

}
@@ -517,41 +529,49 @@ static int gsi_channel_stop_command(struct gsi_channel *channel) 
/* Reset a GSI channel in ALLOCATED or ERROR state. */

static void gsi_channel_reset_command(struct gsi_channel *channel)

{

	enum gsi_channel_state state;

	int ret;



	msleep(1);	/* A short delay is required before a RESET command */



	if (channel->state != GSI_CHANNEL_STATE_STOPPED &&

	    channel->state != GSI_CHANNEL_STATE_ERROR) {

	state = gsi_channel_state(channel);

	if (state != GSI_CHANNEL_STATE_STOPPED &&

	    state != GSI_CHANNEL_STATE_ERROR) {

		dev_err(channel->gsi->dev,

			"bad channel state (%u) before reset\n",

			channel->state);

			"bad channel state (%u) before reset\n", state);

		return;

	}



	ret = gsi_channel_command(channel, GSI_CH_RESET);

	if (!ret && channel->state != GSI_CHANNEL_STATE_ALLOCATED)



	/* Channel state will normally have been updated */

	state = gsi_channel_state(channel);

	if (!ret && state != GSI_CHANNEL_STATE_ALLOCATED)

		dev_err(channel->gsi->dev,

			"bad channel state (%u) after reset\n",

			channel->state);

			"bad channel state (%u) after reset\n", state);

}



/* Deallocate an ALLOCATED GSI channel */

static void gsi_channel_de_alloc_command(struct gsi *gsi, u32 channel_id)

{

	struct gsi_channel *channel = &gsi->channel[channel_id];

	enum gsi_channel_state state;

	int ret;



	if (channel->state != GSI_CHANNEL_STATE_ALLOCATED) {

		dev_err(gsi->dev, "bad channel state (%u) before dealloc\n",

			channel->state);

	state = gsi_channel_state(channel);

	if (state != GSI_CHANNEL_STATE_ALLOCATED) {

		dev_err(gsi->dev,

			"bad channel state (%u) before dealloc\n", state);

		return;

	}



	ret = gsi_channel_command(channel, GSI_CH_DE_ALLOC);

	if (!ret && channel->state != GSI_CHANNEL_STATE_NOT_ALLOCATED)

		dev_err(gsi->dev, "bad channel state (%u) after dealloc\n",

			channel->state);



	/* Channel state will normally have been updated */

	state = gsi_channel_state(channel);

	if (!ret && state != GSI_CHANNEL_STATE_NOT_ALLOCATED)

		dev_err(gsi->dev,

			"bad channel state (%u) after dealloc\n", state);

}



/* Ring an event ring doorbell, reporting the last entry processed by the AP.
@@ -778,6 +798,7 @@ int gsi_channel_start(struct gsi *gsi, u32 channel_id) 
int gsi_channel_stop(struct gsi *gsi, u32 channel_id)

{

	struct gsi_channel *channel = &gsi->channel[channel_id];

	enum gsi_channel_state state;

	u32 retries;

	int ret;
@@ -787,7 +808,8 @@ int gsi_channel_stop(struct gsi *gsi, u32 channel_id) 
	 * STOP command timed out.  We won't stop a channel if stopping it

	 * was successful previously (so we still want the freeze above).

	 */

	if (channel->state == GSI_CHANNEL_STATE_STOPPED)

	state = gsi_channel_state(channel);

	if (state == GSI_CHANNEL_STATE_STOPPED)

		return 0;



	/* RX channels might require a little time to enter STOPPED state */
@@ -941,7 +963,6 @@ static void gsi_isr_chan_ctrl(struct gsi *gsi) 
		channel_mask ^= BIT(channel_id);



		channel = &gsi->channel[channel_id];

		channel->state = gsi_channel_state(channel);



		complete(&channel->completion);

	}

drivers/net/ipa/gsi.h

+1 −2
Original line number Diff line number Diff line
@@ -113,8 +113,7 @@ struct gsi_channel { 
	u16 tre_count;

	u16 event_count;



	struct completion completion;	/* signals channel state changes */

	enum gsi_channel_state state;

	struct completion completion;	/* signals channel command completion */



	struct gsi_ring tre_ring;

	u32 evt_ring_id;

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