[PATCH net-next 2/2] net: ipa: do not cache channel state
From: Alex Elder
Date: Thu Apr 30 2020 - 18:13:40 EST
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: Alex Elder <elder@xxxxxxxxxx>
---
drivers/net/ipa/gsi.c | 87 +++++++++++++++++++++++++++----------------
drivers/net/ipa/gsi.h | 3 +-
2 files changed, 55 insertions(+), 35 deletions(-)
diff --git a/drivers/net/ipa/gsi.c b/drivers/net/ipa/gsi.c
index 6946c39b664a..8184d34124b7 100644
--- a/drivers/net/ipa/gsi.c
+++ b/drivers/net/ipa/gsi.c
@@ -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);
}
diff --git a/drivers/net/ipa/gsi.h b/drivers/net/ipa/gsi.h
index 0698ff1ae7a6..19471017fadf 100644
--- a/drivers/net/ipa/gsi.h
+++ b/drivers/net/ipa/gsi.h
@@ -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;
--
2.20.1