<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/net/can, branch v3.16.76</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>can: flexcan: fix timeout when set small bitrate</title>
<updated>2019-10-05T15:19:54+00:00</updated>
<author>
<name>Joakim Zhang</name>
<email>qiangqing.zhang@nxp.com</email>
</author>
<published>2019-01-31T09:37:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=58caee4bd1a4dadbf2cde641d9ffd435bb42f864'/>
<id>58caee4bd1a4dadbf2cde641d9ffd435bb42f864</id>
<content type='text'>
commit 247e5356a709eb49a0d95ff2a7f07dac05c8252c upstream.

Current we can meet timeout issue when setting a small bitrate like
10000 as follows on i.MX6UL EVK board (ipg clock = 66MHZ, per clock =
30MHZ):

| root@imx6ul7d:~# ip link set can0 up type can bitrate 10000

A link change request failed with some changes committed already.
Interface can0 may have been left with an inconsistent configuration,
please check.

| RTNETLINK answers: Connection timed out

It is caused by calling of flexcan_chip_unfreeze() timeout.

Originally the code is using usleep_range(10, 20) for unfreeze
operation, but the patch (8badd65 can: flexcan: avoid calling
usleep_range from interrupt context) changed it into udelay(10) which is
only a half delay of before, there're also some other delay changes.

After double to FLEXCAN_TIMEOUT_US to 100 can fix the issue.

Meanwhile, Rasmus Villemoes reported that even with a timeout of 100,
flexcan_probe() fails on the MPC8309, which requires a value of at least
140 to work reliably. 250 works for everyone.

Signed-off-by: Joakim Zhang &lt;qiangqing.zhang@nxp.com&gt;
Reviewed-by: Dong Aisheng &lt;aisheng.dong@nxp.com&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 247e5356a709eb49a0d95ff2a7f07dac05c8252c upstream.

Current we can meet timeout issue when setting a small bitrate like
10000 as follows on i.MX6UL EVK board (ipg clock = 66MHZ, per clock =
30MHZ):

| root@imx6ul7d:~# ip link set can0 up type can bitrate 10000

A link change request failed with some changes committed already.
Interface can0 may have been left with an inconsistent configuration,
please check.

| RTNETLINK answers: Connection timed out

It is caused by calling of flexcan_chip_unfreeze() timeout.

Originally the code is using usleep_range(10, 20) for unfreeze
operation, but the patch (8badd65 can: flexcan: avoid calling
usleep_range from interrupt context) changed it into udelay(10) which is
only a half delay of before, there're also some other delay changes.

After double to FLEXCAN_TIMEOUT_US to 100 can fix the issue.

Meanwhile, Rasmus Villemoes reported that even with a timeout of 100,
flexcan_probe() fails on the MPC8309, which requires a value of at least
140 to work reliably. 250 works for everyone.

Signed-off-by: Joakim Zhang &lt;qiangqing.zhang@nxp.com&gt;
Reviewed-by: Dong Aisheng &lt;aisheng.dong@nxp.com&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>can: dev: __can_get_echo_skb(): fix bogous check for non-existing skb by removing it</title>
<updated>2019-05-02T20:41:27+00:00</updated>
<author>
<name>Manfred Schlaegl</name>
<email>manfred.schlaegl@ginzinger.com</email>
</author>
<published>2018-12-19T18:39:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d34ea495d452540fab2ecee501846177c99c60c2'/>
<id>d34ea495d452540fab2ecee501846177c99c60c2</id>
<content type='text'>
commit 7b12c8189a3dc50638e7d53714c88007268d47ef upstream.

This patch revert commit 7da11ba5c506
("can: dev: __can_get_echo_skb(): print error message, if trying to echo non existing skb")

After introduction of this change we encountered following new error
message on various i.MX plattforms (flexcan):

| flexcan 53fc8000.can can0: __can_get_echo_skb: BUG! Trying to echo non
| existing skb: can_priv::echo_skb[0]

The introduction of the message was a mistake because
priv-&gt;echo_skb[idx] = NULL is a perfectly valid in following case: If
CAN_RAW_LOOPBACK is disabled (setsockopt) in applications, the pkt_type
of the tx skb's given to can_put_echo_skb is set to PACKET_LOOPBACK. In
this case can_put_echo_skb will not set priv-&gt;echo_skb[idx]. It is
therefore kept NULL.

As additional argument for revert: The order of check and usage of idx
was changed. idx is used to access an array element before checking it's
boundaries.

Signed-off-by: Manfred Schlaegl &lt;manfred.schlaegl@ginzinger.com&gt;
Fixes: 7da11ba5c506 ("can: dev: __can_get_echo_skb(): print error message, if trying to echo non existing skb")
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 7b12c8189a3dc50638e7d53714c88007268d47ef upstream.

This patch revert commit 7da11ba5c506
("can: dev: __can_get_echo_skb(): print error message, if trying to echo non existing skb")

After introduction of this change we encountered following new error
message on various i.MX plattforms (flexcan):

| flexcan 53fc8000.can can0: __can_get_echo_skb: BUG! Trying to echo non
| existing skb: can_priv::echo_skb[0]

The introduction of the message was a mistake because
priv-&gt;echo_skb[idx] = NULL is a perfectly valid in following case: If
CAN_RAW_LOOPBACK is disabled (setsockopt) in applications, the pkt_type
of the tx skb's given to can_put_echo_skb is set to PACKET_LOOPBACK. In
this case can_put_echo_skb will not set priv-&gt;echo_skb[idx]. It is
therefore kept NULL.

As additional argument for revert: The order of check and usage of idx
was changed. idx is used to access an array element before checking it's
boundaries.

Signed-off-by: Manfred Schlaegl &lt;manfred.schlaegl@ginzinger.com&gt;
Fixes: 7da11ba5c506 ("can: dev: __can_get_echo_skb(): print error message, if trying to echo non existing skb")
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>can: dev: __can_get_echo_skb(): print error message, if trying to echo non existing skb</title>
<updated>2019-02-11T17:53:57+00:00</updated>
<author>
<name>Marc Kleine-Budde</name>
<email>mkl@pengutronix.de</email>
</author>
<published>2018-10-31T13:15:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=bf0faabcabde964e3d11146e23022b79976da0a6'/>
<id>bf0faabcabde964e3d11146e23022b79976da0a6</id>
<content type='text'>
commit 7da11ba5c5066dadc2e96835a6233d56d7b7764a upstream.

Prior to echoing a successfully transmitted CAN frame (by calling
can_get_echo_skb()), CAN drivers have to put the CAN frame (by calling
can_put_echo_skb() in the transmit function). These put and get function
take an index as parameter, which is used to identify the CAN frame.

A driver calling can_get_echo_skb() with a index not pointing to a skb
is a BUG, so add an appropriate error message.

Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 7da11ba5c5066dadc2e96835a6233d56d7b7764a upstream.

Prior to echoing a successfully transmitted CAN frame (by calling
can_get_echo_skb()), CAN drivers have to put the CAN frame (by calling
can_put_echo_skb() in the transmit function). These put and get function
take an index as parameter, which is used to identify the CAN frame.

A driver calling can_get_echo_skb() with a index not pointing to a skb
is a BUG, so add an appropriate error message.

Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>can: dev: __can_get_echo_skb(): Don't crash the kernel if can_priv::echo_skb is accessed out of bounds</title>
<updated>2019-02-11T17:53:57+00:00</updated>
<author>
<name>Marc Kleine-Budde</name>
<email>mkl@pengutronix.de</email>
</author>
<published>2018-10-31T13:05:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=0617eab85a2fae992822f78612ac7edc1c0ea336'/>
<id>0617eab85a2fae992822f78612ac7edc1c0ea336</id>
<content type='text'>
commit e7a6994d043a1e31d5b17706a22ce33d2a3e4cdc upstream.

If the "struct can_priv::echo_skb" is accessed out of bounds would lead
to a kernel crash. Better print a sensible warning message instead and
try to recover.

Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit e7a6994d043a1e31d5b17706a22ce33d2a3e4cdc upstream.

If the "struct can_priv::echo_skb" is accessed out of bounds would lead
to a kernel crash. Better print a sensible warning message instead and
try to recover.

Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>can: dev: __can_get_echo_skb(): replace struct can_frame by canfd_frame to access frame length</title>
<updated>2019-02-11T17:53:57+00:00</updated>
<author>
<name>Marc Kleine-Budde</name>
<email>mkl@pengutronix.de</email>
</author>
<published>2018-10-31T10:08:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=66959c01a179837d34d0b490caa7fe180fd69ad3'/>
<id>66959c01a179837d34d0b490caa7fe180fd69ad3</id>
<content type='text'>
commit 200f5c49f7a2cd694436bfc6cb0662b794c96736 upstream.

This patch replaces the use of "struct can_frame::can_dlc" by "struct
canfd_frame::len" to access the frame's length. As it is ensured that
both structures have a compatible memory layout for this member this is
no functional change. Futher, this compatibility is documented in a
comment.

Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 200f5c49f7a2cd694436bfc6cb0662b794c96736 upstream.

This patch replaces the use of "struct can_frame::can_dlc" by "struct
canfd_frame::len" to access the frame's length. As it is ensured that
both structures have a compatible memory layout for this member this is
no functional change. Futher, this compatibility is documented in a
comment.

Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>can: dev: can_get_echo_skb(): factor out non sending code to __can_get_echo_skb()</title>
<updated>2019-02-11T17:53:57+00:00</updated>
<author>
<name>Marc Kleine-Budde</name>
<email>mkl@pengutronix.de</email>
</author>
<published>2018-10-31T09:37:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1563d207e3202f5d685d559934dd20ccb8df51b3'/>
<id>1563d207e3202f5d685d559934dd20ccb8df51b3</id>
<content type='text'>
commit a4310fa2f24687888ce80fdb0e88583561a23700 upstream.

This patch factors out all non sending parts of can_get_echo_skb() into
a seperate function __can_get_echo_skb(), so that it can be re-used in
an upcoming patch.

Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit a4310fa2f24687888ce80fdb0e88583561a23700 upstream.

This patch factors out all non sending parts of can_get_echo_skb() into
a seperate function __can_get_echo_skb(), so that it can be re-used in
an upcoming patch.

Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>can: ems_usb: Fix memory leak on ems_usb_disconnect()</title>
<updated>2018-11-20T18:05:52+00:00</updated>
<author>
<name>Anton Vasilyev</name>
<email>vasilyev@ispras.ru</email>
</author>
<published>2018-07-27T15:50:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=0df8731c9960e20531470e101dca0c646497eba3'/>
<id>0df8731c9960e20531470e101dca0c646497eba3</id>
<content type='text'>
commit 72c05f32f4a5055c9c8fe889bb6903ec959c0aad upstream.

ems_usb_probe() allocates memory for dev-&gt;tx_msg_buffer, but there
is no its deallocation in ems_usb_disconnect().

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Anton Vasilyev &lt;vasilyev@ispras.ru&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 72c05f32f4a5055c9c8fe889bb6903ec959c0aad upstream.

ems_usb_probe() allocates memory for dev-&gt;tx_msg_buffer, but there
is no its deallocation in ems_usb_disconnect().

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Anton Vasilyev &lt;vasilyev@ispras.ru&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>can: xilinx_can: fix incorrect clear of non-processed interrupts</title>
<updated>2018-11-20T18:05:48+00:00</updated>
<author>
<name>Anssi Hannula</name>
<email>anssi.hannula@bitwise.fi</email>
</author>
<published>2018-02-26T12:39:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f5437a2262a164b5fab4de29f3d38c15cd1ebad3'/>
<id>f5437a2262a164b5fab4de29f3d38c15cd1ebad3</id>
<content type='text'>
commit 2f4f0f338cf453bfcdbcf089e177c16f35f023c8 upstream.

xcan_interrupt() clears ERROR|RXOFLV|BSOFF|ARBLST interrupts if any of
them is asserted. This does not take into account that some of them
could have been asserted between interrupt status read and interrupt
clear, therefore clearing them without handling them.

Fix the code to only clear those interrupts that it knows are asserted
and therefore going to be processed in xcan_err_interrupt().

Fixes: b1201e44f50b ("can: xilinx CAN controller support")
Signed-off-by: Anssi Hannula &lt;anssi.hannula@bitwise.fi&gt;
Cc: Michal Simek &lt;michal.simek@xilinx.com&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 2f4f0f338cf453bfcdbcf089e177c16f35f023c8 upstream.

xcan_interrupt() clears ERROR|RXOFLV|BSOFF|ARBLST interrupts if any of
them is asserted. This does not take into account that some of them
could have been asserted between interrupt status read and interrupt
clear, therefore clearing them without handling them.

Fix the code to only clear those interrupts that it knows are asserted
and therefore going to be processed in xcan_err_interrupt().

Fixes: b1201e44f50b ("can: xilinx CAN controller support")
Signed-off-by: Anssi Hannula &lt;anssi.hannula@bitwise.fi&gt;
Cc: Michal Simek &lt;michal.simek@xilinx.com&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>can: xilinx_can: fix RX overflow interrupt not being enabled</title>
<updated>2018-11-20T18:05:48+00:00</updated>
<author>
<name>Anssi Hannula</name>
<email>anssi.hannula@bitwise.fi</email>
</author>
<published>2018-02-26T12:27:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f51771e322b96dd8fdcdfcc9314e7cd2f9eebf94'/>
<id>f51771e322b96dd8fdcdfcc9314e7cd2f9eebf94</id>
<content type='text'>
commit 83997997252f5d3fc7f04abc24a89600c2b504ab upstream.

RX overflow interrupt (RXOFLW) is disabled even though xcan_interrupt()
processes it. This means that an RX overflow interrupt will only be
processed when another interrupt gets asserted (e.g. for RX/TX).

Fix that by enabling the RXOFLW interrupt.

Fixes: b1201e44f50b ("can: xilinx CAN controller support")
Signed-off-by: Anssi Hannula &lt;anssi.hannula@bitwise.fi&gt;
Cc: Michal Simek &lt;michal.simek@xilinx.com&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 83997997252f5d3fc7f04abc24a89600c2b504ab upstream.

RX overflow interrupt (RXOFLW) is disabled even though xcan_interrupt()
processes it. This means that an RX overflow interrupt will only be
processed when another interrupt gets asserted (e.g. for RX/TX).

Fix that by enabling the RXOFLW interrupt.

Fixes: b1201e44f50b ("can: xilinx CAN controller support")
Signed-off-by: Anssi Hannula &lt;anssi.hannula@bitwise.fi&gt;
Cc: Michal Simek &lt;michal.simek@xilinx.com&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>can: xilinx_can: keep only 1-2 frames in TX FIFO to fix TX accounting</title>
<updated>2018-11-20T18:05:48+00:00</updated>
<author>
<name>Anssi Hannula</name>
<email>anssi.hannula@bitwise.fi</email>
</author>
<published>2017-02-23T12:50:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=5a2565c48ca547b373d7574069fc5ed5c9bbf8b4'/>
<id>5a2565c48ca547b373d7574069fc5ed5c9bbf8b4</id>
<content type='text'>
commit 620050d9c2be15c47017ba95efe59e0832e99a56 upstream.

The xilinx_can driver assumes that the TXOK interrupt only clears after
it has been acknowledged as many times as there have been successfully
sent frames.

However, the documentation does not mention such behavior, instead
saying just that the interrupt is cleared when the clear bit is set.

Similarly, testing seems to also suggest that it is immediately cleared
regardless of the amount of frames having been sent. Performing some
heavy TX load and then going back to idle has the tx_head drifting
further away from tx_tail over time, steadily reducing the amount of
frames the driver keeps in the TX FIFO (but not to zero, as the TXOK
interrupt always frees up space for 1 frame from the driver's
perspective, so frames continue to be sent) and delaying the local echo
frames.

The TX FIFO tracking is also otherwise buggy as it does not account for
TX FIFO being cleared after software resets, causing
  BUG!, TX FIFO full when queue awake!
messages to be output.

There does not seem to be any way to accurately track the state of the
TX FIFO for local echo support while using the full TX FIFO.

The Zynq version of the HW (but not the soft-AXI version) has watermark
programming support and with it an additional TX-FIFO-empty interrupt
bit.

Modify the driver to only put 1 frame into TX FIFO at a time on soft-AXI
and 2 frames at a time on Zynq. On Zynq the TXFEMP interrupt bit is used
to detect whether 1 or 2 frames have been sent at interrupt processing
time.

Tested with the integrated CAN on Zynq-7000 SoC. The 1-frame-FIFO mode
was also tested.

An alternative way to solve this would be to drop local echo support but
keep using the full TX FIFO.

v2: Add FIFO space check before TX queue wake with locking to
synchronize with queue stop. This avoids waking the queue when xmit()
had just filled it.

v3: Keep local echo support and reduce the amount of frames in FIFO
instead as suggested by Marc Kleine-Budde.

Fixes: b1201e44f50b ("can: xilinx CAN controller support")
Signed-off-by: Anssi Hannula &lt;anssi.hannula@bitwise.fi&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 620050d9c2be15c47017ba95efe59e0832e99a56 upstream.

The xilinx_can driver assumes that the TXOK interrupt only clears after
it has been acknowledged as many times as there have been successfully
sent frames.

However, the documentation does not mention such behavior, instead
saying just that the interrupt is cleared when the clear bit is set.

Similarly, testing seems to also suggest that it is immediately cleared
regardless of the amount of frames having been sent. Performing some
heavy TX load and then going back to idle has the tx_head drifting
further away from tx_tail over time, steadily reducing the amount of
frames the driver keeps in the TX FIFO (but not to zero, as the TXOK
interrupt always frees up space for 1 frame from the driver's
perspective, so frames continue to be sent) and delaying the local echo
frames.

The TX FIFO tracking is also otherwise buggy as it does not account for
TX FIFO being cleared after software resets, causing
  BUG!, TX FIFO full when queue awake!
messages to be output.

There does not seem to be any way to accurately track the state of the
TX FIFO for local echo support while using the full TX FIFO.

The Zynq version of the HW (but not the soft-AXI version) has watermark
programming support and with it an additional TX-FIFO-empty interrupt
bit.

Modify the driver to only put 1 frame into TX FIFO at a time on soft-AXI
and 2 frames at a time on Zynq. On Zynq the TXFEMP interrupt bit is used
to detect whether 1 or 2 frames have been sent at interrupt processing
time.

Tested with the integrated CAN on Zynq-7000 SoC. The 1-frame-FIFO mode
was also tested.

An alternative way to solve this would be to drop local echo support but
keep using the full TX FIFO.

v2: Add FIFO space check before TX queue wake with locking to
synchronize with queue stop. This avoids waking the queue when xmit()
had just filled it.

v3: Keep local echo support and reduce the amount of frames in FIFO
instead as suggested by Marc Kleine-Budde.

Fixes: b1201e44f50b ("can: xilinx CAN controller support")
Signed-off-by: Anssi Hannula &lt;anssi.hannula@bitwise.fi&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
</feed>
