Re: [PATCH] i2c: imx: add slave support. v2 status

2016-12-01 Thread Frkuska, Joshua 

Hello Maxim,

I have a few questions for you. Please see my comments inline below.

In addition, I have modified your patch-set slightly and I would like to 
progress it to merger if you do not have any issues with this. I would 
like to sync with you here before moving forward and submitting a new patch.


Thank you and best regards,

Joshua

On 11/01/2016 03:21 AM, Maxim Syrchin wrote:

Hello,

Please find some comments below.


31.10.2016 5:14, Frkuska, Joshua пишет:

Hello Maxim,

Thank you very much for the intermediate patch. I am in the process 
of reviewing it. Please let me clarify a few questions I have.


1. What alternative to "bus busy/bus free/IBB" polling do you have in 
mind? This seems like a reasonable approach to me.
We didn't find any suitable alternatives. The only one we're 
considered was using timeout on receive (which is kind of polling of 
course)

2. What are the major points you consider in need of refactoring?

As you can see we have implemented FSM in slave thread.
- Due to lack of time all master functionality had not been included 
in State Machine.
Currently there seems to not be a problem of entirely handling master 
functionality in the slave state machine as it is handled outside of it. 
Do you feel everything should be handled in the slave state machine? I 
dont see any holes in the logic currently.
- wait_event_timeout() calls are used in every event handler (obviosly 
it is better to have only one wait function)
It is possible to have a single wait_event_timeout call at the expense 
of a bit of conditional logic in i2c_imx_slave_threadfn but this brings 
me to my next comment

- Need to review state switching code
I have reviewed all states in a state transition table and all of them 
seem well defined. My only question here is in regards to the STATE_SP 
state. I would like to understand your motivation for it. To me it seems 
like this can also be handled in STATE_IDLE but I would like to get your 
reasoning behind it
3. You mention race conditions being fixed in this version relating 
to bus-locking by the slave and breaking slave transactions by the 
master. Does this mean mixed slave/master mode works to your 
satisfaction? If not, what work still needs to be done here?
Yes mixed slave/master mode works ok. It had passed long-lasting 
stress tests (async message exchange of two imx6 boards connected 
together by i2c bus )
4. You mention the need for a slave locking test and a work-around 
(checking IMX_I2C_I2DR and IBB) being in-place. Why is this 
work-around not sufficient?
By the time we discovered I2DR workaround we went far from version 2 
of driver and it wasn't tested. I'm sure that I2DR workaround will 
improve stability, but I do not know if it will fix all issues (i.e. 
passing of stress tests )



Best Regards,
Maxim Syrchin

Thanks again,

Joshua


On 10/28/2016 04:38 AM, Maxim Syrchin wrote:

Hi,
Sorry for huge delay in answering. Unfortunately we don't have 
enough resources now to prepare clean enough patch to be accepted by 
community.
Please find the latest version attached.  Driver has passed stress 
tests, but looks like it need seriuos refactoring (it is 
unnecessarily complicated).
We still have polling in slave code. Since imx doesn't generate 
interrupt on "bus busy"/"bus free" events we have to test IBB bit in 
polling loop.
Comparing to v2 version several race conditions were fixed (bus 
locking by slave, breaking slave transaction by starting master 
xfer). v2 is working pretty good in slave-only or master-only mode. 
It is reasonable to add  slave locking test - sometimes imx6 hw 
doesn't release data line. As workaround we use dummy reading of 
IMX_I2C_I2DR if driver is in  slave mode and IBB bit is set for a 
long time.


Thanks,
Maxim Syrchin


27.10.2016 10:31, Frkuska, Joshua пишет:

Hi Maxim, Dmitriy, Wolfram,

If there is no immediate plan for a third release of the below 
patch set, would it be possible to continue with merging v2 after 
addressing the remaining concerns?



Thank you and regards,

Joshua

Hi Maxim,

On 2016-03-04 11:06:10 in the thread "Re: [PATCH] i2c: imx: add 
slave support. v2"

referenced here: https://patchwork.ozlabs.org/patch/573353/ you said:

Hi Wolfram,
I'm now working on creating new driver version. I think I'll be 
able to

sent it soon.
Do you still plan to release a driver update for an i2c imx driver 
slave support?


Best regards,
Jim Baxter

Re: [PATCH] i2c: imx: add slave support. v2 status

2016-12-01 Thread Frkuska, Joshua 

Hello Maxim,

I have a few questions for you. Please see my comments inline below.

In addition, I have modified your patch-set slightly and I would like to 
progress it to merger if you do not have any issues with this. I would 
like to sync with you here before moving forward and submitting a new patch.


Thank you and best regards,

Joshua

On 11/01/2016 03:21 AM, Maxim Syrchin wrote:

Hello,

Please find some comments below.


31.10.2016 5:14, Frkuska, Joshua пишет:

Hello Maxim,

Thank you very much for the intermediate patch. I am in the process 
of reviewing it. Please let me clarify a few questions I have.


1. What alternative to "bus busy/bus free/IBB" polling do you have in 
mind? This seems like a reasonable approach to me.
We didn't find any suitable alternatives. The only one we're 
considered was using timeout on receive (which is kind of polling of 
course)

2. What are the major points you consider in need of refactoring?

As you can see we have implemented FSM in slave thread.
- Due to lack of time all master functionality had not been included 
in State Machine.
Currently there seems to not be a problem of entirely handling master 
functionality in the slave state machine as it is handled outside of it. 
Do you feel everything should be handled in the slave state machine? I 
dont see any holes in the logic currently.
- wait_event_timeout() calls are used in every event handler (obviosly 
it is better to have only one wait function)
It is possible to have a single wait_event_timeout call at the expense 
of a bit of conditional logic in i2c_imx_slave_threadfn but this brings 
me to my next comment

- Need to review state switching code
I have reviewed all states in a state transition table and all of them 
seem well defined. My only question here is in regards to the STATE_SP 
state. I would like to understand your motivation for it. To me it seems 
like this can also be handled in STATE_IDLE but I would like to get your 
reasoning behind it
3. You mention race conditions being fixed in this version relating 
to bus-locking by the slave and breaking slave transactions by the 
master. Does this mean mixed slave/master mode works to your 
satisfaction? If not, what work still needs to be done here?
Yes mixed slave/master mode works ok. It had passed long-lasting 
stress tests (async message exchange of two imx6 boards connected 
together by i2c bus )
4. You mention the need for a slave locking test and a work-around 
(checking IMX_I2C_I2DR and IBB) being in-place. Why is this 
work-around not sufficient?
By the time we discovered I2DR workaround we went far from version 2 
of driver and it wasn't tested. I'm sure that I2DR workaround will 
improve stability, but I do not know if it will fix all issues (i.e. 
passing of stress tests )



Best Regards,
Maxim Syrchin

Thanks again,

Joshua


On 10/28/2016 04:38 AM, Maxim Syrchin wrote:

Hi,
Sorry for huge delay in answering. Unfortunately we don't have 
enough resources now to prepare clean enough patch to be accepted by 
community.
Please find the latest version attached.  Driver has passed stress 
tests, but looks like it need seriuos refactoring (it is 
unnecessarily complicated).
We still have polling in slave code. Since imx doesn't generate 
interrupt on "bus busy"/"bus free" events we have to test IBB bit in 
polling loop.
Comparing to v2 version several race conditions were fixed (bus 
locking by slave, breaking slave transaction by starting master 
xfer). v2 is working pretty good in slave-only or master-only mode. 
It is reasonable to add  slave locking test - sometimes imx6 hw 
doesn't release data line. As workaround we use dummy reading of 
IMX_I2C_I2DR if driver is in  slave mode and IBB bit is set for a 
long time.


Thanks,
Maxim Syrchin


27.10.2016 10:31, Frkuska, Joshua пишет:

Hi Maxim, Dmitriy, Wolfram,

If there is no immediate plan for a third release of the below 
patch set, would it be possible to continue with merging v2 after 
addressing the remaining concerns?



Thank you and regards,

Joshua

Hi Maxim,

On 2016-03-04 11:06:10 in the thread "Re: [PATCH] i2c: imx: add 
slave support. v2"

referenced here: https://patchwork.ozlabs.org/patch/573353/ you said:

Hi Wolfram,
I'm now working on creating new driver version. I think I'll be 
able to

sent it soon.
Do you still plan to release a driver update for an i2c imx driver 
slave support?


Best regards,
Jim Baxter

Re: [PATCH] i2c: imx: add slave support. v2 status

2016-10-31 Thread Maxim Syrchin 

Hello,

Please find some comments below.


31.10.2016 5:14, Frkuska, Joshua пишет:

Hello Maxim,

Thank you very much for the intermediate patch. I am in the process of 
reviewing it. Please let me clarify a few questions I have.


1. What alternative to "bus busy/bus free/IBB" polling do you have in 
mind? This seems like a reasonable approach to me.
We didn't find any suitable alternatives. The only one we're considered 
was using timeout on receive (which is kind of polling of course)

2. What are the major points you consider in need of refactoring?

As you can see we have implemented FSM in slave thread.
- Due to lack of time all master functionality had not been included in 
State Machine.
- wait_event_timeout() calls are used in every event handler (obviosly 
it is better to have only one wait function)

- Need to review state switching code
3. You mention race conditions being fixed in this version relating to 
bus-locking by the slave and breaking slave transactions by the 
master. Does this mean mixed slave/master mode works to your 
satisfaction? If not, what work still needs to be done here?
Yes mixed slave/master mode works ok. It had passed long-lasting stress 
tests (async message exchange of two imx6 boards connected together by 
i2c bus )
4. You mention the need for a slave locking test and a work-around 
(checking IMX_I2C_I2DR and IBB) being in-place. Why is this 
work-around not sufficient?
By the time we discovered I2DR workaround we went far from version 2 of 
driver and it wasn't tested. I'm sure that I2DR workaround will improve 
stability, but I do not know if it will fix all issues (i.e. passing of 
stress tests )



Best Regards,
Maxim Syrchin

Thanks again,

Joshua


On 10/28/2016 04:38 AM, Maxim Syrchin wrote:

Hi,
Sorry for huge delay in answering. Unfortunately we don't have enough 
resources now to prepare clean enough patch to be accepted by community.
Please find the latest version attached.  Driver has passed stress 
tests, but looks like it need seriuos refactoring (it is 
unnecessarily complicated).
We still have polling in slave code. Since imx doesn't generate 
interrupt on "bus busy"/"bus free" events we have to test IBB bit in 
polling loop.
Comparing to v2 version several race conditions were fixed (bus 
locking by slave, breaking slave transaction by starting master 
xfer). v2 is working pretty good in slave-only or master-only mode. 
It is reasonable to add  slave locking test  - sometimes imx6 hw 
doesn't release data line. As workaround we use dummy reading of 
IMX_I2C_I2DR if driver is in  slave mode and IBB bit is set for a 
long time.


Thanks,
Maxim Syrchin


27.10.2016 10:31, Frkuska, Joshua пишет:

Hi Maxim, Dmitriy, Wolfram,

If there is no immediate plan for a third release of the below patch 
set, would it be possible to continue with merging v2 after 
addressing the remaining concerns?



Thank you and regards,

Joshua

Hi Maxim,

On 2016-03-04 11:06:10 in the thread "Re: [PATCH] i2c: imx: add 
slave support. v2"

referenced here: https://patchwork.ozlabs.org/patch/573353/ you said:

Hi Wolfram,
I'm now working on creating new driver version. I think I'll be 
able to

sent it soon.
Do you still plan to release a driver update for an i2c imx driver 
slave support?


Best regards,
Jim Baxter

Re: [PATCH] i2c: imx: add slave support. v2 status

2016-10-31 Thread Maxim Syrchin 

Hello,

Please find some comments below.


31.10.2016 5:14, Frkuska, Joshua пишет:

Hello Maxim,

Thank you very much for the intermediate patch. I am in the process of 
reviewing it. Please let me clarify a few questions I have.


1. What alternative to "bus busy/bus free/IBB" polling do you have in 
mind? This seems like a reasonable approach to me.
We didn't find any suitable alternatives. The only one we're considered 
was using timeout on receive (which is kind of polling of course)

2. What are the major points you consider in need of refactoring?

As you can see we have implemented FSM in slave thread.
- Due to lack of time all master functionality had not been included in 
State Machine.
- wait_event_timeout() calls are used in every event handler (obviosly 
it is better to have only one wait function)

- Need to review state switching code
3. You mention race conditions being fixed in this version relating to 
bus-locking by the slave and breaking slave transactions by the 
master. Does this mean mixed slave/master mode works to your 
satisfaction? If not, what work still needs to be done here?
Yes mixed slave/master mode works ok. It had passed long-lasting stress 
tests (async message exchange of two imx6 boards connected together by 
i2c bus )
4. You mention the need for a slave locking test and a work-around 
(checking IMX_I2C_I2DR and IBB) being in-place. Why is this 
work-around not sufficient?
By the time we discovered I2DR workaround we went far from version 2 of 
driver and it wasn't tested. I'm sure that I2DR workaround will improve 
stability, but I do not know if it will fix all issues (i.e. passing of 
stress tests )



Best Regards,
Maxim Syrchin

Thanks again,

Joshua


On 10/28/2016 04:38 AM, Maxim Syrchin wrote:

Hi,
Sorry for huge delay in answering. Unfortunately we don't have enough 
resources now to prepare clean enough patch to be accepted by community.
Please find the latest version attached.  Driver has passed stress 
tests, but looks like it need seriuos refactoring (it is 
unnecessarily complicated).
We still have polling in slave code. Since imx doesn't generate 
interrupt on "bus busy"/"bus free" events we have to test IBB bit in 
polling loop.
Comparing to v2 version several race conditions were fixed (bus 
locking by slave, breaking slave transaction by starting master 
xfer). v2 is working pretty good in slave-only or master-only mode. 
It is reasonable to add  slave locking test  - sometimes imx6 hw 
doesn't release data line. As workaround we use dummy reading of 
IMX_I2C_I2DR if driver is in  slave mode and IBB bit is set for a 
long time.


Thanks,
Maxim Syrchin


27.10.2016 10:31, Frkuska, Joshua пишет:

Hi Maxim, Dmitriy, Wolfram,

If there is no immediate plan for a third release of the below patch 
set, would it be possible to continue with merging v2 after 
addressing the remaining concerns?



Thank you and regards,

Joshua

Hi Maxim,

On 2016-03-04 11:06:10 in the thread "Re: [PATCH] i2c: imx: add 
slave support. v2"

referenced here: https://patchwork.ozlabs.org/patch/573353/ you said:

Hi Wolfram,
I'm now working on creating new driver version. I think I'll be 
able to

sent it soon.
Do you still plan to release a driver update for an i2c imx driver 
slave support?


Best regards,
Jim Baxter

Re: [PATCH] i2c: imx: add slave support. v2 status

2016-10-30 Thread Frkuska, Joshua 

Hello Maxim,

Thank you very much for the intermediate patch. I am in the process of 
reviewing it. Please let me clarify a few questions I have.


1. What alternative to "bus busy/bus free/IBB" polling do you have in 
mind? This seems like a reasonable approach to me.

2. What are the major points you consider in need of refactoring?
3. You mention race conditions being fixed in this version relating to 
bus-locking by the slave and breaking slave transactions by the master. 
Does this mean mixed slave/master mode works to your satisfaction? If 
not, what work still needs to be done here?
4. You mention the need for a slave locking test and a work-around 
(checking IMX_I2C_I2DR and IBB) being in-place. Why is this work-around 
not sufficient?


Thanks again,

Joshua


On 10/28/2016 04:38 AM, Maxim Syrchin wrote:

Hi,
Sorry for huge delay in answering. Unfortunately we don't have enough 
resources now to prepare clean enough patch to be accepted by community.
Please find the latest version attached.  Driver has passed stress 
tests, but looks like it need seriuos refactoring (it is unnecessarily 
complicated).
We still have polling in slave code. Since imx doesn't generate 
interrupt on "bus busy"/"bus free" events we have to test IBB bit in 
polling loop.
Comparing to v2 version several race conditions were fixed (bus 
locking by slave, breaking slave transaction by starting master xfer). 
v2 is working pretty good in slave-only or master-only mode. It is 
reasonable to add  slave locking test  - sometimes imx6 hw doesn't 
release data line. As workaround we use dummy reading of IMX_I2C_I2DR 
if driver is in  slave mode and IBB bit is set for a long time.


Thanks,
Maxim Syrchin


27.10.2016 10:31, Frkuska, Joshua пишет:

Hi Maxim, Dmitriy, Wolfram,

If there is no immediate plan for a third release of the below patch 
set, would it be possible to continue with merging v2 after 
addressing the remaining concerns?



Thank you and regards,

Joshua

Hi Maxim,

On 2016-03-04 11:06:10 in the thread "Re: [PATCH] i2c: imx: add 
slave support. v2"

referenced here:   https://patchwork.ozlabs.org/patch/573353/ you said:

Hi Wolfram,
I'm now working on creating new driver version. I think I'll be 
able to

sent it soon.
Do you still plan to release a driver update for an i2c imx driver 
slave support?


Best regards,
Jim Baxter





--
___
Joshua Frkuska | Embedded Software Engineer
Mentor Graphics Japan Co., ltd. | +81-3-6866-7611

PRIVACY AND CONFIDENTIALITY NOTICE
This email and any attachments may contain confidential or privileged 
information for the sole use of the intended recipient.  Any review, reliance 
or distribution by others or forwarding without express permission is strictly 
prohibited.  If you are not the intended recipient, please contact the sender 
and delete all copies.

Re: [PATCH] i2c: imx: add slave support. v2 status

2016-10-30 Thread Frkuska, Joshua 

Hello Maxim,

Thank you very much for the intermediate patch. I am in the process of 
reviewing it. Please let me clarify a few questions I have.


1. What alternative to "bus busy/bus free/IBB" polling do you have in 
mind? This seems like a reasonable approach to me.

2. What are the major points you consider in need of refactoring?
3. You mention race conditions being fixed in this version relating to 
bus-locking by the slave and breaking slave transactions by the master. 
Does this mean mixed slave/master mode works to your satisfaction? If 
not, what work still needs to be done here?
4. You mention the need for a slave locking test and a work-around 
(checking IMX_I2C_I2DR and IBB) being in-place. Why is this work-around 
not sufficient?


Thanks again,

Joshua


On 10/28/2016 04:38 AM, Maxim Syrchin wrote:

Hi,
Sorry for huge delay in answering. Unfortunately we don't have enough 
resources now to prepare clean enough patch to be accepted by community.
Please find the latest version attached.  Driver has passed stress 
tests, but looks like it need seriuos refactoring (it is unnecessarily 
complicated).
We still have polling in slave code. Since imx doesn't generate 
interrupt on "bus busy"/"bus free" events we have to test IBB bit in 
polling loop.
Comparing to v2 version several race conditions were fixed (bus 
locking by slave, breaking slave transaction by starting master xfer). 
v2 is working pretty good in slave-only or master-only mode. It is 
reasonable to add  slave locking test  - sometimes imx6 hw doesn't 
release data line. As workaround we use dummy reading of IMX_I2C_I2DR 
if driver is in  slave mode and IBB bit is set for a long time.


Thanks,
Maxim Syrchin


27.10.2016 10:31, Frkuska, Joshua пишет:

Hi Maxim, Dmitriy, Wolfram,

If there is no immediate plan for a third release of the below patch 
set, would it be possible to continue with merging v2 after 
addressing the remaining concerns?



Thank you and regards,

Joshua

Hi Maxim,

On 2016-03-04 11:06:10 in the thread "Re: [PATCH] i2c: imx: add 
slave support. v2"

referenced here:   https://patchwork.ozlabs.org/patch/573353/ you said:

Hi Wolfram,
I'm now working on creating new driver version. I think I'll be 
able to

sent it soon.
Do you still plan to release a driver update for an i2c imx driver 
slave support?


Best regards,
Jim Baxter





--
___
Joshua Frkuska | Embedded Software Engineer
Mentor Graphics Japan Co., ltd. | +81-3-6866-7611

PRIVACY AND CONFIDENTIALITY NOTICE
This email and any attachments may contain confidential or privileged 
information for the sole use of the intended recipient.  Any review, reliance 
or distribution by others or forwarding without express permission is strictly 
prohibited.  If you are not the intended recipient, please contact the sender 
and delete all copies.

Re: [PATCH] i2c: imx: add slave support. v2 status

2016-10-27 Thread Maxim Syrchin 

Hi,
Sorry for huge delay in answering. Unfortunately we don't have enough 
resources now to prepare clean enough patch to be accepted by community.
Please find the latest version attached.  Driver has passed stress 
tests, but looks like it need seriuos refactoring (it is unnecessarily 
complicated).
We still have polling in slave code. Since imx doesn't generate 
interrupt on "bus busy"/"bus free" events we have to test IBB bit in 
polling loop.
Comparing to v2 version several race conditions were fixed (bus locking 
by slave, breaking slave transaction by starting master xfer). v2 is 
working pretty good in slave-only or master-only mode. It is reasonable 
to add  slave locking test  - sometimes imx6 hw doesn't release data 
line. As workaround we use dummy reading of IMX_I2C_I2DR if driver is 
in  slave mode and IBB bit is set for a long time.


Thanks,
Maxim Syrchin


27.10.2016 10:31, Frkuska, Joshua пишет:

Hi Maxim, Dmitriy, Wolfram,

If there is no immediate plan for a third release of the below patch 
set, would it be possible to continue with merging v2 after addressing 
the remaining concerns?



Thank you and regards,

Joshua

Hi Maxim,

On 2016-03-04 11:06:10 in the thread "Re: [PATCH] i2c: imx: add slave 
support. v2"

referenced here:   https://patchwork.ozlabs.org/patch/573353/ you said:

Hi Wolfram,
I'm now working on creating new driver version. I think I'll be able to
sent it soon.
Do you still plan to release a driver update for an i2c imx driver 
slave support?


Best regards,
Jim Baxter



From 61ae34268d78eb284bf8ee0cbe8f9f0c5e7df074 Mon Sep 17 00:00:00 2001
From: Maxim Syrchin 
Date: Thu, 27 Oct 2016 17:37:56 +0300
Subject: [PATCH] i2c: imx: add slave support. v3

Add I2C slave provider using the generic slave interface.
It also supports master transactions when the slave in the idle mode.

Signed-off-by: Maxim Syrchin 
---
 drivers/i2c/busses/i2c-imx.c | 682 +--
 1 file changed, 653 insertions(+), 29 deletions(-)

diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index 592a8f2..11a2292 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -53,6 +53,7 @@
 #include 
 #include 
 #include 
+#include 
 
 /* This will be the driver name the kernel reports */
 #define DRIVER_NAME "imx-i2c"
@@ -171,6 +172,82 @@ enum imx_i2c_type {
VF610_I2C,
 };
 
+enum i2c_imx_state {
+   STATE_IDLE = 0,
+   STATE_SLAVE,
+   STATE_MASTER,
+   STATE_SP
+};
+
+#define MAX_EVENTS (1<<4)
+#define EUNDEFINED 4000
+
+enum i2c_imx_events {
+   EVT_AL = 0,
+   EVT_SI,
+   EVT_START,
+   EVT_STOP,
+   EVT_POLL,
+   EVT_INVALID,
+   EVT_ENTRY
+};
+
+typedef struct evt_queue {
+   atomic_t count;
+   atomic_t ir;
+   atomic_t iw;
+   unsigned int evt[MAX_EVENTS];
+} evt_queue;
+
+static inline int evt_find_next_idx(atomic_t *v)
+{
+   return atomic_inc_return(v) & (MAX_EVENTS - 1);
+}
+
+static unsigned int evt_put(evt_queue *stk, unsigned int evt)
+{
+   int count = atomic_inc_return(>count);
+   int idx;
+   if (count < MAX_EVENTS)
+   {
+   idx = evt_find_next_idx(>iw);
+   stk->evt[idx] = evt;
+
+   return 0;
+   } else {
+   atomic_dec(>count);
+   return EVT_INVALID;
+   }
+}
+
+static unsigned int evt_get(evt_queue *stk)
+{
+   int count = atomic_dec_return(>count);
+   int idx;
+
+   if (count >= 0)
+   {
+   idx = evt_find_next_idx(>ir);
+   return stk->evt[idx];
+   } else {
+   atomic_inc(>count);
+   return EVT_INVALID;
+   }
+}
+
+static unsigned int evt_is_empty(evt_queue *stk)
+{
+   int ret = atomic_read(>count);
+   return (ret <= 0);
+}
+
+static void evt_init(evt_queue *stk)
+{
+   atomic_set(>count,0);
+   atomic_set(>iw,0);
+   atomic_set(>ir,0);
+}
+
 struct imx_i2c_hwdata {
enum imx_i2c_type   devtype;
unsignedregshift;
@@ -193,6 +270,7 @@ struct imx_i2c_dma {
 
 struct imx_i2c_struct {
struct i2c_adapter  adapter;
+   struct i2c_client   *slave;
struct clk  *clk;
void __iomem*base;
wait_queue_head_t   queue;
@@ -210,6 +288,18 @@ struct imx_i2c_struct {
struct pinctrl_state *pinctrl_pins_gpio;
 
struct imx_i2c_dma  *dma;
+
+   unsigned intstate;
+   evt_queue   events;
+   atomic_tlast_error;
+
+   int master_interrupt;
+   int start_retry_cnt;
+   int slave_poll_cnt;
+
+   struct task_struct  *slave_task;
+   wait_queue_head_t   state_queue;
+
 };
 
 static const struct imx_i2c_hwdata imx1_i2c_hwdata = {
@@ -414,17 +504,31 @@ static void

Re: [PATCH] i2c: imx: add slave support. v2 status

2016-10-27 Thread Maxim Syrchin 

Hi,
Sorry for huge delay in answering. Unfortunately we don't have enough 
resources now to prepare clean enough patch to be accepted by community.
Please find the latest version attached.  Driver has passed stress 
tests, but looks like it need seriuos refactoring (it is unnecessarily 
complicated).
We still have polling in slave code. Since imx doesn't generate 
interrupt on "bus busy"/"bus free" events we have to test IBB bit in 
polling loop.
Comparing to v2 version several race conditions were fixed (bus locking 
by slave, breaking slave transaction by starting master xfer). v2 is 
working pretty good in slave-only or master-only mode. It is reasonable 
to add  slave locking test  - sometimes imx6 hw doesn't release data 
line. As workaround we use dummy reading of IMX_I2C_I2DR if driver is 
in  slave mode and IBB bit is set for a long time.


Thanks,
Maxim Syrchin


27.10.2016 10:31, Frkuska, Joshua пишет:

Hi Maxim, Dmitriy, Wolfram,

If there is no immediate plan for a third release of the below patch 
set, would it be possible to continue with merging v2 after addressing 
the remaining concerns?



Thank you and regards,

Joshua

Hi Maxim,

On 2016-03-04 11:06:10 in the thread "Re: [PATCH] i2c: imx: add slave 
support. v2"

referenced here:   https://patchwork.ozlabs.org/patch/573353/ you said:

Hi Wolfram,
I'm now working on creating new driver version. I think I'll be able to
sent it soon.
Do you still plan to release a driver update for an i2c imx driver 
slave support?


Best regards,
Jim Baxter



From 61ae34268d78eb284bf8ee0cbe8f9f0c5e7df074 Mon Sep 17 00:00:00 2001
From: Maxim Syrchin 
Date: Thu, 27 Oct 2016 17:37:56 +0300
Subject: [PATCH] i2c: imx: add slave support. v3

Add I2C slave provider using the generic slave interface.
It also supports master transactions when the slave in the idle mode.

Signed-off-by: Maxim Syrchin 
---
 drivers/i2c/busses/i2c-imx.c | 682 +--
 1 file changed, 653 insertions(+), 29 deletions(-)

diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index 592a8f2..11a2292 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -53,6 +53,7 @@
 #include 
 #include 
 #include 
+#include 
 
 /* This will be the driver name the kernel reports */
 #define DRIVER_NAME "imx-i2c"
@@ -171,6 +172,82 @@ enum imx_i2c_type {
VF610_I2C,
 };
 
+enum i2c_imx_state {
+   STATE_IDLE = 0,
+   STATE_SLAVE,
+   STATE_MASTER,
+   STATE_SP
+};
+
+#define MAX_EVENTS (1<<4)
+#define EUNDEFINED 4000
+
+enum i2c_imx_events {
+   EVT_AL = 0,
+   EVT_SI,
+   EVT_START,
+   EVT_STOP,
+   EVT_POLL,
+   EVT_INVALID,
+   EVT_ENTRY
+};
+
+typedef struct evt_queue {
+   atomic_t count;
+   atomic_t ir;
+   atomic_t iw;
+   unsigned int evt[MAX_EVENTS];
+} evt_queue;
+
+static inline int evt_find_next_idx(atomic_t *v)
+{
+   return atomic_inc_return(v) & (MAX_EVENTS - 1);
+}
+
+static unsigned int evt_put(evt_queue *stk, unsigned int evt)
+{
+   int count = atomic_inc_return(>count);
+   int idx;
+   if (count < MAX_EVENTS)
+   {
+   idx = evt_find_next_idx(>iw);
+   stk->evt[idx] = evt;
+
+   return 0;
+   } else {
+   atomic_dec(>count);
+   return EVT_INVALID;
+   }
+}
+
+static unsigned int evt_get(evt_queue *stk)
+{
+   int count = atomic_dec_return(>count);
+   int idx;
+
+   if (count >= 0)
+   {
+   idx = evt_find_next_idx(>ir);
+   return stk->evt[idx];
+   } else {
+   atomic_inc(>count);
+   return EVT_INVALID;
+   }
+}
+
+static unsigned int evt_is_empty(evt_queue *stk)
+{
+   int ret = atomic_read(>count);
+   return (ret <= 0);
+}
+
+static void evt_init(evt_queue *stk)
+{
+   atomic_set(>count,0);
+   atomic_set(>iw,0);
+   atomic_set(>ir,0);
+}
+
 struct imx_i2c_hwdata {
enum imx_i2c_type   devtype;
unsignedregshift;
@@ -193,6 +270,7 @@ struct imx_i2c_dma {
 
 struct imx_i2c_struct {
struct i2c_adapter  adapter;
+   struct i2c_client   *slave;
struct clk  *clk;
void __iomem*base;
wait_queue_head_t   queue;
@@ -210,6 +288,18 @@ struct imx_i2c_struct {
struct pinctrl_state *pinctrl_pins_gpio;
 
struct imx_i2c_dma  *dma;
+
+   unsigned intstate;
+   evt_queue   events;
+   atomic_tlast_error;
+
+   int master_interrupt;
+   int start_retry_cnt;
+   int slave_poll_cnt;
+
+   struct task_struct  *slave_task;
+   wait_queue_head_t   state_queue;
+
 };
 
 static const struct imx_i2c_hwdata imx1_i2c_hwdata = {
@@ -414,17 +504,31 @@ static void i2c_imx_dma_free(struct imx_i2c_struct 
*i2c_imx)
 static

Re: Re: [PATCH] i2c: imx: add slave support. v2 status

2016-10-27 Thread Frkuska, Joshua 

Hi Maxim, Dmitriy, Wolfram,

If there is no immediate plan for a third release of the below patch set, would 
it be possible to continue with merging v2 after addressing the remaining 
concerns?


Thank you and regards,

Joshua

Hi Maxim,

On 2016-03-04 11:06:10 in the thread "Re: [PATCH] i2c: imx: add slave support. 
v2"
referenced here:   https://patchwork.ozlabs.org/patch/573353/  you said:

Hi Wolfram,
I'm now working on creating new driver version. I think I'll be able to
sent it soon.

Do you still plan to release a driver update for an i2c imx driver slave 
support?

Best regards,
Jim Baxter

Re: Re: [PATCH] i2c: imx: add slave support. v2 status

2016-10-27 Thread Frkuska, Joshua 

Hi Maxim, Dmitriy, Wolfram,

If there is no immediate plan for a third release of the below patch set, would 
it be possible to continue with merging v2 after addressing the remaining 
concerns?


Thank you and regards,

Joshua

Hi Maxim,

On 2016-03-04 11:06:10 in the thread "Re: [PATCH] i2c: imx: add slave support. 
v2"
referenced here:   https://patchwork.ozlabs.org/patch/573353/  you said:

Hi Wolfram,
I'm now working on creating new driver version. I think I'll be able to
sent it soon.

Do you still plan to release a driver update for an i2c imx driver slave 
support?

Best regards,
Jim Baxter