[PATCH v3 2/5] i3c: master: make sure ->boardinfo is initialized in add_i3c_dev_locked()

[PATCH v3 2/5] i3c: master: make sure ->boardinfo is initialized in add_i3c_dev_locked()

[Vitor Soares]

The newdev->boardinfo assignment was missing in
i3c_master_add_i3c_dev_locked() and hence the ->of_node info isn't
propagated to i3c_dev_desc.

Fix this by trying to initialize device i3c_dev_boardinfo if available.

Cc: <stable@vger.kernel.org>
Fixes: 3a379bbcea0a ("i3c: Add core I3C infrastructure")
Signed-off-by: Vitor Soares <vitor.soares@synopsys.com>
---
Change in v3:
  - None

Changes in v2:
  - Change commit message
  - Change i3c_master_search_i3c_boardinfo(newdev) to
  i3c_master_init_i3c_dev_boardinfo(newdev)
  - Add fixes, stable tags

 drivers/i3c/master.c | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index 586e34f..9fb99bc 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -1798,6 +1798,22 @@ i3c_master_search_i3c_dev_duplicate(struct i3c_dev_desc *refdev)
 	return NULL;
 }
 
+static void i3c_master_init_i3c_dev_boardinfo(struct i3c_dev_desc *dev)
+{
+	struct i3c_master_controller *master = i3c_dev_get_master(dev);
+	struct i3c_dev_boardinfo *boardinfo;
+
+	if (dev->boardinfo)
+		return;
+
+	list_for_each_entry(boardinfo, &master->boardinfo.i3c, node) {
+		if (dev->info.pid == boardinfo->pid) {
+			dev->boardinfo = boardinfo;
+			return;
+		}
+	}
+}
+
 /**
  * i3c_master_add_i3c_dev_locked() - add an I3C slave to the bus
  * @master: master used to send frames on the bus
@@ -1818,8 +1834,9 @@ int i3c_master_add_i3c_dev_locked(struct i3c_master_controller *master,
 				  u8 addr)
 {
 	struct i3c_device_info info = { .dyn_addr = addr };
-	struct i3c_dev_desc *newdev, *olddev;
 	u8 old_dyn_addr = addr, expected_dyn_addr;
+	enum i3c_addr_slot_status addrstatus;
+	struct i3c_dev_desc *newdev, *olddev;
 	struct i3c_ibi_setup ibireq = { };
 	bool enable_ibi = false;
 	int ret;
@@ -1878,6 +1895,8 @@ int i3c_master_add_i3c_dev_locked(struct i3c_master_controller *master,
 	if (ret)
 		goto err_detach_dev;
 
+	i3c_master_init_i3c_dev_boardinfo(newdev);
+
 	/*
 	 * Depending on our previous state, the expected dynamic address might
 	 * differ:
@@ -1895,7 +1914,11 @@ int i3c_master_add_i3c_dev_locked(struct i3c_master_controller *master,
 	else
 		expected_dyn_addr = newdev->info.dyn_addr;
 
-	if (newdev->info.dyn_addr != expected_dyn_addr) {
+	addrstatus = i3c_bus_get_addr_slot_status(&master->bus,
+						  expected_dyn_addr);
+
+	if (newdev->info.dyn_addr != expected_dyn_addr &&
+	    addrstatus == I3C_ADDR_SLOT_FREE) {
 		/*
 		 * Try to apply the expected dynamic address. If it fails, keep
 		 * the address assigned by the master.
-- 
2.7.4

Re: [PATCH v3 2/5] i3c: master: make sure ->boardinfo is initialized in add_i3c_dev_locked()

[Boris Brezillon]

On Thu,  5 Sep 2019 12:00:35 +0200
Vitor Soares <Vitor.Soares@synopsys.com> wrote:

> The newdev->boardinfo assignment was missing in
> i3c_master_add_i3c_dev_locked() and hence the ->of_node info isn't
> propagated to i3c_dev_desc.
> 
> Fix this by trying to initialize device i3c_dev_boardinfo if available.
> 
> Cc: <stable@vger.kernel.org>
> Fixes: 3a379bbcea0a ("i3c: Add core I3C infrastructure")
> Signed-off-by: Vitor Soares <vitor.soares@synopsys.com>
> ---
> Change in v3:
>   - None
> 
> Changes in v2:
>   - Change commit message
>   - Change i3c_master_search_i3c_boardinfo(newdev) to
>   i3c_master_init_i3c_dev_boardinfo(newdev)
>   - Add fixes, stable tags
> 
>  drivers/i3c/master.c | 27 +++++++++++++++++++++++++--
>  1 file changed, 25 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
> index 586e34f..9fb99bc 100644
> --- a/drivers/i3c/master.c
> +++ b/drivers/i3c/master.c
> @@ -1798,6 +1798,22 @@ i3c_master_search_i3c_dev_duplicate(struct i3c_dev_desc *refdev)
>  	return NULL;
>  }
>  
> +static void i3c_master_init_i3c_dev_boardinfo(struct i3c_dev_desc *dev)
> +{
> +	struct i3c_master_controller *master = i3c_dev_get_master(dev);
> +	struct i3c_dev_boardinfo *boardinfo;
> +
> +	if (dev->boardinfo)
> +		return;
> +
> +	list_for_each_entry(boardinfo, &master->boardinfo.i3c, node) {
> +		if (dev->info.pid == boardinfo->pid) {
> +			dev->boardinfo = boardinfo;
> +			return;
> +		}
> +	}
> +}
> +
>  /**
>   * i3c_master_add_i3c_dev_locked() - add an I3C slave to the bus
>   * @master: master used to send frames on the bus
> @@ -1818,8 +1834,9 @@ int i3c_master_add_i3c_dev_locked(struct i3c_master_controller *master,
>  				  u8 addr)
>  {
>  	struct i3c_device_info info = { .dyn_addr = addr };
> -	struct i3c_dev_desc *newdev, *olddev;
>  	u8 old_dyn_addr = addr, expected_dyn_addr;
> +	enum i3c_addr_slot_status addrstatus;
> +	struct i3c_dev_desc *newdev, *olddev;
>  	struct i3c_ibi_setup ibireq = { };
>  	bool enable_ibi = false;
>  	int ret;
> @@ -1878,6 +1895,8 @@ int i3c_master_add_i3c_dev_locked(struct i3c_master_controller *master,
>  	if (ret)
>  		goto err_detach_dev;
>  
> +	i3c_master_init_i3c_dev_boardinfo(newdev);
> +
>  	/*
>  	 * Depending on our previous state, the expected dynamic address might
>  	 * differ:
> @@ -1895,7 +1914,11 @@ int i3c_master_add_i3c_dev_locked(struct i3c_master_controller *master,
>  	else
>  		expected_dyn_addr = newdev->info.dyn_addr;
>  
> -	if (newdev->info.dyn_addr != expected_dyn_addr) {
> +	addrstatus = i3c_bus_get_addr_slot_status(&master->bus,
> +						  expected_dyn_addr);
> +
> +	if (newdev->info.dyn_addr != expected_dyn_addr &&
> +	    addrstatus == I3C_ADDR_SLOT_FREE) {

First, this change shouldn't be part of this patch, since the commit
message only mentions the boardinfo init stuff, not the extra 'is slot
free check'. Plus, I want the fix to be backported so we should avoid
any unneeded deps.

But even with those 2 things addressed, I'm still convinced the
'free desc when device is not reachable' change you do in patch 1 is
not that great, and the fact that you can't pre-reserve the address to
make sure no one uses it until the device had a chance to show up tends
to prove me right.

Can we please do what I suggest and solve the "not enough dev slots"
problem later on (if we really have to).

>  		/*
>  		 * Try to apply the expected dynamic address. If it fails, keep
>  		 * the address assigned by the master.

RE: [PATCH v3 2/5] i3c: master: make sure ->boardinfo is initialized in add_i3c_dev_locked()

[Vitor Soares]

Hi Boris,

From: Boris Brezillon <boris.brezillon@collabora.com>
Date: Thu, Oct 03, 2019 at 15:29:43

> On Thu,  5 Sep 2019 12:00:35 +0200
> Vitor Soares <Vitor.Soares@synopsys.com> wrote:
> 
> > The newdev->boardinfo assignment was missing in
> > i3c_master_add_i3c_dev_locked() and hence the ->of_node info isn't
> > propagated to i3c_dev_desc.
> > 
> > Fix this by trying to initialize device i3c_dev_boardinfo if available.
> > 
> > Cc: <stable@vger.kernel.org>
> > Fixes: 3a379bbcea0a ("i3c: Add core I3C infrastructure")
> > Signed-off-by: Vitor Soares <vitor.soares@synopsys.com>
> > ---
> > Change in v3:
> >   - None
> > 
> > Changes in v2:
> >   - Change commit message
> >   - Change i3c_master_search_i3c_boardinfo(newdev) to
> >   i3c_master_init_i3c_dev_boardinfo(newdev)
> >   - Add fixes, stable tags
> > 
> >  /**
> >   * i3c_master_add_i3c_dev_locked() - add an I3C slave to the bus
> >   * @master: master used to send frames on the bus
> > @@ -1818,8 +1834,9 @@ int i3c_master_add_i3c_dev_locked(struct i3c_master_controller *master,
> >  				  u8 addr)
> >  {
> >  	struct i3c_device_info info = { .dyn_addr = addr };
> > -	struct i3c_dev_desc *newdev, *olddev;
> >  	u8 old_dyn_addr = addr, expected_dyn_addr;
> > +	enum i3c_addr_slot_status addrstatus;
> > +	struct i3c_dev_desc *newdev, *olddev;
> >  	struct i3c_ibi_setup ibireq = { };
> >  	bool enable_ibi = false;
> >  	int ret;
> > @@ -1878,6 +1895,8 @@ int i3c_master_add_i3c_dev_locked(struct i3c_master_controller *master,
> >  	if (ret)
> >  		goto err_detach_dev;
> >  
> > +	i3c_master_init_i3c_dev_boardinfo(newdev);
> > +
> >  	/*
> >  	 * Depending on our previous state, the expected dynamic address might
> >  	 * differ:
> > @@ -1895,7 +1914,11 @@ int i3c_master_add_i3c_dev_locked(struct i3c_master_controller *master,
> >  	else
> >  		expected_dyn_addr = newdev->info.dyn_addr;
> >  
> > -	if (newdev->info.dyn_addr != expected_dyn_addr) {
> > +	addrstatus = i3c_bus_get_addr_slot_status(&master->bus,
> > +						  expected_dyn_addr);
> > +
> > +	if (newdev->info.dyn_addr != expected_dyn_addr &&
> > +	    addrstatus == I3C_ADDR_SLOT_FREE) {
> 
> First, this change shouldn't be part of this patch, since the commit
> message only mentions the boardinfo init stuff,

This is not an issue, I can create a patch just for boardinfo init fix.

> not the extra 'is slot
> free check'.

Even ignoring patch 1, it is necessary to check if the slot is free 
because if SETDASA fails the boardinfo->init_dyn_addr can be assigned to 
another device. That's why we need to check if expected_dyn_addr is free.

> Plus, I want the fix to be backported so we should avoid
> any unneeded deps.
> 
> But even with those 2 things addressed, I'm still convinced the
> 'free desc when device is not reachable' change you do in patch 1 is
> not that great, 

If I'm doing wrong I really appreciate you tell me the reason.

> and the fact that you can't pre-reserve the address to
> make sure no one uses it until the device had a chance to show up tends
> to prove me right.

This is a different corner case and I though we agreed that the framework 
doesn't provide guarantees to assign boardinfo->init_dyn_addr [1].

Yet, I don't disagree with the idea of pre-reserve the 
boardinfo->init_dyn_addr.
I can do this but we need to align how it should be done.

> 
> Can we please do what I suggest and solve the "not enough dev slots"
> problem later on (if we really have to).

I have this use case where the HC has only 4 slot for 4 devices. 
Sometimes the one or more devices can be sleeping and when they trigger 
HJ there is no space in HC.

Best regards,
Vitor Soares

[1] https://patchwork.kernel.org/patch/11120841/

Re: [PATCH v3 2/5] i3c: master: make sure ->boardinfo is initialized in add_i3c_dev_locked()

[Boris Brezillon]

On Thu, 3 Oct 2019 17:37:40 +0000
Vitor Soares <Vitor.Soares@synopsys.com> wrote:

> Hi Boris,
> 
> From: Boris Brezillon <boris.brezillon@collabora.com>
> Date: Thu, Oct 03, 2019 at 15:29:43
> 
> > On Thu,  5 Sep 2019 12:00:35 +0200
> > Vitor Soares <Vitor.Soares@synopsys.com> wrote:
> >   
> > > The newdev->boardinfo assignment was missing in
> > > i3c_master_add_i3c_dev_locked() and hence the ->of_node info isn't
> > > propagated to i3c_dev_desc.
> > > 
> > > Fix this by trying to initialize device i3c_dev_boardinfo if available.
> > > 
> > > Cc: <stable@vger.kernel.org>
> > > Fixes: 3a379bbcea0a ("i3c: Add core I3C infrastructure")
> > > Signed-off-by: Vitor Soares <vitor.soares@synopsys.com>
> > > ---
> > > Change in v3:
> > >   - None
> > > 
> > > Changes in v2:
> > >   - Change commit message
> > >   - Change i3c_master_search_i3c_boardinfo(newdev) to
> > >   i3c_master_init_i3c_dev_boardinfo(newdev)
> > >   - Add fixes, stable tags
> > > 
> > >  /**
> > >   * i3c_master_add_i3c_dev_locked() - add an I3C slave to the bus
> > >   * @master: master used to send frames on the bus
> > > @@ -1818,8 +1834,9 @@ int i3c_master_add_i3c_dev_locked(struct i3c_master_controller *master,
> > >  				  u8 addr)
> > >  {
> > >  	struct i3c_device_info info = { .dyn_addr = addr };
> > > -	struct i3c_dev_desc *newdev, *olddev;
> > >  	u8 old_dyn_addr = addr, expected_dyn_addr;
> > > +	enum i3c_addr_slot_status addrstatus;
> > > +	struct i3c_dev_desc *newdev, *olddev;
> > >  	struct i3c_ibi_setup ibireq = { };
> > >  	bool enable_ibi = false;
> > >  	int ret;
> > > @@ -1878,6 +1895,8 @@ int i3c_master_add_i3c_dev_locked(struct i3c_master_controller *master,
> > >  	if (ret)
> > >  		goto err_detach_dev;
> > >  
> > > +	i3c_master_init_i3c_dev_boardinfo(newdev);
> > > +
> > >  	/*
> > >  	 * Depending on our previous state, the expected dynamic address might
> > >  	 * differ:
> > > @@ -1895,7 +1914,11 @@ int i3c_master_add_i3c_dev_locked(struct i3c_master_controller *master,
> > >  	else
> > >  		expected_dyn_addr = newdev->info.dyn_addr;
> > >  
> > > -	if (newdev->info.dyn_addr != expected_dyn_addr) {
> > > +	addrstatus = i3c_bus_get_addr_slot_status(&master->bus,
> > > +						  expected_dyn_addr);
> > > +
> > > +	if (newdev->info.dyn_addr != expected_dyn_addr &&
> > > +	    addrstatus == I3C_ADDR_SLOT_FREE) {  
> > 
> > First, this change shouldn't be part of this patch, since the commit
> > message only mentions the boardinfo init stuff,  
> 
> This is not an issue, I can create a patch just for boardinfo init fix.
> 
> > not the extra 'is slot
> > free check'.  
> 
> Even ignoring patch 1, it is necessary to check if the slot is free 
> because if SETDASA fails the boardinfo->init_dyn_addr can be assigned to 
> another device. That's why we need to check if expected_dyn_addr is free.

Correct. I thought we were already pre-reserving the init_addr (as
described here [1]), but it looks like the code is buggy. That's
probably something we should fix  (we should reserve ->init_i3c_addr
here [2], not ->dyn_addr).

> 
> > Plus, I want the fix to be backported so we should avoid
> > any unneeded deps.
> > 
> > But even with those 2 things addressed, I'm still convinced the
> > 'free desc when device is not reachable' change you do in patch 1 is
> > not that great,   
> 
> If I'm doing wrong I really appreciate you tell me the reason.

I just think it's easier to keep track of things (like reserved
addresses) if the descriptor stays around even if the device is not yet
accessible.

> 
> > and the fact that you can't pre-reserve the address to
> > make sure no one uses it until the device had a chance to show up tends
> > to prove me right.  
> 
> This is a different corner case and I though we agreed that the framework 
> doesn't provide guarantees to assign boardinfo->init_dyn_addr [1].

Well, it doesn't, but we should try hard to not use addresses that
have been requested by a device.

> 
> Yet, I don't disagree with the idea of pre-reserve the 
> boardinfo->init_dyn_addr.
> I can do this but we need to align how it should be done.

Keep the device around even if SETDASA fails and make sure the
->init_dyn_addr is reserved. It's how it was supposed to work, there's
just a bug in the logic.

> 
> > 
> > Can we please do what I suggest and solve the "not enough dev slots"
> > problem later on (if we really have to).  
> 
> I have this use case where the HC has only 4 slot for 4 devices. 
> Sometimes the one or more devices can be sleeping and when they trigger 
> HJ there is no space in HC.

Let's address that separately please. I want to solve one problem at a
time.

[1]https://elixir.bootlin.com/linux/latest/source/drivers/i3c/master.c#L1330
[2]https://elixir.bootlin.com/linux/latest/source/drivers/i3c/master.c#L1307