[dpdk-dev] [PATCH v3 1/2] ethdev: add callback to get register size in bytes

[dpdk-dev] [PATCH v3 1/2] ethdev: add callback to get register size in bytes

[zr]

From: Zyta Szpak <zr@semihalf.com>

Version 2 of fixing the fixed register width assumption.
rte_eth_dev_get_reg_length and rte_eth_dev_get_reg callbacks
do not provide register size to the app in any way. It is
needed to allocate proper number of bytes before retrieving
registers content with rte_eth_dev_get_reg.

Signed-off-by: Zyta Szpak <zr@semihalf.com>
---
 lib/librte_ether/rte_ethdev.c          | 12 ++++++++++++
 lib/librte_ether/rte_ethdev.h          | 18 ++++++++++++++++++
 lib/librte_ether/rte_ether_version.map |  7 +++++++
 3 files changed, 37 insertions(+)

diff --git a/lib/librte_ether/rte_ethdev.c b/lib/librte_ether/rte_ethdev.c
index a31018e..e0765f8 100644
--- a/lib/librte_ether/rte_ethdev.c
+++ b/lib/librte_ether/rte_ethdev.c
@@ -3231,6 +3231,18 @@ rte_eth_dev_get_reg_length(uint8_t port_id)
 }
 
 int
+rte_eth_dev_get_reg_width(uint8_t port_id)
+{
+	struct rte_eth_dev *dev;
+
+	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
+
+	dev = &rte_eth_devices[port_id];
+	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->get_reg_width, -ENOTSUP);
+	return (*dev->dev_ops->get_reg_width)(dev);
+}
+
+int
 rte_eth_dev_get_reg_info(uint8_t port_id, struct rte_dev_reg_info *info)
 {
 	struct rte_eth_dev *dev;
diff --git a/lib/librte_ether/rte_ethdev.h b/lib/librte_ether/rte_ethdev.h
index 2757510..552eaed 100644
--- a/lib/librte_ether/rte_ethdev.h
+++ b/lib/librte_ether/rte_ethdev.h
@@ -1292,6 +1292,9 @@ typedef int (*eth_timesync_write_time)(struct rte_eth_dev *dev,
 typedef int (*eth_get_reg_length_t)(struct rte_eth_dev *dev);
 /**< @internal Retrieve device register count  */
 
+typedef int (*eth_get_reg_width_t)(struct rte_eth_dev *dev);
+/**< @internal Retrieve device register byte number */
+
 typedef int (*eth_get_reg_t)(struct rte_eth_dev *dev,
 				struct rte_dev_reg_info *info);
 /**< @internal Retrieve registers  */
@@ -1455,6 +1458,8 @@ struct eth_dev_ops {
 
 	eth_get_reg_length_t get_reg_length;
 	/**< Get # of registers */
+	eth_get_reg_width_t get_reg_width;
+	/**< Get # of bytes in register */
 	eth_get_reg_t get_reg;
 	/**< Get registers */
 	eth_get_eeprom_length_t get_eeprom_length;
@@ -3971,6 +3976,19 @@ int rte_eth_tx_queue_info_get(uint8_t port_id, uint16_t queue_id,
  */
 int rte_eth_dev_get_reg_length(uint8_t port_id);
 
+/*
+ * Retrieve the number of bytes in register for a specific device
+ *
+ * @param port_id
+ *   The port identifier of the Ethernet device.
+ * @return
+ *   - (>=0) number of registers if successful.
+ *   - (-ENOTSUP) if hardware doesn't support.
+ *   - (-ENODEV) if *port_id* invalid.
+ *   - others depends on the specific operations implementation.
+ */
+int rte_eth_dev_get_reg_width(uint8_t port_id);
+
 /**
  * Retrieve device registers and register attributes
  *
diff --git a/lib/librte_ether/rte_ether_version.map b/lib/librte_ether/rte_ether_version.map
index 214ecc7..568509c 100644
--- a/lib/librte_ether/rte_ether_version.map
+++ b/lib/librte_ether/rte_ether_version.map
@@ -132,3 +132,10 @@ DPDK_16.04 {
 	rte_eth_tx_buffer_set_err_callback;
 
 } DPDK_2.2;
+
+DPDK_16.07 {
+	global:
+
+	rte_eth_dev_get_reg_width;
+
+} DPDK_16.04;
\ No newline at end of file
-- 
1.9.1

[dpdk-dev] [PATCH v3 2/2] examples/ethtool: get reg width to allocate memory

[zr]

From: Zyta Szpak <zr@semihalf.com>

Version 2 of fixing the fixed register width assumption.
Not every device uses 32-bit wide register. The app was allocating too
little space for 64-bit registers which resulted in memory corruption.
This commit resolves this by getting the size of register in bytes for
a specific device. If the device does not implement this function, it
fallsback to sizeof(uint32_t)

Signed-off-by: Zyta Szpak <zr@semihalf.com>
---
 examples/ethtool/lib/rte_ethtool.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/examples/ethtool/lib/rte_ethtool.c b/examples/ethtool/lib/rte_ethtool.c
index 42e05f1..59191ca 100644
--- a/examples/ethtool/lib/rte_ethtool.c
+++ b/examples/ethtool/lib/rte_ethtool.c
@@ -88,10 +88,14 @@ int
 rte_ethtool_get_regs_len(uint8_t port_id)
 {
 	int count_regs;
+	int reg_width;
 
 	count_regs = rte_eth_dev_get_reg_length(port_id);
+	reg_width = rte_eth_dev_get_reg_width(port_id);
+	if (reg_width < 0)
+		reg_width = sizeof(uint32_t);
 	if (count_regs > 0)
-		return count_regs * sizeof(uint32_t);
+		return count_regs * reg_width;
 	return count_regs;
 }
 
-- 
1.9.1

Re: [dpdk-dev] [PATCH v3 2/2] examples/ethtool: get reg width to allocate memory

[Remy Horton]

On 01/06/2016 08:56, zr@semihalf.com wrote:
> From: Zyta Szpak <zr@semihalf.com>
>
> Version 2 of fixing the fixed register width assumption.
> Not every device uses 32-bit wide register. The app was allocating too
> little space for 64-bit registers which resulted in memory corruption.
> This commit resolves this by getting the size of register in bytes for
> a specific device. If the device does not implement this function, it
> fallsback to sizeof(uint32_t)
>
> Signed-off-by: Zyta Szpak <zr@semihalf.com>

Acked-by: Remy Horton <remy.horton@intel.com>

Re: [dpdk-dev] [PATCH v3 1/2] ethdev: add callback to get register size in bytes

[Remy Horton]

On 01/06/2016 08:56, zr@semihalf.com wrote:
> From: Zyta Szpak <zr@semihalf.com>
>
> Version 2 of fixing the fixed register width assumption.
> rte_eth_dev_get_reg_length and rte_eth_dev_get_reg callbacks
> do not provide register size to the app in any way. It is
> needed to allocate proper number of bytes before retrieving
> registers content with rte_eth_dev_get_reg.
>
> Signed-off-by: Zyta Szpak <zr@semihalf.com>

Acked-by: Remy Horton <remy.horton@intel.com>

Re: [dpdk-dev] [PATCH v3 1/2] ethdev: add callback to get register size in bytes

[Thomas Monjalon]

Hi Zyta,

2016-06-01 09:56, zr@semihalf.com:
> rte_eth_dev_get_reg_length and rte_eth_dev_get_reg callbacks
> do not provide register size to the app in any way. It is
> needed to allocate proper number of bytes before retrieving
> registers content with rte_eth_dev_get_reg.

Yes, register size is needed.
And I think it makes sense to register it in the struct rte_dev_reg_info.
We already have a length field, so we could just add a width field.

> @@ -1455,6 +1458,8 @@ struct eth_dev_ops {
>  
>  	eth_get_reg_length_t get_reg_length;
>  	/**< Get # of registers */
> +	eth_get_reg_width_t get_reg_width;
> +	/**< Get # of bytes in register */
>  	eth_get_reg_t get_reg;
>  	/**< Get registers */

I am not sure it is a good practice to add a new function for each
parameter of a request.
I would prefer having only one function rte_eth_dev_get_regs()
which returns length and width if data is NULL.
The first call is a parameter request before buffer allocation,
and the second call fills the buffer.

We can deprecate the old API and introduce this new one.

Opinions?

Re: [dpdk-dev] [PATCH v3 1/2] ethdev: add callback to get register size in bytes

[Zyta Szpak]

Hi,
please see inline

2016-06-08 10:53 GMT+02:00 Thomas Monjalon <thomas.monjalon@6wind.com>:

> Hi Zyta,
>
> 2016-06-01 09:56, zr@semihalf.com:
> > rte_eth_dev_get_reg_length and rte_eth_dev_get_reg callbacks
> > do not provide register size to the app in any way. It is
> > needed to allocate proper number of bytes before retrieving
> > registers content with rte_eth_dev_get_reg.
>
> Yes, register size is needed.
> And I think it makes sense to register it in the struct rte_dev_reg_info.
> We already have a length field, so we could just add a width field.
>
That was my first thought to add reg_size to reg_info struct but
get_reg_length doesn' take reg_info as parameter so it would require
modification of this callback as well. This would interfere with the
author's vision. I think that adding a new one is clear and readable.

>
> > @@ -1455,6 +1458,8 @@ struct eth_dev_ops {
> >
> >       eth_get_reg_length_t get_reg_length;
> >       /**< Get # of registers */
> > +     eth_get_reg_width_t get_reg_width;
> > +     /**< Get # of bytes in register */
> >       eth_get_reg_t get_reg;
> >       /**< Get registers */
>
> I am not sure it is a good practice to add a new function for each
> parameter of a request.
> I would prefer having only one function rte_eth_dev_get_regs()
> which returns length and width if data is NULL.
> The first call is a parameter request before buffer allocation,
> and the second call fills the buffer.
>
> We can deprecate the old API and introduce this new one.
>
> Opinions?
>

In my opinion as it is now it works fine. Gathering all parameters in one
callback might be a good idea if the maintainer also agrees to that because
as I mentioned, it interferes.
Any other opinions?\

Best regards,
Zyta Szpak

Re: [dpdk-dev] [PATCH v3 1/2] ethdev: add callback to get register size in bytes

[Remy Horton]

On 12/06/2016 15:51, Zyta Szpak wrote:
>     I would prefer having only one function rte_eth_dev_get_regs()
>     which returns length and width if data is NULL.
>     The first call is a parameter request before buffer allocation,
>     and the second call fills the buffer.
>
>     We can deprecate the old API and introduce this new one.
>
>     Opinions?
>
> In my opinion as it is now it works fine. Gathering all parameters in
> one callback might be a good idea if the maintainer also agrees to that
> because as I mentioned, it interferes.

 From my perspective changing rte_eth_dev_get_regs() isn't a problem, as 
it isn't used directly rather than through rte_ethtool_get_regs()..

..Remy

Re: [dpdk-dev] [PATCH v3 1/2] ethdev: add callback to get register size in bytes

[Thomas Monjalon]

2016-06-13 16:51, Remy Horton:
> 
> On 12/06/2016 15:51, Zyta Szpak wrote:
> >     I would prefer having only one function rte_eth_dev_get_regs()
> >     which returns length and width if data is NULL.
> >     The first call is a parameter request before buffer allocation,
> >     and the second call fills the buffer.
> >
> >     We can deprecate the old API and introduce this new one.
> >
> >     Opinions?
> >
> > In my opinion as it is now it works fine. Gathering all parameters in
> > one callback might be a good idea if the maintainer also agrees to that
> > because as I mentioned, it interferes.
> 
>  From my perspective changing rte_eth_dev_get_regs() isn't a problem, as 
> it isn't used directly rather than through rte_ethtool_get_regs()..

Zyta, would you like to make a v4?

Re: [dpdk-dev] [PATCH v3 1/2] ethdev: add callback to get register size in bytes

[Zyta Szpak]

OK, I will do the v4.

On 17.06.2016 12:20, Thomas Monjalon wrote:
> 2016-06-13 16:51, Remy Horton:
>> On 12/06/2016 15:51, Zyta Szpak wrote:
>>>      I would prefer having only one function rte_eth_dev_get_regs()
>>>      which returns length and width if data is NULL.
>>>      The first call is a parameter request before buffer allocation,
>>>      and the second call fills the buffer.
>>>
>>>      We can deprecate the old API and introduce this new one.
>>>
>>>      Opinions?
>>>
>>> In my opinion as it is now it works fine. Gathering all parameters in
>>> one callback might be a good idea if the maintainer also agrees to that
>>> because as I mentioned, it interferes.
>>   From my perspective changing rte_eth_dev_get_regs() isn't a problem, as
>> it isn't used directly rather than through rte_ethtool_get_regs()..
> Zyta, would you like to make a v4?

Re: [dpdk-dev] [PATCH v3 1/2] ethdev: add callback to get register size in bytes

[Zyta Szpak]

Note that if we remove rte_eth_dev_get_reg_length() then it will break 
all of the drivers that implement it. Shall I remove it all leave it and 
modify only ethtool to use rte_eth_dev_get_regs() to get reg size? In 
the end the drivers will have to implement the part of setting the size 
in reg_info struct. rte_eth_dev_get_regs() itself wouldn't change at all.
Or do you have different opinion?

On 21.06.2016 11:55, Zyta Szpak wrote:
> OK, I will do the v4.
>
> On 17.06.2016 12:20, Thomas Monjalon wrote:
>> 2016-06-13 16:51, Remy Horton:
>>> On 12/06/2016 15:51, Zyta Szpak wrote:
>>>>      I would prefer having only one function rte_eth_dev_get_regs()
>>>>      which returns length and width if data is NULL.
>>>>      The first call is a parameter request before buffer allocation,
>>>>      and the second call fills the buffer.
>>>>
>>>>      We can deprecate the old API and introduce this new one.
>>>>
>>>>      Opinions?
>>>>
>>>> In my opinion as it is now it works fine. Gathering all parameters in
>>>> one callback might be a good idea if the maintainer also agrees to 
>>>> that
>>>> because as I mentioned, it interferes.
>>>   From my perspective changing rte_eth_dev_get_regs() isn't a 
>>> problem, as
>>> it isn't used directly rather than through rte_ethtool_get_regs()..
>> Zyta, would you like to make a v4?
>

Re: [dpdk-dev] [PATCH v3 1/2] ethdev: add callback to get register size in bytes

[Thomas Monjalon]

2016-06-22 10:19, Zyta Szpak:
> Note that if we remove rte_eth_dev_get_reg_length() then it will break 
> all of the drivers that implement it. Shall I remove it all leave it and 
> modify only ethtool to use rte_eth_dev_get_regs() to get reg size? In 
> the end the drivers will have to implement the part of setting the size 
> in reg_info struct. rte_eth_dev_get_regs() itself wouldn't change at all.
> Or do you have different opinion?

igb, ixgbe and i40e must be updated in the same patch to comply with the
new behaviour of rte_eth_dev_get_regs.
rte_eth_dev_get_reg_length can be deprecated and removed in the next release.


> On 21.06.2016 11:55, Zyta Szpak wrote:
> > OK, I will do the v4.
> >
> > On 17.06.2016 12:20, Thomas Monjalon wrote:
> >> 2016-06-13 16:51, Remy Horton:
> >>> On 12/06/2016 15:51, Zyta Szpak wrote:
> >>>>      I would prefer having only one function rte_eth_dev_get_regs()
> >>>>      which returns length and width if data is NULL.
> >>>>      The first call is a parameter request before buffer allocation,
> >>>>      and the second call fills the buffer.
> >>>>
> >>>>      We can deprecate the old API and introduce this new one.
> >>>>
> >>>>      Opinions?
> >>>>
> >>>> In my opinion as it is now it works fine. Gathering all parameters in
> >>>> one callback might be a good idea if the maintainer also agrees to 
> >>>> that
> >>>> because as I mentioned, it interferes.
> >>>   From my perspective changing rte_eth_dev_get_regs() isn't a 
> >>> problem, as
> >>> it isn't used directly rather than through rte_ethtool_get_regs()..
> >> Zyta, would you like to make a v4?
> >
>