[PATCH net] mscc: Register poll timeout should be wall time not attempts

[PATCH net] mscc: Register poll timeout should be wall time not attempts

[Steen Hegelund]

When doing indirect access in the Ocelot chip, a command is setup,
issued and then we need to poll until the result is ready. The polling
timeout is specified in milliseconds in the datasheet and not in
register access attempts.

Signed-off-by: Steen Hegelund <steen.hegelund@microchip.com>
---
 drivers/net/ethernet/mscc/ocelot.c | 55 +++++++++++++++---------------
 1 file changed, 27 insertions(+), 28 deletions(-)

diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c
index 3238b9ee42f3..debe74e4a041 100644
--- a/drivers/net/ethernet/mscc/ocelot.c
+++ b/drivers/net/ethernet/mscc/ocelot.c
@@ -15,6 +15,7 @@
 #include <linux/netdevice.h>
 #include <linux/phy.h>
 #include <linux/skbuff.h>
+#include <linux/iopoll.h>
 #include <net/arp.h>
 #include <net/netevent.h>
 #include <net/rtnetlink.h>
@@ -22,6 +23,9 @@
 
 #include "ocelot.h"
 
+#define TABLE_UPDATE_SLEEP_US 10
+#define TABLE_UPDATE_TIMEOUT_US 100000
+
 /* MAC table entry types.
  * ENTRYTYPE_NORMAL is subject to aging.
  * ENTRYTYPE_LOCKED is not subject to aging.
@@ -41,23 +45,20 @@ struct ocelot_mact_entry {
 	enum macaccess_entry_type type;
 };
 
-static inline int ocelot_mact_wait_for_completion(struct ocelot *ocelot)
+static inline u32 ocelot_mact_read_macaccess(struct ocelot *ocelot)
 {
-	unsigned int val, timeout = 10;
-
-	/* Wait for the issued mac table command to be completed, or timeout.
-	 * When the command read from  ANA_TABLES_MACACCESS is
-	 * MACACCESS_CMD_IDLE, the issued command completed successfully.
-	 */
-	do {
-		val = ocelot_read(ocelot, ANA_TABLES_MACACCESS);
-		val &= ANA_TABLES_MACACCESS_MAC_TABLE_CMD_M;
-	} while (val != MACACCESS_CMD_IDLE && timeout--);
+	return ocelot_read(ocelot, ANA_TABLES_MACACCESS);
+}
 
-	if (!timeout)
-		return -ETIMEDOUT;
+static inline int ocelot_mact_wait_for_completion(struct ocelot *ocelot)
+{
+	u32 val;
 
-	return 0;
+	return readx_poll_timeout(ocelot_mact_read_macaccess,
+		ocelot, val,
+		(val & ANA_TABLES_MACACCESS_MAC_TABLE_CMD_M) ==
+		MACACCESS_CMD_IDLE,
+		TABLE_UPDATE_SLEEP_US, TABLE_UPDATE_TIMEOUT_US);
 }
 
 static void ocelot_mact_select(struct ocelot *ocelot,
@@ -129,23 +130,21 @@ static void ocelot_mact_init(struct ocelot *ocelot)
 	ocelot_write(ocelot, MACACCESS_CMD_INIT, ANA_TABLES_MACACCESS);
 }
 
-static inline int ocelot_vlant_wait_for_completion(struct ocelot *ocelot)
+static inline u32 ocelot_vlant_read_vlanaccess(struct ocelot *ocelot)
 {
-	unsigned int val, timeout = 10;
-
-	/* Wait for the issued vlan table command to be completed, or timeout.
-	 * When the command read from ANA_TABLES_VLANACCESS is
-	 * VLANACCESS_CMD_IDLE, the issued command completed successfully.
-	 */
-	do {
-		val = ocelot_read(ocelot, ANA_TABLES_VLANACCESS);
-		val &= ANA_TABLES_VLANACCESS_VLAN_TBL_CMD_M;
-	} while (val != ANA_TABLES_VLANACCESS_CMD_IDLE && timeout--);
+	return ocelot_read(ocelot, ANA_TABLES_VLANACCESS);
+}
 
-	if (!timeout)
-		return -ETIMEDOUT;
+static inline int ocelot_vlant_wait_for_completion(struct ocelot *ocelot)
+{
+	u32 val;
 
-	return 0;
+	return readx_poll_timeout(ocelot_vlant_read_vlanaccess,
+		ocelot,
+		val,
+		(val & ANA_TABLES_VLANACCESS_VLAN_TBL_CMD_M) ==
+		ANA_TABLES_VLANACCESS_CMD_IDLE,
+		TABLE_UPDATE_SLEEP_US, TABLE_UPDATE_TIMEOUT_US);
 }
 
 static int ocelot_vlant_set_mask(struct ocelot *ocelot, u16 vid, u32 mask)
-- 
2.20.1

Re: [PATCH net] mscc: Register poll timeout should be wall time not attempts

[Alexandre Belloni]

On 20/12/2018 10:08:16+0100, Steen Hegelund wrote:
> When doing indirect access in the Ocelot chip, a command is setup,
> issued and then we need to poll until the result is ready. The polling
> timeout is specified in milliseconds in the datasheet and not in
> register access attempts.
> 
> Signed-off-by: Steen Hegelund <steen.hegelund@microchip.com>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

> ---
>  drivers/net/ethernet/mscc/ocelot.c | 55 +++++++++++++++---------------
>  1 file changed, 27 insertions(+), 28 deletions(-)
> 
> diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c
> index 3238b9ee42f3..debe74e4a041 100644
> --- a/drivers/net/ethernet/mscc/ocelot.c
> +++ b/drivers/net/ethernet/mscc/ocelot.c
> @@ -15,6 +15,7 @@
>  #include <linux/netdevice.h>
>  #include <linux/phy.h>
>  #include <linux/skbuff.h>
> +#include <linux/iopoll.h>
>  #include <net/arp.h>
>  #include <net/netevent.h>
>  #include <net/rtnetlink.h>
> @@ -22,6 +23,9 @@
>  
>  #include "ocelot.h"
>  
> +#define TABLE_UPDATE_SLEEP_US 10
> +#define TABLE_UPDATE_TIMEOUT_US 100000
> +
>  /* MAC table entry types.
>   * ENTRYTYPE_NORMAL is subject to aging.
>   * ENTRYTYPE_LOCKED is not subject to aging.
> @@ -41,23 +45,20 @@ struct ocelot_mact_entry {
>  	enum macaccess_entry_type type;
>  };
>  
> -static inline int ocelot_mact_wait_for_completion(struct ocelot *ocelot)
> +static inline u32 ocelot_mact_read_macaccess(struct ocelot *ocelot)
>  {
> -	unsigned int val, timeout = 10;
> -
> -	/* Wait for the issued mac table command to be completed, or timeout.
> -	 * When the command read from  ANA_TABLES_MACACCESS is
> -	 * MACACCESS_CMD_IDLE, the issued command completed successfully.
> -	 */
> -	do {
> -		val = ocelot_read(ocelot, ANA_TABLES_MACACCESS);
> -		val &= ANA_TABLES_MACACCESS_MAC_TABLE_CMD_M;
> -	} while (val != MACACCESS_CMD_IDLE && timeout--);
> +	return ocelot_read(ocelot, ANA_TABLES_MACACCESS);
> +}
>  
> -	if (!timeout)
> -		return -ETIMEDOUT;
> +static inline int ocelot_mact_wait_for_completion(struct ocelot *ocelot)
> +{
> +	u32 val;
>  
> -	return 0;
> +	return readx_poll_timeout(ocelot_mact_read_macaccess,
> +		ocelot, val,
> +		(val & ANA_TABLES_MACACCESS_MAC_TABLE_CMD_M) ==
> +		MACACCESS_CMD_IDLE,
> +		TABLE_UPDATE_SLEEP_US, TABLE_UPDATE_TIMEOUT_US);
>  }
>  
>  static void ocelot_mact_select(struct ocelot *ocelot,
> @@ -129,23 +130,21 @@ static void ocelot_mact_init(struct ocelot *ocelot)
>  	ocelot_write(ocelot, MACACCESS_CMD_INIT, ANA_TABLES_MACACCESS);
>  }
>  
> -static inline int ocelot_vlant_wait_for_completion(struct ocelot *ocelot)
> +static inline u32 ocelot_vlant_read_vlanaccess(struct ocelot *ocelot)
>  {
> -	unsigned int val, timeout = 10;
> -
> -	/* Wait for the issued vlan table command to be completed, or timeout.
> -	 * When the command read from ANA_TABLES_VLANACCESS is
> -	 * VLANACCESS_CMD_IDLE, the issued command completed successfully.
> -	 */
> -	do {
> -		val = ocelot_read(ocelot, ANA_TABLES_VLANACCESS);
> -		val &= ANA_TABLES_VLANACCESS_VLAN_TBL_CMD_M;
> -	} while (val != ANA_TABLES_VLANACCESS_CMD_IDLE && timeout--);
> +	return ocelot_read(ocelot, ANA_TABLES_VLANACCESS);
> +}
>  
> -	if (!timeout)
> -		return -ETIMEDOUT;
> +static inline int ocelot_vlant_wait_for_completion(struct ocelot *ocelot)
> +{
> +	u32 val;
>  
> -	return 0;
> +	return readx_poll_timeout(ocelot_vlant_read_vlanaccess,
> +		ocelot,
> +		val,
> +		(val & ANA_TABLES_VLANACCESS_VLAN_TBL_CMD_M) ==
> +		ANA_TABLES_VLANACCESS_CMD_IDLE,
> +		TABLE_UPDATE_SLEEP_US, TABLE_UPDATE_TIMEOUT_US);
>  }
>  
>  static int ocelot_vlant_set_mask(struct ocelot *ocelot, u16 vid, u32 mask)
> -- 
> 2.20.1
> 

-- 
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

Re: [PATCH net] mscc: Register poll timeout should be wall time not attempts

[Andrew Lunn]

On Thu, Dec 20, 2018 at 10:08:16AM +0100, Steen Hegelund wrote:
> When doing indirect access in the Ocelot chip, a command is setup,
> issued and then we need to poll until the result is ready. The polling
> timeout is specified in milliseconds in the datasheet and not in
> register access attempts.
> 
> Signed-off-by: Steen Hegelund <steen.hegelund@microchip.com>

Hi Steen

Have you seen real issues with this code? You have marked this for
net, indicating it is a bug fix. If it is a real fix, please provide a
fixes: tag.

Thanks
	Andrew

Re: [PATCH net] mscc: Register poll timeout should be wall time not attempts

[Steen Hegelund]

The 12/20/2018 11:31, Andrew Lunn wrote:
> On Thu, Dec 20, 2018 at 10:08:16AM +0100, Steen Hegelund wrote:
> > When doing indirect access in the Ocelot chip, a command is setup,
> > issued and then we need to poll until the result is ready. The polling
> > timeout is specified in milliseconds in the datasheet and not in
> > register access attempts.
> > 
> > Signed-off-by: Steen Hegelund <steen.hegelund@microchip.com>
> 
> Hi Steen
> 
> Have you seen real issues with this code? You have marked this for
> net, indicating it is a bug fix. If it is a real fix, please provide a
> fixes: tag.
> 
> Thanks
> 	Andrew

Hi Andrew,

It is not a bug on the currently supported platform, but we observed
that the code does not work properly on other platforms that we want to
support as the timing requirements there are different.  So maybe this
is rather an improvement than a fix...

Should this rather go to net-next?

-- 
BR
Steen

Re: [PATCH net] mscc: Register poll timeout should be wall time not attempts

[Andrew Lunn]

On Thu, Dec 20, 2018 at 12:11:50PM +0100, Steen Hegelund wrote:
> The 12/20/2018 11:31, Andrew Lunn wrote:
> > On Thu, Dec 20, 2018 at 10:08:16AM +0100, Steen Hegelund wrote:
> > > When doing indirect access in the Ocelot chip, a command is setup,
> > > issued and then we need to poll until the result is ready. The polling
> > > timeout is specified in milliseconds in the datasheet and not in
> > > register access attempts.
> > > 
> > > Signed-off-by: Steen Hegelund <steen.hegelund@microchip.com>
> > 
> > Hi Steen
> > 
> > Have you seen real issues with this code? You have marked this for
> > net, indicating it is a bug fix. If it is a real fix, please provide a
> > fixes: tag.
> > 
> > Thanks
> > 	Andrew
> 
> Hi Andrew,
> 
> It is not a bug on the currently supported platform, but we observed
> that the code does not work properly on other platforms that we want to
> support as the timing requirements there are different.  So maybe this
> is rather an improvement than a fix...
> 
> Should this rather go to net-next?

The requirements for stable are listed here:

https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html

net-next seems a better fit.

	 Andrew