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

[Alexandre Belloni <alexandre.belloni@bootlin.com>]

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