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

[Panu Matilainen <pmatilai@redhat.com>]

On 05/25/2016 09:36 AM, 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>
> ---
>  lib/librte_ether/rte_ethdev.c | 12 ++++++++++++
>  lib/librte_ether/rte_ethdev.h | 18 ++++++++++++++++++
>  2 files changed, 30 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;

This is an ABI break, but maybe it is part of that "driver 
implementation API" which is exempt from the ABI/API policies. Thomas?

> @@ -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
>   *

The function needs to be exported via rte_ether_version.map as well.

	- Panu -
>