[1/4] common/sfc_efx/base: NIC Partitioning mode discovery using heuristic approach

  NIC Partitioning mode in SFN devices means multiple PFs per network port.
When NIC Partitioning is configured, apart from the privileged adapter(s) the
other unprivileged adapter(s) will share the same physical port.
Determining NIC Partitioning mode is required to take necessary action(s) for
unprivileged adapter to work seamlessly.
NIC Partitioning is determined using heuristic approach - If the physical ports
are shared between PFs then either NIC Partitioning or SR-IOV is in use.
When NIC Partitioning is in use MAX MTU workaround should be applied so that
the unprivileged functions can seamlessly configure any valid MTU.

hg-changeset: 7f0abee725a8e9c6524e773e5e5d6286a3b027a4

Signed-off-by: Sandilya Bhagi <sbhagi@solarflare.com>
Signed-off-by: Denis Pryazhennikov <denis.pryazhennikov@arknetworks.am>
Reviewed-by: Andy Moreton <amoreton@xilinx.com>
---
 drivers/common/sfc_efx/base/ef10_nic.c | 109 +++++++++++++++++++++++++
 drivers/common/sfc_efx/base/efx.h      |   8 ++
 2 files changed, 117 insertions(+)
  

Summary must not be a statement. Also summary is too long.

On 6/1/23 14:42, Denis Pryazhennikov wrote:
> NIC Partitioning mode in SFN devices means multiple PFs per network port.
> When NIC Partitioning is configured, apart from the privileged adapter(s) the
> other unprivileged adapter(s) will share the same physical port.
> Determining NIC Partitioning mode is required to take necessary action(s) for
> unprivileged adapter to work seamlessly.
> NIC Partitioning is determined using heuristic approach - If the physical ports
> are shared between PFs then either NIC Partitioning or SR-IOV is in use.
> When NIC Partitioning is in use MAX MTU workaround should be applied so that
> the unprivileged functions can seamlessly configure any valid MTU.
> 
> hg-changeset: 7f0abee725a8e9c6524e773e5e5d6286a3b027a4

I'm not sure that it is appropriate here.

> 
> Signed-off-by: Sandilya Bhagi <sbhagi@solarflare.com>

I'd like to understand how is the first author of the patch.
I guess the first signed-off-by. If so, it should be in From
as well.

> Signed-off-by: Denis Pryazhennikov <denis.pryazhennikov@arknetworks.am>
> Reviewed-by: Andy Moreton <amoreton@xilinx.com>
> ---
>   drivers/common/sfc_efx/base/ef10_nic.c | 109 +++++++++++++++++++++++++
>   drivers/common/sfc_efx/base/efx.h      |   8 ++
>   2 files changed, 117 insertions(+)
> 
> diff --git a/drivers/common/sfc_efx/base/ef10_nic.c b/drivers/common/sfc_efx/base/ef10_nic.c
> index e1709d120093..db4834a65175 100644
> --- a/drivers/common/sfc_efx/base/ef10_nic.c
> +++ b/drivers/common/sfc_efx/base/ef10_nic.c
> @@ -1044,6 +1044,89 @@ ef10_mcdi_get_pf_count(
>   	return (rc);
>   }
>   
> +static	__checkReturn	efx_rc_t
> +ef10_nic_get_physical_port_usage(
> +	__in		efx_nic_t *enp,
> +	__in_ecount(pfs_to_ports_size)	uint8_t *pfs_to_ports,
> +	__in		size_t pfs_to_ports_size,
> +	__out		efx_port_usage_t *port_usagep)
> +{
> +	efx_nic_cfg_t *encp = &(enp->en_nic_cfg);
> +	efx_port_usage_t port_usage;
> +	size_t pf;
> +	uint8_t phy_port;
> +	efx_rc_t rc;
> +
> +	/*
> +	 * The sharing of physical ports between functions are determined
> +	 * in the following way.
> +	 * 1. If VFs are enabled then the physical port is shared.
> +	 * 2. Retrieve PFs to ports assignment.
> +	 * 3. If PF 0 assignment cannot be retrieved(ACCESS_DENIED), it
> +	 *    implies this is an unprivileged function. An unprivileged
> +	 *    function indicates the physical port must be shared with
> +	 *    another privileged function.
> +	 * 4. If PF 0 assignment can be retrieved, it indicates this
> +	 *    function is privileged. Now, read all other PF's physical
> +	 *    port number assignment and check if the current PF's physical
> +	 *    port is shared with any other PF's physical port.
> +	 * NOTE: Sharing of physical ports (using heuristic approach) can
> +	 * imply either NIC Partitioning or SR-IOV is in use. This info is
> +	 * sufficient to apply the max MTU workaround (WIN-628), but should
> +	 * not be used for other purposes.

I guess you're going to use it for other purpose.

> +	 * NOTE: PF 0 is always privileged function.
> +	 */
> +
> +	if (EFX_PCI_FUNCTION_IS_VF(encp)) {
> +		port_usage = EFX_PORT_USAGE_SHARED;
> +		goto out;
> +	}
> +
> +	if (pfs_to_ports[0] ==
> +	            MC_CMD_GET_CAPABILITIES_V2_OUT_ACCESS_NOT_PERMITTED) {
> +		/*
> +		 * This is unprivileged function as it do not have sufficient
> +		 * privileges to read the value, this implies the physical port
> +		 * is shared between this function and another privileged
> +		 * function
> +		 */
> +		port_usage = EFX_PORT_USAGE_SHARED;
> +		goto out;
> +	}
> +
> +	if (encp->enc_pf >= pfs_to_ports_size) {
> +		rc = EINVAL;
> +		goto fail1;
> +	}
> +	phy_port = pfs_to_ports[encp->enc_pf];
> +
> +	/*
> +	 * This is privileged function as it is able read the value of
> +	 * PF 0. Now, check if any other function share the same physical
> +	 * port number as this function.
> +	 */
> +	for (pf = 0; pf < pfs_to_ports_size; pf++) {
> +
> +		if ((encp->enc_pf != pf) &&
> +		    (phy_port == pfs_to_ports[pf])) {
> +			/* Found match, PFs share the same physical port */
> +			port_usage = EFX_PORT_USAGE_SHARED;
> +			goto out;
> +		}
> +	}
> +
> +	port_usage = EFX_PORT_USAGE_EXCLUSIVE;
> +
> +out:
> +	*port_usagep = port_usage;
> +	return (0);
> +
> +fail1:
> +	EFSYS_PROBE1(fail1, efx_rc_t, rc);
> +
> +	return (rc);
> +}
> +
>   static	__checkReturn	efx_rc_t
>   ef10_get_datapath_caps(
>   	__in		efx_nic_t *enp)
> @@ -1307,6 +1390,32 @@ ef10_get_datapath_caps(
>   		encp->enc_tunnel_config_udp_entries_max = 0;
>   	}
>   
> +#define CAP_PFS_TO_PORTS(_n)						\
> +	(MC_CMD_GET_CAPABILITIES_V2_OUT_PFS_TO_PORTS_ASSIGNMENT_ ## _n)
> +
> +	encp->enc_port_usage = EFX_PORT_USAGE_UNKNOWN;
> +
> +	if (req.emr_out_length_used >= MC_CMD_GET_CAPABILITIES_V2_OUT_LEN) {
> +		/* PFs to ports assignment */
> +		uint8_t pfs_to_ports[CAP_PFS_TO_PORTS(NUM)];
> +		efx_byte_t *bytep;
> +		int i;
> +
> +		bytep = MCDI_OUT(req, efx_byte_t, CAP_PFS_TO_PORTS(OFST));
> +		for (i = 0; i < EFX_ARRAY_SIZE(pfs_to_ports); i++) {
> +			pfs_to_ports[i] = EFX_BYTE_FIELD(*bytep, EFX_BYTE_0);
> +			bytep += CAP_PFS_TO_PORTS(LEN);
> +		}

Sorry, but it looks like memcpy() byte-by-byte.

> +
> +		if (ef10_nic_get_physical_port_usage(enp,
> +		    pfs_to_ports, EFX_ARRAY_SIZE(pfs_to_ports),
> +		    &encp->enc_port_usage) != 0) {

Alignment is misleading above and hard to read. Either correct
an alignment or simply call the function before if.

> +			/* PF to port mapping lookup failed */
> +			encp->enc_port_usage = EFX_PORT_USAGE_UNKNOWN;
> +		}
> +	}
> +#undef  CAP_PFS_TO_PORTS
> +
>   	/*
>   	 * Check if firmware reports the VI window mode.
>   	 * Medford2 has a variable VI window size (8K, 16K or 64K).
> diff --git a/drivers/common/sfc_efx/base/efx.h b/drivers/common/sfc_efx/base/efx.h
> index 49e29dcc1c69..93bb4916bfd6 100644
> --- a/drivers/common/sfc_efx/base/efx.h
> +++ b/drivers/common/sfc_efx/base/efx.h
> @@ -311,6 +311,12 @@ efx_nic_check_pcie_link_speed(
>   	__in		uint32_t pcie_link_gen,
>   	__out		efx_pcie_link_performance_t *resultp);
>   
> +typedef enum efx_port_usage_e {
> +	EFX_PORT_USAGE_UNKNOWN = 0,
> +	EFX_PORT_USAGE_EXCLUSIVE,	/* Port only used by this PF */
> +	EFX_PORT_USAGE_SHARED,		/* Port shared with other PFs */
> +} efx_port_usage_t;
> +
>   #define	EFX_MAC_ADDR_LEN 6
>   
>   #if EFSYS_OPT_MCDI
> @@ -1680,6 +1686,8 @@ typedef struct efx_nic_cfg_s {
>   	uint32_t		enc_assigned_port;
>   	/* NIC DMA mapping type */
>   	efx_nic_dma_mapping_t	enc_dma_mapping;
> +	/* Physical ports shared by PFs */
> +	efx_port_usage_t	enc_port_usage;
>   } efx_nic_cfg_t;
>   
>   #define	EFX_PCI_VF_INVALID 0xffff