RE: [PATCH v2 2/9] NTB: Add indexed ports NTB API

From: Allen Hubbe
Date: Mon Dec 12 2016 - 23:12:32 EST

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From: Serge Semin
> There are some NTB hardware, which can combine more than just two domains
> over NTB. For instance, some IDT PCIe-switches can have NTB-functions
> activated on more than two-ports. The different domains are distinguished
> by ports they are connected to. So the new port-related methods are added to
> the NTB API:
> ntb_port_number() - return local port
> ntb_peer_port_count() - return number of peers local port can connect to
> ntb_peer_port_number(pdix) - return port number by it index
> ntb_peer_port_idx(port) - return port index by it number
>
> Current test-drivers aren't changed much. They still support two-ports devices
> for the time being while multi-ports hardware drivers aren't added.
>

The port methods are the same for PRI/SEC drivers. Rather than duplicating the code, multiport could be made optional in the api, and default implementations provided by ntb common code.

Some comments below.

> Signed-off-by: Serge Semin <fancer.lancer@xxxxxxxxx>
>
> ---
> drivers/ntb/hw/amd/ntb_hw_amd.c | 47 ++++++++++++++++++++++++
> drivers/ntb/hw/amd/ntb_hw_amd.h | 9 +++++
> drivers/ntb/hw/intel/ntb_hw_intel.c | 52 ++++++++++++++++++++++++++-
> drivers/ntb/hw/intel/ntb_hw_intel.h | 9 +++++
> drivers/ntb/ntb_transport.c | 6 ++++
> drivers/ntb/test/ntb_perf.c | 4 +++
> drivers/ntb/test/ntb_pingpong.c | 6 ++++
> drivers/ntb/test/ntb_tool.c | 5 +++
> include/linux/ntb.h | 71 +++++++++++++++++++++++++++++++++++++
> 9 files changed, 208 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/ntb/hw/amd/ntb_hw_amd.c b/drivers/ntb/hw/amd/ntb_hw_amd.c
> index 6704327..0b767ef 100644
> --- a/drivers/ntb/hw/amd/ntb_hw_amd.c
> +++ b/drivers/ntb/hw/amd/ntb_hw_amd.c
> @@ -71,6 +71,49 @@ MODULE_AUTHOR("AMD Inc.");
> static const struct file_operations amd_ntb_debugfs_info;
> static struct dentry *debugfs_dir;
>
> +static int amd_ntb_port_number(struct ntb_dev *ntb)
> +{
> + switch (ntb->topo) {
> + case NTB_TOPO_PRI:
> + case NTB_TOPO_B2B_USD:
> + return NTB_PORT_PRI_USD;
> + case NTB_TOPO_SEC:
> + case NTB_TOPO_B2B_DSD:
> + return NTB_PORT_SEC_DSD;
> + default:
> + break;
> + }
> +
> + return -EINVAL;
> +}
> +
> +static int amd_ntb_peer_port_count(struct ntb_dev *ntb)
> +{
> + return NTB_PEER_CNT;
> +}
> +
> +static int amd_ntb_peer_port_number(struct ntb_dev *ntb, int pidx)
> +{
> + int local_port = amd_ntb_port_number(ntb);
> +
> + if (pidx > NTB_PIDX_MAX)
> + return -EINVAL;

pidx may be negative.

> +
> + return (local_port == NTB_PORT_PRI_USD ?
> + NTB_PORT_SEC_DSD : NTB_PORT_PRI_USD);

local_port may be -EINVAL.

It may be simpler to have the same switch statement here as in amd_ntb_port_number(), with the return statements swapped.

> +}
> +
> +static int amd_ntb_peer_port_idx(struct ntb_dev *ntb, int port)
> +{
> + int local_port = amd_ntb_port_number(ntb);
> +
> + if ((local_port == NTB_PORT_PRI_USD && port != NTB_PORT_SEC_DSD) ||
> + (local_port == NTB_PORT_SEC_DSD && port != NTB_PORT_PRI_USD))
> + return -EINVAL;
> +

How about:

peer_port = amd_ntb_peer_port_number(ntb, 0);

if (peer_port == -EINVAL || port != peer_port)
return -EINVAL;

return 0;

> + return 0;
> +}
> +
> static int amd_link_is_up(struct amd_ntb_dev *ndev)
> {
> if (!ndev->peer_sta)
> @@ -431,6 +474,10 @@ static int amd_ntb_peer_spad_write(struct ntb_dev *ntb,
> }
>
> static const struct ntb_dev_ops amd_ntb_ops = {
> + .port_number = amd_ntb_port_number,
> + .peer_port_count = amd_ntb_peer_port_count,
> + .peer_port_number = amd_ntb_peer_port_number,
> + .peer_port_idx = amd_ntb_peer_port_idx,
> .link_is_up = amd_ntb_link_is_up,
> .link_enable = amd_ntb_link_enable,
> .link_disable = amd_ntb_link_disable,
> diff --git a/drivers/ntb/hw/amd/ntb_hw_amd.h b/drivers/ntb/hw/amd/ntb_hw_amd.h
> index 2eac3cd..1aeb08f 100644
> --- a/drivers/ntb/hw/amd/ntb_hw_amd.h
> +++ b/drivers/ntb/hw/amd/ntb_hw_amd.h
> @@ -62,6 +62,10 @@
> #define NTB_LNK_STA_SPEED(x) (((x) & NTB_LNK_STA_SPEED_MASK) >> 16)
> #define NTB_LNK_STA_WIDTH(x) (((x) & NTB_LNK_STA_WIDTH_MASK) >> 20)
>
> +/* port related constants */
> +#define NTB_PEER_CNT (1)
> +#define NTB_PIDX_MAX (0)

Just NTB_PEER_CNT is sufficient. Anything that checks if (pidx > NTB_PIDX_MAX) could check if (pidx >= NTB_PEER_CNT).

> +
> #ifndef read64
> #ifdef readq
> #define read64 readq
> @@ -91,6 +95,11 @@ static inline void _write64(u64 val, void __iomem *mmio)
> #endif
> #endif
>
> +enum amd_ntb_port {
> + NTB_PORT_PRI_USD,
> + NTB_PORT_SEC_DSD
> +};

This could be part of ntb.h, since it will likely be the same for any of the PRI/SEC variety of NTB devices. Making it a part of the api will encourage other PRI/SEC drivers to assign port numbers the same way using these values. Or, drivers may be made consistent by sharing common code.

> +
> enum {
> /* AMD NTB Capability */
> AMD_MW_CNT = 3,
> diff --git a/drivers/ntb/hw/intel/ntb_hw_intel.c b/drivers/ntb/hw/intel/ntb_hw_intel.c
> index 68d9908..7e44dc3 100644
> --- a/drivers/ntb/hw/intel/ntb_hw_intel.c
> +++ b/drivers/ntb/hw/intel/ntb_hw_intel.c
> @@ -1035,6 +1035,49 @@ static void ndev_deinit_debugfs(struct intel_ntb_dev *ndev)
> debugfs_remove_recursive(ndev->debugfs_dir);
> }

Apply same comments above to Intel driver.

>
> +static int intel_ntb_port_number(struct ntb_dev *ntb)
> +{
> + switch (ntb->topo) {
> + case NTB_TOPO_PRI:
> + case NTB_TOPO_B2B_USD:
> + return NTB_PORT_PRI_USD;
> + case NTB_TOPO_SEC:
> + case NTB_TOPO_B2B_DSD:
> + return NTB_PORT_SEC_DSD;
> + default:
> + break;
> + }
> +
> + return -EINVAL;
> +}
> +
> +static int intel_ntb_peer_port_count(struct ntb_dev *ntb)
> +{
> + return NTB_PEER_CNT;
> +}
> +
> +static int intel_ntb_peer_port_number(struct ntb_dev *ntb, int pidx)
> +{
> + int local_port = intel_ntb_port_number(ntb);
> +
> + if (pidx > NTB_PIDX_MAX)
> + return -EINVAL;
> +
> + return (local_port == NTB_PORT_PRI_USD ?
> + NTB_PORT_SEC_DSD : NTB_PORT_PRI_USD);
> +}
> +
> +static int intel_ntb_peer_port_idx(struct ntb_dev *ntb, int port)
> +{
> + int local_port = intel_ntb_port_number(ntb);
> +
> + if ((local_port == NTB_PORT_PRI_USD && port != NTB_PORT_SEC_DSD) ||
> + (local_port == NTB_PORT_SEC_DSD && port != NTB_PORT_PRI_USD))
> + return -EINVAL;
> +
> + return 0;
> +}
> +
> static int intel_ntb_link_is_up(struct ntb_dev *ntb,
> enum ntb_speed *speed,
> enum ntb_width *width)
> @@ -1775,7 +1818,6 @@ static int skx_init_ntb(struct intel_ntb_dev *ndev)
> {
> int rc;
>
> -
> ndev->mw_count = XEON_MW_COUNT;
> ndev->spad_count = SKX_SPAD_COUNT;
> ndev->db_count = SKX_DB_COUNT;
> @@ -2883,6 +2925,10 @@ static const struct intel_ntb_xlat_reg skx_sec_xlat = {
>
> /* operations for primary side of local ntb */
> static const struct ntb_dev_ops intel_ntb_ops = {
> + .port_number = intel_ntb_port_number,
> + .peer_port_count = intel_ntb_peer_port_count,
> + .peer_port_number = intel_ntb_peer_port_number,
> + .peer_port_idx = intel_ntb_peer_port_idx,
> .link_is_up = intel_ntb_link_is_up,
> .link_enable = intel_ntb_link_enable,
> .link_disable = intel_ntb_link_disable,
> @@ -2909,6 +2955,10 @@ static const struct ntb_dev_ops intel_ntb_ops = {
> };
>
> static const struct ntb_dev_ops intel_ntb3_ops = {
> + .port_number = intel_ntb_port_number,
> + .peer_port_count = intel_ntb_peer_port_count,
> + .peer_port_number = intel_ntb_peer_port_number,
> + .peer_port_idx = intel_ntb_peer_port_idx,
> .link_is_up = intel_ntb_link_is_up,
> .link_enable = intel_ntb3_link_enable,
> .link_disable = intel_ntb_link_disable,
> diff --git a/drivers/ntb/hw/intel/ntb_hw_intel.h b/drivers/ntb/hw/intel/ntb_hw_intel.h
> index 6e8c182..f12c960 100644
> --- a/drivers/ntb/hw/intel/ntb_hw_intel.h
> +++ b/drivers/ntb/hw/intel/ntb_hw_intel.h
> @@ -295,6 +295,15 @@
> #define NTB_BAR_MASK_64 ~(0xfull)
> #define NTB_BAR_MASK_32 ~(0xfu)
>
> +/* port related constants */
> +#define NTB_PEER_CNT (1)
> +#define NTB_PIDX_MAX (0)
> +
> +enum intel_ntb_port {
> + NTB_PORT_PRI_USD,
> + NTB_PORT_SEC_DSD
> +};
> +
> struct intel_ntb_dev;
>
> struct intel_ntb_reg {
> diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
> index 4eb8adb..37d428d 100644
> --- a/drivers/ntb/ntb_transport.c
> +++ b/drivers/ntb/ntb_transport.c
> @@ -94,6 +94,9 @@ MODULE_PARM_DESC(use_dma, "Use DMA engine to perform large data copy");
>
> static struct dentry *nt_debugfs_dir;
>
> +/* Only two-ports NTB devices are supported */
> +#define PIDX 0
> +
> struct ntb_queue_entry {
> /* ntb_queue list reference */
> struct list_head entry;
> @@ -1083,6 +1086,9 @@ static int ntb_transport_probe(struct ntb_client *self, struct
> ntb_dev *ndev)
> dev_dbg(&ndev->dev,
> "scratchpad is unsafe, proceed anyway...\n");
>
> + if (ntb_peer_port_count(ndev) != 1)
> + dev_warn(&ndev->dev, "Multi-port NTB devices unsupported\n");
> +
> node = dev_to_node(&ndev->dev);
>
> nt = kzalloc_node(sizeof(*nt), GFP_KERNEL, node);
> diff --git a/drivers/ntb/test/ntb_perf.c b/drivers/ntb/test/ntb_perf.c
> index e75d4fd..481827a 100644
> --- a/drivers/ntb/test/ntb_perf.c
> +++ b/drivers/ntb/test/ntb_perf.c
> @@ -76,6 +76,7 @@
> #define DMA_RETRIES 20
> #define SZ_4G (1ULL << 32)
> #define MAX_SEG_ORDER 20 /* no larger than 1M for kmalloc buffer */
> +#define PIDX 0
>
> MODULE_LICENSE(DRIVER_LICENSE);
> MODULE_VERSION(DRIVER_VERSION);
> @@ -764,6 +765,9 @@ static int perf_probe(struct ntb_client *client, struct ntb_dev *ntb)
> return -EIO;
> }
>
> + if (ntb_peer_port_count(ntb) != 1)
> + dev_warn(&ntb->dev, "Multi-port NTB devices unsupported\n");
> +
> node = dev_to_node(&pdev->dev);
>
> perf = kzalloc_node(sizeof(*perf), GFP_KERNEL, node);
> diff --git a/drivers/ntb/test/ntb_pingpong.c b/drivers/ntb/test/ntb_pingpong.c
> index 4358611..6dd7582 100644
> --- a/drivers/ntb/test/ntb_pingpong.c
> +++ b/drivers/ntb/test/ntb_pingpong.c
> @@ -90,6 +90,9 @@ static unsigned long db_init = 0x7;
> module_param(db_init, ulong, 0644);
> MODULE_PARM_DESC(db_init, "Initial doorbell bits to ring on the peer");
>
> +/* Only two-ports NTB devices are supported */
> +#define PIDX 0
> +
> struct pp_ctx {
> struct ntb_dev *ntb;
> u64 db_bits;
> @@ -230,6 +233,9 @@ static int pp_probe(struct ntb_client *client,
> }
> }
>
> + if (ntb_peer_port_count(ntb) != 1)
> + dev_warn(&ntb->dev, "multi-port NTB is unsupported\n");
> +
> pp = kmalloc(sizeof(*pp), GFP_KERNEL);
> if (!pp) {
> rc = -ENOMEM;
> diff --git a/drivers/ntb/test/ntb_tool.c b/drivers/ntb/test/ntb_tool.c
> index 61bf2ef..85b6417 100644
> --- a/drivers/ntb/test/ntb_tool.c
> +++ b/drivers/ntb/test/ntb_tool.c
> @@ -120,6 +120,8 @@ MODULE_AUTHOR(DRIVER_AUTHOR);
> MODULE_DESCRIPTION(DRIVER_DESCRIPTION);
>
> #define MAX_MWS 16
> +/* Only two-ports devices are supported */
> +#define PIDX 0
>
> static struct dentry *tool_dbgfs;
>
> @@ -919,6 +921,9 @@ static int tool_probe(struct ntb_client *self, struct ntb_dev *ntb)
> if (ntb_spad_is_unsafe(ntb))
> dev_dbg(&ntb->dev, "scratchpad is unsafe\n");
>
> + if (ntb_peer_port_count(ntb) != 1)
> + dev_warn(&ntb->dev, "multi-port NTB is unsupported\n");
> +
> tc = kzalloc(sizeof(*tc), GFP_KERNEL);
> if (!tc) {
> rc = -ENOMEM;
> diff --git a/include/linux/ntb.h b/include/linux/ntb.h
> index 5d1f260..3216689 100644
> --- a/include/linux/ntb.h
> +++ b/include/linux/ntb.h
> @@ -179,6 +179,10 @@ static inline int ntb_ctx_ops_is_valid(const struct ntb_ctx_ops *ops)
>
> /**
> * struct ntb_ctx_ops - ntb device operations
> + * @port_number: See ntb_port_number().
> + * @peer_port_count: See ntb_peer_port_count().
> + * @peer_port_number: See ntb_peer_port_number().
> + * @peer_port_idx: See ntb_peer_port_idx().
> * @link_is_up: See ntb_link_is_up().
> * @link_enable: See ntb_link_enable().
> * @link_disable: See ntb_link_disable().
> @@ -212,6 +216,11 @@ static inline int ntb_ctx_ops_is_valid(const struct ntb_ctx_ops *ops)
> * @peer_spad_write: See ntb_peer_spad_write().
> */
> struct ntb_dev_ops {
> + int (*port_number)(struct ntb_dev *ntb);
> + int (*peer_port_count)(struct ntb_dev *ntb);
> + int (*peer_port_number)(struct ntb_dev *ntb, int pidx);
> + int (*peer_port_idx)(struct ntb_dev *ntb, int port);
> +
> int (*link_is_up)(struct ntb_dev *ntb,
> enum ntb_speed *speed, enum ntb_width *width);
> int (*link_enable)(struct ntb_dev *ntb,
> @@ -265,6 +274,10 @@ static inline int ntb_dev_ops_is_valid(const struct ntb_dev_ops *ops)
> {
> /* commented callbacks are not required: */
> return
> + ops->port_number &&
> + ops->peer_port_count &&
> + ops->peer_port_number &&
> + ops->peer_port_idx &&

If these are made optional, then:

!ops->peer_port_count == !ops->port_number &&
!ops->peer_port_number == !ops->port_number &&
!ops->peer_port_idx == !ops->port_number &&

> ops->link_is_up &&
> ops->link_enable &&
> ops->link_disable &&
> @@ -442,6 +455,64 @@ void ntb_link_event(struct ntb_dev *ntb);
> void ntb_db_event(struct ntb_dev *ntb, int vector);
>
> /**
> + * ntb_port_number() - get the local port number
> + * @ntb: NTB device context.
> + *
> + * Hardware must support at least simple two-ports ntb connection
> + *
> + * Return: the local port number
> + */
> +static inline int ntb_port_number(struct ntb_dev *ntb)
> +{

If these are made optional, then:

if (!ntb->ops->port_number)
return ntb_default_port_number(ntb);

> + return ntb->ops->port_number(ntb);
> +}
> +
> +/**
> + * ntb_peer_port_count() - get the number of peer device ports
> + * @ntb: NTB device context.
> + *
> + * Hardware may support an access to memory of several remote domains
> + * over multi-port NTB devices. This method returns the number of peers,
> + * local device can have shared memory with.
> + *
> + * Return: the number of peer ports
> + */
> +static inline int ntb_peer_port_count(struct ntb_dev *ntb)
> +{
> + return ntb->ops->peer_port_count(ntb);
> +}
> +
> +/**
> + * ntb_peer_port_number() - get the peer port by given index
> + * @ntb: NTB device context.
> + * @pidx: Peer port index.
> + *
> + * Peer ports are continuously enumerated by NTB API logic, so this methods
> + * lets to retrieve port real number by its index.
> + *
> + * Return: the peer device port or negative value indicating an error
> + */
> +static inline int ntb_peer_port_number(struct ntb_dev *ntb, int pidx)
> +{
> + return ntb->ops->peer_port_number(ntb, pidx);
> +}
> +
> +/**
> + * ntb_peer_port_idx() - get the peer device port index by given port number
> + * @ntb: NTB device context.
> + * @port: Peer port number.
> + *
> + * Inverse operation of ntb_peer_port_number(), so one can get port index
> + * by specified port number.
> + *
> + * Return: the peer port index or negative value indicating an error
> + */
> +static inline int ntb_peer_port_idx(struct ntb_dev *ntb, int port)
> +{
> + return ntb->ops->peer_port_idx(ntb, port);
> +}
> +
> +/**
> * ntb_link_is_up() - get the current ntb link state
> * @ntb: NTB device context.
> * @speed: OUT - The link speed expressed as PCIe generation number.
> --
> 2.6.6

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