Re: [dpdk-dev] [PATCH v5 7/7] net/ark: Arkville PMD component integration

[Ed Czeck <ed.czeck@atomicrules.com>]

On Tue, Mar 28, 2017 at 10:38 AM, Ferruh Yigit <ferruh.yigit@intel.com>
wrote:

> On 3/23/2017 11:01 PM, Ed Czeck wrote:
> > * Flesh out device configuration
> > * Add links dev_ops
> > * allow dynamic extension loading
> >
> > Signed-off-by: Shepard Siegel <shepard.siegel@atomicrules.com>
> > Signed-off-by: John Miller <john.miller@atomicrules.com>
> > Signed-off-by: Ed Czeck <ed.czeck@atomicrules.com>
>
> <...>
>
> > +FW version           = Y
>
> FW version is not required, as far as I can see, it requires
> fw_version_get eth_dev_ops implemented.
>
Entry removed.


>
> <...>
>
> > +     /* We are a single function multi-port device. */
> > +     const unsigned int numa_node = rte_socket_id();
> > +     struct ether_addr adr;
> > +
> > +     ret = ark_config_device(dev);
> >       dev->dev_ops = &ark_eth_dev_ops;
> >
> > +     dev->data->mac_addrs = rte_zmalloc("ark", ETHER_ADDR_LEN, 0);
> > +     if (!dev->data->mac_addrs) {
> > +             PMD_DRV_LOG(ERR,
> > +                         "Failed to allocated memory for storing mac
> address"
> > +                         );
> > +     }
> > +     ether_addr_copy((struct ether_addr *)&adr,
> &dev->data->mac_addrs[0]);
>
> "adr" has random value at this point, right? Why to copy it?
>
Code removed.   The mac address is left as 0, since arkville does not
include a mac.


> > +     int pc = 1;
> > +     int p;
>
> I am aware some people prefer the declaring variables close to context,
> which is good idea, but if I remember correct, there was a patchset,
> from Adrien, to make DPDK C99 compatible, will this break it?
>
I moved the declarations to the top of the function to match the dpdk style.



> > +
> > +     if (ark->user_ext.dev_get_port_count) {
> > +             pc = ark->user_ext.dev_get_port_count(dev,
> ark->user_data);
> > +             ark->num_ports = pc;
> > +     } else {
> > +             ark->num_ports = 1;
>
> Because pc has default value of "1", this if statement can be simplified.
>
Code has been simplified to 3 lines.


>
> > +     }
> > +     for (p = 0; p < pc; p++) {
> > +             struct ark_port *port;
> > +
> > +             port = &ark->port[p];
> > +             struct rte_eth_dev_data *data = NULL;
> > +
> > +             port->id = p;
> > +
> > +             char name[RTE_ETH_NAME_MAX_LEN];
> > +
> > +             snprintf(name, sizeof(name), "arketh%d",
> > +                      dev->data->port_id + p);
> > +
> > +             if (p == 0) {
> > +                     /* First port is already allocated by DPDK */
> > +                     port->eth_dev = ark->eth_dev;
> > +                     continue;
> > +             }
> > +
> > +             /* reserve an ethdev entry */
> > +             port->eth_dev = rte_eth_dev_allocate(name);
> > +             if (!port->eth_dev) {
> > +                     PMD_DRV_LOG(ERR,
> > +                                 "Could not allocate eth_dev for port
> %d\n",
> > +                                 p);
> > +                     goto error;
> > +             }
> > +
> > +             data = rte_zmalloc_socket(name, sizeof(*data), 0,
> numa_node);
> > +             if (!data) {
> > +                     PMD_DRV_LOG(ERR,
> > +                                 "Could not allocate eth_dev for port
> %d\n",
> > +                                 p);
> > +                     goto error;
> > +             }
> > +             data->port_id = ark->eth_dev->data->port_id + p;
>
> "ark->eth_dev->data->port_id" is port_id of the first physical ARK
> device, and it looks like each device may have multiple ports and "p" is
> the port_id within same device.
>
Arkville is a single PCIE function with 1 or more ports, lets call this p.
After initialization each there will be p additional devices, and each
device will have exactly 1 port.
We now understand the features of the rte_eth_dev_allocate(), and have
simplified this code avoid the unnecessary copies.


>
> From DPDK point of view, port_id is a global value incremented one by
> each eth port, so port_id is a unique value, why adding these two values?
>
> > +             port->eth_dev->data = data;
>
> Why overwriting existing data value?
>
> > +             port->eth_dev->device = &pci_dev->device;
> > +
>
> > +                             ark->user_ext.dev_init(dev, ark->a_bar, p);
> > +     }
>
Unnecessary coping has been removed.




>
> <...>
>
> >  static int
> >  eth_ark_dev_uninit(struct rte_eth_dev *dev)
> >  {
>
>
> Shouldn't uninit go thorough all ports ("for (p = 0; p < pc; p++) ") and
> uninit them all?
>
 Arkville has one PCIE function, during initialization we  determine the
number of ports, and from that one device for each port will be created.
At the end, there will be p devices, each with one port.   So during device
uninit, there is only 1 port.


>
>
> <...>
>
> > +/*
> > + * The following functions are optional and are directly mapped
> > + * from the DPDK PMD ops structure.
> > + * Each function if implemented is called after the ARK PMD
> > + * implementation executes.
> > + */
> > +int dev_configure(struct rte_eth_dev *dev, void *user_data);
> > +int dev_start(struct rte_eth_dev *dev, void *user_data);
> > +void dev_stop(struct rte_eth_dev *dev, void *user_data);
> > +void dev_close(struct rte_eth_dev *dev, void *user_data);
> > +int link_update(struct rte_eth_dev *dev, int wait_to_complete,
> > +     void *user_data);
> > +int dev_set_link_up(struct rte_eth_dev *dev, void *user_data);
> > +int dev_set_link_down(struct rte_eth_dev *dev, void *user_data);
> > +void stats_get(struct rte_eth_dev *dev, struct rte_eth_stats *stats,
> > +     void *user_data);
> > +void stats_reset(struct rte_eth_dev *dev, void *user_data);
> > +void mac_addr_add(struct rte_eth_dev *dev,
> > +     struct ether_addr *macadr,
> > +                               uint32_t index,
> > +                               uint32_t pool,
> > +                               void *user_data);
> > +void mac_addr_remove(struct rte_eth_dev *dev, uint32_t index, void
> *user_data);
> > +void mac_addr_set(struct rte_eth_dev *dev, struct ether_addr *mac_addr,
> > +     void *user_data);
>
> Where these functions are implemented? Do we need these declarations?
>
The following comment has been added to this file, which addresses your
question.
/*
 * This is the template file for users who which to define a dynamic
 * extension to the Arkville PMD.   User's who create an extension
 * should include this file and define the necessary and desired
 * functions.
 * Only 1 function is required for an extension, dev_init(); all other
 * functions prototyped in this file are optional.
 */

Thanks
Ed.