[dpdk-dev] [PATCH 1/4] pci: allow access to PCI config space

David Marchand david.marchand at 6wind.com
Mon Feb 9 10:45:01 CET 2015


Hello Stephen,

- It looks a bit odd to me, we end up with something asymetric between uio
/ vfio wrt pci config space.
Can we an api consistent between the two ?
Does this mean that your pmd cannot work / has not been used with vfio ?

- Anyway, I suppose we could reuse this api to remove the RTE_PCI_CONFIG
#ifdef / hardcoded stuff from linux eal / igb_uio.
Opinion ?


-- 
David Marchand


On Fri, Feb 6, 2015 at 7:36 PM, Stephen Hemminger <
stephen at networkplumber.org> wrote:

> From: Stephen Hemminger <shemming at brocade.com>
>
> Some drivers need ability to access PCI config (for example for power
> management). This adds an abstraction to do this; only implemented
> on Linux, but should be possible on BSD.
>
> Signed-off-by: Stephen Hemminger <stephen at networkplumber.org>
> ---
>  lib/librte_eal/common/include/rte_pci.h         | 29
> +++++++++++++++++++++++++
>  lib/librte_eal/linuxapp/eal/eal_pci.c           | 15 +++++++++++++
>  lib/librte_eal/linuxapp/eal/eal_pci_uio.c       | 10 +++++++++
>  lib/librte_eal/linuxapp/eal/rte_eal_version.map |  2 ++
>  4 files changed, 56 insertions(+)
>
> diff --git a/lib/librte_eal/common/include/rte_pci.h
> b/lib/librte_eal/common/include/rte_pci.h
> index 66ed793..a78081f 100644
> --- a/lib/librte_eal/common/include/rte_pci.h
> +++ b/lib/librte_eal/common/include/rte_pci.h
> @@ -152,6 +152,7 @@ struct rte_pci_device {
>         uint16_t max_vfs;                       /**< sriov enable if not
> zero */
>         int numa_node;                          /**< NUMA node connection
> */
>         struct rte_devargs *devargs;            /**< Device user arguments
> */
> +       int config_fd;                          /**< PCI config access */
>  };
>
>  /** Any PCI device identifier (vendor, device, ...) */
> @@ -298,6 +299,34 @@ void rte_eal_pci_register(struct rte_pci_driver
> *driver);
>   */
>  void rte_eal_pci_unregister(struct rte_pci_driver *driver);
>
> +/**
> + * Read PCI config space.
> + *
> + * @param device
> + *   A pointer to a rte_pci_device structure describing the device
> + *   to use
> + * @param buf
> + *   A data buffer where the bytes should be read into
> + * @param size
> + *   The length of the data buffer.
> + */
> +int rte_eal_pci_read_config(const struct rte_pci_device *device,
> +                           void *buf, size_t len, off_t offset);
> +
> +/**
> + * Write PCI config space.
> + *
> + * @param device
> + *   A pointer to a rte_pci_device structure describing the device
> + *   to use
> + * @param buf
> + *   A data buffer containing the bytes should be written
> + * @param size
> + *   The length of the data buffer.
> + */
> +int rte_eal_pci_write_config(const struct rte_pci_device *device,
> +                            const void *buf, size_t len, off_t offset);
> +
>  #ifdef __cplusplus
>  }
>  #endif
> diff --git a/lib/librte_eal/linuxapp/eal/eal_pci.c
> b/lib/librte_eal/linuxapp/eal/eal_pci.c
> index b5f5410..5bcfffa 100644
> --- a/lib/librte_eal/linuxapp/eal/eal_pci.c
> +++ b/lib/librte_eal/linuxapp/eal/eal_pci.c
> @@ -233,6 +233,7 @@ pci_scan_one(const char *dirname, uint16_t domain,
> uint8_t bus,
>         dev->addr.bus = bus;
>         dev->addr.devid = devid;
>         dev->addr.function = function;
> +       dev->config_fd = -1;
>
>         /* get vendor id */
>         snprintf(filename, sizeof(filename), "%s/vendor", dirname);
> @@ -592,6 +593,20 @@ rte_eal_pci_probe_one_driver(struct rte_pci_driver
> *dr, struct rte_pci_device *d
>         return 1;
>  }
>
> +/* Read PCI config space. */
> +int rte_eal_pci_read_config(const struct rte_pci_device *device,
> +                           void *buf, size_t len, off_t offset)
> +{
> +       return pread(device->config_fd, buf, len, offset);
> +}
> +
> +/* Write PCI config space. */
> +int rte_eal_pci_write_config(const struct rte_pci_device *device,
> +                            const void *buf, size_t len, off_t offset)
> +{
> +       return pwrite(device->config_fd, buf, len, offset);
> +}
> +
>  /* Init the PCI EAL subsystem */
>  int
>  rte_eal_pci_init(void)
> diff --git a/lib/librte_eal/linuxapp/eal/eal_pci_uio.c
> b/lib/librte_eal/linuxapp/eal/eal_pci_uio.c
> index e53f06b..0396eaa 100644
> --- a/lib/librte_eal/linuxapp/eal/eal_pci_uio.c
> +++ b/lib/librte_eal/linuxapp/eal/eal_pci_uio.c
> @@ -213,6 +213,7 @@ pci_get_uio_dev(struct rte_pci_device *dev, char
> *dstbuf,
>         struct dirent *e;
>         DIR *dir;
>         char dirname[PATH_MAX];
> +       char filename[PATH_MAX];
>
>         /* depending on kernel version, uio can be located in uio/uioX
>          * or uio:uioX */
> @@ -268,6 +269,15 @@ pci_get_uio_dev(struct rte_pci_device *dev, char
> *dstbuf,
>         if (e == NULL)
>                 return -1;
>
> +       /* Open fd for access to PCI config */
> +       snprintf(filename, sizeof(filename), "%s/device/config", dirname);
> +       dev->config_fd = open(filename, O_RDWR);
> +       if (dev->config_fd < 0) {
> +               RTE_LOG(ERR, EAL, "%s(): cannot open %s: %s\n",
> +                       __func__, filename, strerror(errno));
> +               return -1;
> +       }
> +
>         /* create uio device if we've been asked to */
>         if (internal_config.create_uio_dev &&
>                         pci_mknod_uio_dev(dstbuf, uio_num) < 0)
> diff --git a/lib/librte_eal/linuxapp/eal/rte_eal_version.map
> b/lib/librte_eal/linuxapp/eal/rte_eal_version.map
> index d36286e..626689c 100644
> --- a/lib/librte_eal/linuxapp/eal/rte_eal_version.map
> +++ b/lib/librte_eal/linuxapp/eal/rte_eal_version.map
> @@ -40,6 +40,8 @@ DPDK_2.0 {
>         rte_eal_pci_probe;
>         rte_eal_pci_register;
>         rte_eal_pci_unregister;
> +       rte_eal_pci_read_config;
> +       rte_eal_pci_write_config;
>         rte_eal_process_type;
>         rte_eal_remote_launch;
>         rte_eal_tailq_lookup;
> --
> 2.1.4
>
>


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