Re: [PATCH 6/6] virtio: arm/arm64: memory mapped IO support in pmd driver

[Stephen Hemminger <stephen@networkplumber.org>]

On Fri,  4 Dec 2015 23:05:19 +0530
Santosh Shukla <sshukla@mvista.com> wrote:

>  
> +#ifdef RTE_EXEC_ENV_LINUXAPP
> +/* start address of first pci_iobar slot (user-space virtual-addres) */
> +void *ioport_map;
> +#if defined(RTE_ARCH_ARM) || defined(RTE_ARCH_ARM64)
> +
> +#include <sys/mman.h>
> +#define DEV_NAME		"/dev/igb_ioport"
> +
> +/* Keeping pci_ioport_size = 4k.
> + * So maximum mmaped pci_iobar supported =
> + * (ioport_size/pci_dev->mem_resource[0].len)
> + *
> + * note: kernel could allow maximum 32 virtio-net-pci interface, that mean
> + * maximum 32 PCI_IOBAR(s) where each PCI_IOBAR_LEN=0x20, so virtio_map_ioport()
> + * func by theory gonna support 4k/0x20 ==> 128 PCI_IOBAR(s), more than
> + * max-virtio-net-pci interface.
> + */
> +#define PAGE_SIZE		4096
> +#define PCI_IOPORT_SIZE		PAGE_SIZE
> +#define PCI_IOPORT_MAX		128 /* 4k / 0x20 */
> +
> +int ioport_map_cnt;
> +#endif /* ARM, ARM64 */
> +#endif /* RTE_EXEC_ENV_LINUXAPP */

These variables should be static.

Also, it is should be possible to extract the I/O bar stuff in a generic way through sysfs
and not depend on a character device. The long term goal for DPDK acceptance is to
eliminate (or at least reduce to a minumum) any requirement for special kernel drivers.