From mboxrd@z Thu Jan  1 00:00:00 1970
From: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Subject: Re: [PATCH 3/3] virtio: Add a new layer to abstract pci
	access method
Date: Mon, 18 Jan 2016 21:46:45 +0800
Message-ID: <20160118134645.GC19531@yliu-dev.sh.intel.com>
References: <1453108389-21006-1-git-send-email-mukawa@igel.co.jp>
 <1453108389-21006-4-git-send-email-mukawa@igel.co.jp>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Cc: dev@dpdk.org
To: Tetsuya Mukawa <mukawa@igel.co.jp>
Return-path: <dev-bounces@dpdk.org>
Received: from mga03.intel.com (mga03.intel.com [134.134.136.65])
 by dpdk.org (Postfix) with ESMTP id E115E5A32
 for <dev@dpdk.org>; Mon, 18 Jan 2016 14:45:02 +0100 (CET)
Content-Disposition: inline
In-Reply-To: <1453108389-21006-4-git-send-email-mukawa@igel.co.jp>
List-Id: patches and discussions about DPDK <dev.dpdk.org>
List-Unsubscribe: <http://dpdk.org/ml/options/dev>,
 <mailto:dev-request@dpdk.org?subject=unsubscribe>
List-Archive: <http://dpdk.org/ml/archives/dev/>
List-Post: <mailto:dev@dpdk.org>
List-Help: <mailto:dev-request@dpdk.org?subject=help>
List-Subscribe: <http://dpdk.org/ml/listinfo/dev>,
 <mailto:dev-request@dpdk.org?subject=subscribe>
Errors-To: dev-bounces@dpdk.org
Sender: "dev" <dev-bounces@dpdk.org>

On Mon, Jan 18, 2016 at 06:13:09PM +0900, Tetsuya Mukawa wrote:
> +struct virtio_pci_access_ops {
> +	uint8_t (*legacy_read8)(struct virtio_hw *hw, uint8_t *addr);
> +	uint16_t (*legacy_read16)(struct virtio_hw *hw, uint16_t *addr);
> +	uint32_t (*legacy_read32)(struct virtio_hw *hw, uint32_t *addr);
> +	void (*legacy_write8)(struct virtio_hw *hw,
> +				uint8_t *addr, uint8_t val);
> +	void (*legacy_write16)(struct virtio_hw *hw,
> +				uint16_t *addr, uint16_t val);
> +	void (*legacy_write32)(struct virtio_hw *hw,
> +				uint32_t *addr, uint32_t val);
> +
> +	uint8_t (*modern_read8)(struct virtio_hw *hw, uint8_t *addr);
> +	uint16_t (*modern_read16)(struct virtio_hw *hw, uint16_t *addr);
> +	uint32_t (*modern_read32)(struct virtio_hw *hw, uint32_t *addr);
> +	void (*modern_write8)(struct virtio_hw *hw,
> +				uint8_t *addr, uint8_t val);
> +	void (*modern_write16)(struct virtio_hw *hw,
> +				uint16_t *addr, uint16_t val);
> +	void (*modern_write32)(struct virtio_hw *hw,
> +				uint32_t *addr, uint32_t val);

One thing about abstraction is that you need define one set of operations,
instead of two similar sets. Thus, you need define following operations
only:

  - read8
  - read16
  - read32
  - write8
  - write16
  - write32

And make a proper assignment after the modern/legacy detection.

> +
> +	int (*map_pci_cfg)(struct virtio_hw *hw);
> +	void (*unmap_pci_cfg)(struct virtio_hw *hw);
> +	void *(*get_cfg_addr)(struct virtio_hw *hw,
> +				struct virtio_pci_cap *cap);
> +	int (*read_pci_cfg)(struct virtio_hw *hw,
> +				void *buf, size_t len, off_t offset);

It'd be good if you can post the patches that use above abstract
operations, so that people can tell if they are properly defined.

	--yliu