[PATCH 15/18] nvme: add a common helper to read Identify Controller data

[james_p_freyensee@linux.intel.com (J Freyensee)]

On Fri, 2015-10-16@07:58 +0200, Christoph Hellwig wrote:
> And add the 64-bit register read operation for it.

I apologize, but I am getting tripped up by the subject line of this
patch and then the following description.

To me, this patch sounds and looks like it is doing two distinct,
separate things, thereby two separate patches:

1. Add a helper function to read and cache Identify Controller data
2. Add a 64-bit read register function pointer to nvme_ctrl_ops

I think it was PATCH 6 of this series that introduced "int
(*reg_read32)()".  If it is easier, it would also make sense to also
add "int (*reg_read64)()" there, instead of its own separate patch.
 > 
> Signed-off-by: Christoph Hellwig <hch at lst.de>
> ---
>  drivers/nvme/host/core.c | 50 
> +++++++++++++++++++++++++++++++++++++++++++++
>  drivers/nvme/host/nvme.h |  4 ++++
>  drivers/nvme/host/pci.c  | 53 +++++++++++++++-----------------------
> ----------
>  3 files changed, 70 insertions(+), 37 deletions(-)
> 
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index 1b27fd9..3e88901 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -574,6 +574,56 @@ const struct block_device_operations nvme_fops = 
> {
>  	.revalidate_disk= nvme_revalidate_disk,
>  };
>  
> +/*
> + * Initialize the cached copies of the Identify data and various 
> controller
> + * register in our nvme_ctrl structure.  This should be called as 
> soon as
> + * the admin queue is fully up and running.
> + */
> +int nvme_init_identify(struct nvme_ctrl *ctrl)
> +{
> +	struct nvme_id_ctrl *id;
> +	u64 cap;
> +	int ret, page_shift;
> +
> +	ret = ctrl->ops->reg_read64(ctrl, NVME_REG_CAP, &cap);
> +	if (ret) {
> +		dev_err(ctrl->dev, "Reading CAP failed (%d)\n", 
> ret);
> +		return ret;
> +	}
> +	page_shift = NVME_CAP_MPSMIN(cap) + 12;
> +
> +	ret = nvme_identify_ctrl(ctrl, &id);
> +	if (ret) {
> +		dev_err(ctrl->dev, "Identify Controller failed 
> (%d)\n", ret);
> +		return -EIO;
> +	}
> +
> +	ctrl->oncs = le16_to_cpup(&id->oncs);
> +	ctrl->abort_limit = id->acl + 1;
> +	ctrl->vwc = id->vwc;
> +	memcpy(ctrl->serial, id->sn, sizeof(id->sn));
> +	memcpy(ctrl->model, id->mn, sizeof(id->mn));
> +	memcpy(ctrl->firmware_rev, id->fr, sizeof(id->fr));
> +	if (id->mdts)
> +		ctrl->max_hw_sectors = 1 << (id->mdts + page_shift - 
> 9);
> +
> +	if ((ctrl->quirks & NVME_QUIRK_STRIPE_SIZE) && id->vs[3]) {
> +		unsigned int max_hw_sectors;
> +
> +		ctrl->stripe_size = 1 << (id->vs[3] + page_shift);
> +		max_hw_sectors = ctrl->stripe_size >> (page_shift - 
> 9);
> +		if (ctrl->max_hw_sectors) {
> +			ctrl->max_hw_sectors = min(max_hw_sectors,
> +							ctrl
> ->max_hw_sectors);
> +		} else {
> +			ctrl->max_hw_sectors = max_hw_sectors;
> +		}
> +	}
> +
> +	kfree(id);
> +	return 0;
> +}
> +
>  static void nvme_free_ctrl(struct kref *kref)
>  {
>  	struct nvme_ctrl *ctrl = container_of(kref, struct 
> nvme_ctrl, kref);
> diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
> index 1ebd0da..48b221a 100644
> --- a/drivers/nvme/host/nvme.h
> +++ b/drivers/nvme/host/nvme.h
> @@ -50,6 +50,8 @@ struct nvme_ctrl {
>  	char serial[20];
>  	char model[40];
>  	char firmware_rev[8];
> +	u32 max_hw_sectors;
> +	u32 stripe_size;
>  	u16 oncs;
>  	u16 abort_limit;
>  	u8 event_limit;
> @@ -80,6 +82,7 @@ struct nvme_ns {
>  
>  struct nvme_ctrl_ops {
>  	int (*reg_read32)(struct nvme_ctrl *ctrl, u32 off, u32 
> *val);
> +	int (*reg_read64)(struct nvme_ctrl *ctrl, u32 off, u64 
> *val);
>  	void (*free_ctrl)(struct nvme_ctrl *ctrl);
>  };
>  
> @@ -161,6 +164,7 @@ static inline int nvme_error_status(u16 status)
>  }
>  
>  void nvme_put_ctrl(struct nvme_ctrl *ctrl);
> +int nvme_init_identify(struct nvme_ctrl *ctrl);
>  void nvme_put_ns(struct nvme_ns *ns);
>  
>  int nvme_submit_sync_cmd(struct request_queue *q, struct 
> nvme_command *cmd,
> diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
> index 2c13d7a..7a25d6f 100644
> --- a/drivers/nvme/host/pci.c
> +++ b/drivers/nvme/host/pci.c
> @@ -127,8 +127,6 @@ struct nvme_dev {
>  	struct work_struct probe_work;
>  	struct work_struct scan_work;
>  	bool subsystem;
> -	u32 max_hw_sectors;
> -	u32 stripe_size;
>  	u32 page_size;
>  	void __iomem *cmb;
>  	dma_addr_t cmb_dma_addr;
> @@ -1650,13 +1648,13 @@ static void nvme_alloc_ns(struct nvme_dev 
> *dev, unsigned nsid)
>  	list_add_tail(&ns->list, &dev->namespaces);
>  
>  	blk_queue_logical_block_size(ns->queue, 1 << ns->lba_shift);
> -	if (dev->max_hw_sectors) {
> -		blk_queue_max_hw_sectors(ns->queue, dev
> ->max_hw_sectors);
> +	if (dev->ctrl.max_hw_sectors) {
> +		blk_queue_max_hw_sectors(ns->queue, dev
> ->ctrl.max_hw_sectors);
>  		blk_queue_max_segments(ns->queue,
> -			((dev->max_hw_sectors << 9) / dev
> ->page_size) + 1);
> +			((dev->ctrl.max_hw_sectors << 9) / dev
> ->page_size) + 1);
>  	}
> -	if (dev->stripe_size)
> -		blk_queue_chunk_sectors(ns->queue, dev->stripe_size 
> >> 9);
> +	if (dev->ctrl.stripe_size)
> +		blk_queue_chunk_sectors(ns->queue, dev
> ->ctrl.stripe_size >> 9);
>  	if (dev->ctrl.vwc & NVME_CTRL_VWC_PRESENT)
>  		blk_queue_flush(ns->queue, REQ_FLUSH | REQ_FUA);
>  	blk_queue_virt_boundary(ns->queue, dev->page_size - 1);
> @@ -1992,36 +1990,10 @@ static void nvme_dev_scan(struct work_struct 
> *work)
>  static int nvme_dev_add(struct nvme_dev *dev)
>  {
>  	int res;
> -	struct nvme_id_ctrl *ctrl;
> -	int shift = NVME_CAP_MPSMIN(readq(dev->bar + NVME_REG_CAP)) 
> + 12;
> -
> -	res = nvme_identify_ctrl(&dev->ctrl, &ctrl);
> -	if (res) {
> -		dev_err(dev->dev, "Identify Controller failed 
> (%d)\n", res);
> -		return -EIO;
> -	}
> -
> -	dev->ctrl.oncs = le16_to_cpup(&ctrl->oncs);
> -	dev->ctrl.abort_limit = ctrl->acl + 1;
> -	dev->ctrl.vwc = ctrl->vwc;
> -	memcpy(dev->ctrl.serial, ctrl->sn, sizeof(ctrl->sn));
> -	memcpy(dev->ctrl.model, ctrl->mn, sizeof(ctrl->mn));
> -	memcpy(dev->ctrl.firmware_rev, ctrl->fr, sizeof(ctrl->fr));
> -	if (ctrl->mdts)
> -		dev->max_hw_sectors = 1 << (ctrl->mdts + shift - 9);
> -
> -	if ((dev->ctrl.quirks & NVME_QUIRK_STRIPE_SIZE) && ctrl
> ->vs[3]) {
> -		unsigned int max_hw_sectors;
> -
> -		dev->stripe_size = 1 << (ctrl->vs[3] + shift);
> -		max_hw_sectors = dev->stripe_size >> (shift - 9);
> -		if (dev->max_hw_sectors) {
> -			dev->max_hw_sectors = min(max_hw_sectors,
> -							dev
> ->max_hw_sectors);
> -		} else
> -			dev->max_hw_sectors = max_hw_sectors;
> -	}
> -	kfree(ctrl);
> +
> +	res = nvme_init_identify(&dev->ctrl);
> +	if (res)
> +		return res;
>  
>  	if (!dev->tagset.tags) {
>  		dev->tagset.ops = &nvme_mq_ops;
> @@ -2642,8 +2614,15 @@ static int nvme_pci_reg_read32(struct 
> nvme_ctrl *ctrl, u32 off, u32 *val)
>  	return 0;
>  }
>  
> +static int nvme_pci_reg_read64(struct nvme_ctrl *ctrl, u32 off, u64 
> *val)
> +{
> +	*val = readq(to_nvme_dev(ctrl)->bar + off);
> +	return 0;
> +}
> +
>  static const struct nvme_ctrl_ops nvme_pci_ctrl_ops = {
>  	.reg_read32		= nvme_pci_reg_read32,
> +	.reg_read64		= nvme_pci_reg_read64,
>  	.free_ctrl		= nvme_pci_free_ctrl,
>  };
>