[v2,11/38] cxlflash: Adapter context support for OCXL

Add support to create and release the adapter contexts for OCXL and
provide means to specify certain contexts as a master.

The existing cxlflash core has a design requirement that each host will
have a single host context available by default. To satisfy this
requirement, one host adapter context is created when the hardware AFU is
initialized. This is returned by the get_context() fop.

Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Acked-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
---
 drivers/scsi/cxlflash/ocxl_hw.c | 90 +++++++++++++++++++++++++++++++++++++++++
 drivers/scsi/cxlflash/ocxl_hw.h |  6 +++
 2 files changed, 96 insertions(+)

Le 26/02/2018 à 23:21, Uma Krishnan a écrit :
> Add support to create and release the adapter contexts for OCXL and
> provide means to specify certain contexts as a master.
> 
> The existing cxlflash core has a design requirement that each host will
> have a single host context available by default. To satisfy this
> requirement, one host adapter context is created when the hardware AFU is
> initialized. This is returned by the get_context() fop.
> 
> Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
> Acked-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
> ---

Reviewed-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>

>   drivers/scsi/cxlflash/ocxl_hw.c | 90 +++++++++++++++++++++++++++++++++++++++++
>   drivers/scsi/cxlflash/ocxl_hw.h |  6 +++
>   2 files changed, 96 insertions(+)
> 
> diff --git a/drivers/scsi/cxlflash/ocxl_hw.c b/drivers/scsi/cxlflash/ocxl_hw.c
> index bd86eef..d75b873 100644
> --- a/drivers/scsi/cxlflash/ocxl_hw.c
> +++ b/drivers/scsi/cxlflash/ocxl_hw.c
> @@ -18,6 +18,80 @@
>   #include "ocxl_hw.h"
> 
>   /**
> + * ocxlflash_set_master() - sets the context as master
> + * @ctx_cookie:	Adapter context to set as master.
> + */
> +static void ocxlflash_set_master(void *ctx_cookie)
> +{
> +	struct ocxlflash_context *ctx = ctx_cookie;
> +
> +	ctx->master = true;
> +}
> +
> +/**
> + * ocxlflash_get_context() - obtains the context associated with the host
> + * @pdev:	PCI device associated with the host.
> + * @afu_cookie:	Hardware AFU associated with the host.
> + *
> + * Return: returns the pointer to host adapter context
> + */
> +static void *ocxlflash_get_context(struct pci_dev *pdev, void *afu_cookie)
> +{
> +	struct ocxl_hw_afu *afu = afu_cookie;
> +
> +	return afu->ocxl_ctx;
> +}
> +
> +/**
> + * ocxlflash_dev_context_init() - allocate and initialize an adapter context
> + * @pdev:	PCI device associated with the host.
> + * @afu_cookie:	Hardware AFU associated with the host.
> + *
> + * Return: returns the adapter context on success, ERR_PTR on failure
> + */
> +static void *ocxlflash_dev_context_init(struct pci_dev *pdev, void *afu_cookie)
> +{
> +	struct ocxl_hw_afu *afu = afu_cookie;
> +	struct device *dev = afu->dev;
> +	struct ocxlflash_context *ctx;
> +	int rc;
> +
> +	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
> +	if (unlikely(!ctx)) {
> +		dev_err(dev, "%s: Context allocation failed\n", __func__);
> +		rc = -ENOMEM;
> +		goto err;
> +	}
> +
> +	ctx->master = false;
> +	ctx->hw_afu = afu;
> +out:
> +	return ctx;
> +err:
> +	ctx = ERR_PTR(rc);
> +	goto out;
> +}
> +
> +/**
> + * ocxlflash_release_context() - releases an adapter context
> + * @ctx_cookie:	Adapter context to be released.
> + *
> + * Return: 0 on success, -errno on failure
> + */
> +static int ocxlflash_release_context(void *ctx_cookie)
> +{
> +	struct ocxlflash_context *ctx = ctx_cookie;
> +	int rc = 0;
> +
> +	if (!ctx)
> +		goto out;
> +
> +	kfree(ctx);
> +out:
> +	return rc;
> +}
> +
> +/**
>    * ocxlflash_destroy_afu() - destroy the AFU structure
>    * @afu_cookie:	AFU to be freed.
>    */
> @@ -28,6 +102,7 @@ static void ocxlflash_destroy_afu(void *afu_cookie)
>   	if (!afu)
>   		return;
> 
> +	ocxlflash_release_context(afu->ocxl_ctx);
>   	kfree(afu);
>   }
> 
> @@ -127,6 +202,7 @@ static int ocxlflash_config_afu(struct pci_dev *pdev, struct ocxl_hw_afu *afu)
>   static void *ocxlflash_create_afu(struct pci_dev *pdev)
>   {
>   	struct device *dev = &pdev->dev;
> +	struct ocxlflash_context *ctx;
>   	struct ocxl_hw_afu *afu;
>   	int rc;
> 
> @@ -152,6 +228,16 @@ static void *ocxlflash_create_afu(struct pci_dev *pdev)
>   			__func__, rc);
>   		goto err1;
>   	}
> +
> +	ctx = ocxlflash_dev_context_init(pdev, afu);
> +	if (IS_ERR(ctx)) {
> +		rc = PTR_ERR(ctx);
> +		dev_err(dev, "%s: ocxlflash_dev_context_init failed rc=%d\n",
> +			__func__, rc);
> +		goto err1;
> +	}
> +
> +	afu->ocxl_ctx = ctx;
>   out:
>   	return afu;
>   err1:
> @@ -163,6 +249,10 @@ static void *ocxlflash_create_afu(struct pci_dev *pdev)
>   /* Backend ops to ocxlflash services */
>   const struct cxlflash_backend_ops cxlflash_ocxl_ops = {
>   	.module			= THIS_MODULE,
> +	.set_master		= ocxlflash_set_master,
> +	.get_context		= ocxlflash_get_context,
> +	.dev_context_init	= ocxlflash_dev_context_init,
> +	.release_context	= ocxlflash_release_context,
>   	.create_afu		= ocxlflash_create_afu,
>   	.destroy_afu		= ocxlflash_destroy_afu,
>   };
> diff --git a/drivers/scsi/cxlflash/ocxl_hw.h b/drivers/scsi/cxlflash/ocxl_hw.h
> index a6f7796..de43c04 100644
> --- a/drivers/scsi/cxlflash/ocxl_hw.h
> +++ b/drivers/scsi/cxlflash/ocxl_hw.h
> @@ -14,6 +14,7 @@
> 
>   /* OCXL hardware AFU associated with the host */
>   struct ocxl_hw_afu {
> +	struct ocxlflash_context *ocxl_ctx; /* Host context */
>   	struct pci_dev *pdev;		/* PCI device */
>   	struct device *dev;		/* Generic device */
> 
> @@ -27,3 +28,8 @@ struct ocxl_hw_afu {
> 
>   	int max_pasid;			/* Maximum number of contexts */
>   };
> +
> +struct ocxlflash_context {
> +	struct ocxl_hw_afu *hw_afu;	/* HW AFU back pointer */
> +	bool master;			/* Whether this is a master context */
> +};
>