Add support to create and release the adapter contexts for OpenCXL 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 <ukri...@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 677bc34..c5f5c81 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 a807656..f78e5c9 100644
--- a/drivers/scsi/cxlflash/ocxl_hw.h
+++ b/drivers/scsi/cxlflash/ocxl_hw.h
@@ -14,6 +14,7 @@
 
 /* OpenCXL 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 */
+};
-- 
2.1.0

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