Le 03/12/2019 à 04:46, Alastair D'Silva a écrit :
From: Alastair D'Silva <alast...@d-silva.org>

Tally up the LPC memory on an OpenCAPI link & allow it to be mapped

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
  drivers/misc/ocxl/core.c          | 10 ++++++
  drivers/misc/ocxl/link.c          | 60 +++++++++++++++++++++++++++++++
  drivers/misc/ocxl/ocxl_internal.h | 33 +++++++++++++++++
  3 files changed, 103 insertions(+)

diff --git a/drivers/misc/ocxl/core.c b/drivers/misc/ocxl/core.c
index b7a09b21ab36..2531c6cf19a0 100644
--- a/drivers/misc/ocxl/core.c
+++ b/drivers/misc/ocxl/core.c
@@ -230,8 +230,18 @@ static int configure_afu(struct ocxl_afu *afu, u8 afu_idx, 
struct pci_dev *dev)
        if (rc)
                goto err_free_pasid;
+ if (afu->config.lpc_mem_size || afu->config.special_purpose_mem_size) {
+               rc = ocxl_link_add_lpc_mem(afu->fn->link, 
afu->config.lpc_mem_offset,
+                                          afu->config.lpc_mem_size +
+                                          
afu->config.special_purpose_mem_size);
+               if (rc)
+                       goto err_free_mmio;
+       }
+
        return 0;
+err_free_mmio:
+       unmap_mmio_areas(afu);
  err_free_pasid:
        reclaim_afu_pasid(afu);
  err_free_actag:
diff --git a/drivers/misc/ocxl/link.c b/drivers/misc/ocxl/link.c
index 58d111afd9f6..d8503f0dc6ec 100644
--- a/drivers/misc/ocxl/link.c
+++ b/drivers/misc/ocxl/link.c
@@ -84,6 +84,11 @@ struct ocxl_link {
        int dev;
        atomic_t irq_available;
        struct spa *spa;
+       struct mutex lpc_mem_lock;
+       u64 lpc_mem_sz; /* Total amount of LPC memory presented on the link */
+       u64 lpc_mem;
+       int lpc_consumers;
+
        void *platform_data;
  };
  static struct list_head links_list = LIST_HEAD_INIT(links_list);
@@ -396,6 +401,8 @@ static int alloc_link(struct pci_dev *dev, int PE_mask, 
struct ocxl_link **out_l
        if (rc)
                goto err_spa;
+ mutex_init(&link->lpc_mem_lock);
+
        /* platform specific hook */
        rc = pnv_ocxl_spa_setup(dev, link->spa->spa_mem, PE_mask,
                                &link->platform_data);
@@ -711,3 +718,56 @@ void ocxl_link_free_irq(void *link_handle, int hw_irq)
        atomic_inc(&link->irq_available);
  }
  EXPORT_SYMBOL_GPL(ocxl_link_free_irq);
+
+int ocxl_link_add_lpc_mem(void *link_handle, u64 offset, u64 size)
+{
+       struct ocxl_link *link = (struct ocxl_link *) link_handle;
+
+       // Check for overflow
+       if (offset > (offset + size))
+               return -EINVAL;
+
+       mutex_lock(&link->lpc_mem_lock);
+       link->lpc_mem_sz = max(link->lpc_mem_sz, offset + size);
+
+       mutex_unlock(&link->lpc_mem_lock);
+
+       return 0;
+}
+
+u64 ocxl_link_lpc_map(void *link_handle, struct pci_dev *pdev)
+{
+       struct ocxl_link *link = (struct ocxl_link *) link_handle;
+       u64 lpc_mem;
+
+       mutex_lock(&link->lpc_mem_lock);
+       if (link->lpc_mem) {
+               lpc_mem = link->lpc_mem;
+
+               link->lpc_consumers++;
+               mutex_unlock(&link->lpc_mem_lock);
+               return lpc_mem;
+       }
+
+       link->lpc_mem = pnv_ocxl_platform_lpc_setup(pdev, link->lpc_mem_sz);
+       if (link->lpc_mem)
+               link->lpc_consumers++;


So if we fail to setup the lpc access in opal, we don't increment link->lpc_consumers and we shouldn't call ocxl_link_lpc_release(). Is that always true? Risk is to trigger the warning in ocxl_link_lpc_release(). So maybe we should check link->lpc_mem first in ocxl_link_lpc_release() and exit early if no memory is mapped. It would probably avoid hitting the WARN on an error path for example.

   Fred


+       lpc_mem = link->lpc_mem;
+       mutex_unlock(&link->lpc_mem_lock);
+
+       return lpc_mem;
+}
+
+void ocxl_link_lpc_release(void *link_handle, struct pci_dev *pdev)
+{
+       struct ocxl_link *link = (struct ocxl_link *) link_handle;
+
+       mutex_lock(&link->lpc_mem_lock);
+       WARN_ON(--link->lpc_consumers < 0);
+       if (link->lpc_consumers == 0) {
+               pnv_ocxl_platform_lpc_release(pdev);
+               link->lpc_mem = 0;
+       }
+
+       mutex_unlock(&link->lpc_mem_lock);
+}
diff --git a/drivers/misc/ocxl/ocxl_internal.h 
b/drivers/misc/ocxl/ocxl_internal.h
index 97415afd79f3..20b417e00949 100644
--- a/drivers/misc/ocxl/ocxl_internal.h
+++ b/drivers/misc/ocxl/ocxl_internal.h
@@ -141,4 +141,37 @@ int ocxl_irq_offset_to_id(struct ocxl_context *ctx, u64 
offset);
  u64 ocxl_irq_id_to_offset(struct ocxl_context *ctx, int irq_id);
  void ocxl_afu_irq_free_all(struct ocxl_context *ctx);
+/**
+ * ocxl_link_add_lpc_mem() - Increment the amount of memory required by an 
OpenCAPI link
+ *
+ * @link_handle: The OpenCAPI link handle
+ * @offset: The offset of the memory to add
+ * @size: The amount of memory to increment by
+ *
+ * Return 0 on success, negative on overflow
+ */
+int ocxl_link_add_lpc_mem(void *link_handle, u64 offset, u64 size);
+
+/**
+ * ocxl_link_lpc_map() - Map the LPC memory for an OpenCAPI device
+ *
+ * Since LPC memory belongs to a link, the whole LPC memory available
+ * on the link bust be mapped in order to make it accessible to a device.
+ *
+ * @link_handle: The OpenCAPI link handle
+ * @pdev: A device that is on the link
+ */
+u64 ocxl_link_lpc_map(void *link_handle, struct pci_dev *pdev);
+
+/**
+ * ocxl_link_lpc_release() - Release the LPC memory device for an OpenCAPI 
device
+ *
+ * Offlines LPC memory on an OpenCAPI link for a device. If this is the
+ * last device on the link to release the memory, unmap it from the link.
+ *
+ * @link_handle: The OpenCAPI link handle
+ * @pdev: A device that is on the link
+ */
+void ocxl_link_lpc_release(void *link_handle, struct pci_dev *pdev);
+
  #endif /* _OCXL_INTERNAL_H_ */

_______________________________________________
Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org
To unsubscribe send an email to linux-nvdimm-le...@lists.01.org

Reply via email to