[PATCH v4 07/25] ocxl: Add functions to map/unmap LPC memory

["Alastair D'Silva" <alastair@d-silva.org>]

Add functions to map/unmap LPC memory

Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
Acked-by: Frederic Barrat <fbarrat@linux.ibm.com>
---
 drivers/misc/ocxl/core.c          | 51 +++++++++++++++++++++++++++++++
 drivers/misc/ocxl/ocxl_internal.h |  3 ++
 include/misc/ocxl.h               | 21 +++++++++++++
 3 files changed, 75 insertions(+)

diff --git a/drivers/misc/ocxl/core.c b/drivers/misc/ocxl/core.c
index 2531c6cf19a0..75ff14e3882a 100644
--- a/drivers/misc/ocxl/core.c
+++ b/drivers/misc/ocxl/core.c
@@ -210,6 +210,56 @@ static void unmap_mmio_areas(struct ocxl_afu *afu)
 	release_fn_bar(afu->fn, afu->config.global_mmio_bar);
 }
 
+int ocxl_afu_map_lpc_mem(struct ocxl_afu *afu)
+{
+	struct pci_dev *dev = to_pci_dev(afu->fn->dev.parent);
+
+	if ((afu->config.lpc_mem_size + afu->config.special_purpose_mem_size) == 0)
+		return 0;
+
+	afu->lpc_base_addr = ocxl_link_lpc_map(afu->fn->link, dev);
+	if (afu->lpc_base_addr == 0)
+		return -EINVAL;
+
+	if (afu->config.lpc_mem_size > 0) {
+		afu->lpc_res.start = afu->lpc_base_addr + afu->config.lpc_mem_offset;
+		afu->lpc_res.end = afu->lpc_res.start + afu->config.lpc_mem_size - 1;
+	}
+
+	if (afu->config.special_purpose_mem_size > 0) {
+		afu->special_purpose_res.start = afu->lpc_base_addr +
+						 afu->config.special_purpose_mem_offset;
+		afu->special_purpose_res.end = afu->special_purpose_res.start +
+					       afu->config.special_purpose_mem_size - 1;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(ocxl_afu_map_lpc_mem);
+
+struct resource *ocxl_afu_lpc_mem(struct ocxl_afu *afu)
+{
+	return &afu->lpc_res;
+}
+EXPORT_SYMBOL_GPL(ocxl_afu_lpc_mem);
+
+static void unmap_lpc_mem(struct ocxl_afu *afu)
+{
+	struct pci_dev *dev = to_pci_dev(afu->fn->dev.parent);
+
+	if (afu->lpc_res.start || afu->special_purpose_res.start) {
+		void *link = afu->fn->link;
+
+		// only release the link when the the last consumer calls release
+		ocxl_link_lpc_release(link, dev);
+
+		afu->lpc_res.start = 0;
+		afu->lpc_res.end = 0;
+		afu->special_purpose_res.start = 0;
+		afu->special_purpose_res.end = 0;
+	}
+}
+
 static int configure_afu(struct ocxl_afu *afu, u8 afu_idx, struct pci_dev *dev)
 {
 	int rc;
@@ -251,6 +301,7 @@ static int configure_afu(struct ocxl_afu *afu, u8 afu_idx, struct pci_dev *dev)
 
 static void deconfigure_afu(struct ocxl_afu *afu)
 {
+	unmap_lpc_mem(afu);
 	unmap_mmio_areas(afu);
 	reclaim_afu_pasid(afu);
 	reclaim_afu_actag(afu);
diff --git a/drivers/misc/ocxl/ocxl_internal.h b/drivers/misc/ocxl/ocxl_internal.h
index 2d7575225bd7..7b975a89db7b 100644
--- a/drivers/misc/ocxl/ocxl_internal.h
+++ b/drivers/misc/ocxl/ocxl_internal.h
@@ -52,6 +52,9 @@ struct ocxl_afu {
 	void __iomem *global_mmio_ptr;
 	u64 pp_mmio_start;
 	void *private;
+	u64 lpc_base_addr; /* Covers both LPC & special purpose memory */
+	struct resource lpc_res;
+	struct resource special_purpose_res;
 };
 
 enum ocxl_context_status {
diff --git a/include/misc/ocxl.h b/include/misc/ocxl.h
index 357ef1aadbc0..d8b0b4d46bfb 100644
--- a/include/misc/ocxl.h
+++ b/include/misc/ocxl.h
@@ -203,6 +203,27 @@ int ocxl_irq_set_handler(struct ocxl_context *ctx, int irq_id,
 
 // AFU Metadata
 
+/**
+ * ocxl_afu_map_lpc_mem() - Map the LPC system & special purpose memory for an AFU
+ * Do not call this during device discovery, as there may me multiple
+ * devices on a link, and the memory is mapped for the whole link, not
+ * just one device. It should only be called after all devices have
+ * registered their memory on the link.
+ *
+ * @afu: The AFU that has the LPC memory to map
+ *
+ * Returns 0 on success, negative on failure
+ */
+int ocxl_afu_map_lpc_mem(struct ocxl_afu *afu);
+
+/**
+ * ocxl_afu_lpc_mem() - Get the physical address range of LPC memory for an AFU
+ * @afu: The AFU associated with the LPC memory
+ *
+ * Returns a pointer to the resource struct for the physical address range
+ */
+struct resource *ocxl_afu_lpc_mem(struct ocxl_afu *afu);
+
 /**
  * ocxl_afu_config() - Get a pointer to the config for an AFU
  * @afu: a pointer to the AFU to get the config for
-- 
2.24.1
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