Re: [PATCH 04/10] powerpc: Map & release OpenCAPI LPC memory

From: Alastair D'Silva <redacted>

This patch adds platform support to map & release LPC memory.

Signed-off-by: Alastair D'Silva <redacted>
---
  arch/powerpc/include/asm/pnv-ocxl.h   |  2 ++
  arch/powerpc/platforms/powernv/ocxl.c | 41 +++++++++++++++++++++++++++
  include/linux/memory_hotplug.h        |  5 ++++
  mm/memory_hotplug.c                   |  3 +-
  4 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/include/asm/pnv-ocxl.h b/arch/powerpc/include/asm/pnv-ocxl.h
index 7de82647e761..f8f8ffb48aa8 100644
--- a/arch/powerpc/include/asm/pnv-ocxl.h
+++ b/arch/powerpc/include/asm/pnv-ocxl.h

@@ -32,5 +32,7 @@ extern int pnv_ocxl_spa_remove_pe_from_cache(void *platform_data, int pe_handle)
  
  extern int pnv_ocxl_alloc_xive_irq(u32 *irq, u64 *trigger_addr);
  extern void pnv_ocxl_free_xive_irq(u32 irq);
+extern u64 pnv_ocxl_platform_lpc_setup(struct pci_dev *pdev, u64 size);
+extern void pnv_ocxl_platform_lpc_release(struct pci_dev *pdev);
  
  #endif /* _ASM_PNV_OCXL_H */

diff --git a/arch/powerpc/platforms/powernv/ocxl.c b/arch/powerpc/platforms/powernv/ocxl.c
index 8c65aacda9c8..c6d4234e0aba 100644
--- a/arch/powerpc/platforms/powernv/ocxl.c
+++ b/arch/powerpc/platforms/powernv/ocxl.c

@@ -475,6 +475,47 @@ void pnv_ocxl_spa_release(void *platform_data)
  }
  EXPORT_SYMBOL_GPL(pnv_ocxl_spa_release);
  
+u64 pnv_ocxl_platform_lpc_setup(struct pci_dev *pdev, u64 size)
+{
+	struct pci_controller *hose = pci_bus_to_host(pdev->bus);
+	struct pnv_phb *phb = hose->private_data;
+	u32 bdfn = (pdev->bus->number << 8) | pdev->devfn;
+	u64 base_addr = 0;
+	int rc;
+
+	rc = opal_npu_mem_alloc(phb->opal_id, bdfn, size, &base_addr);
+	if (rc) {
+		dev_warn(&pdev->dev,
+			 "OPAL could not allocate LPC memory, rc=%d\n", rc);
+		return 0;
+	}
+
+	base_addr = be64_to_cpu(base_addr);
+
+	rc = check_hotplug_memory_addressable(base_addr >> PAGE_SHIFT,
+					      size >> PAGE_SHIFT);
+	if (rc)
+		return 0;
+
+	return base_addr;
+}
+EXPORT_SYMBOL_GPL(pnv_ocxl_platform_lpc_setup);
+
+void pnv_ocxl_platform_lpc_release(struct pci_dev *pdev)
+{
+	struct pci_controller *hose = pci_bus_to_host(pdev->bus);
+	struct pnv_phb *phb = hose->private_data;
+	u32 bdfn = (pdev->bus->number << 8) | pdev->devfn;
+	int rc;
+
+	rc = opal_npu_mem_release(phb->opal_id, bdfn);
+	if (rc)
+		dev_warn(&pdev->dev,
+			 "OPAL reported rc=%d when releasing LPC memory\n", rc);
+}
+EXPORT_SYMBOL_GPL(pnv_ocxl_platform_lpc_release);
+
+
  int pnv_ocxl_spa_remove_pe_from_cache(void *platform_data, int pe_handle)
  {
  	struct spa_data *data = (struct spa_data *) platform_data;

diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index f46ea71b4ffd..3f5f1a642abe 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h

@@ -339,6 +339,11 @@ static inline int remove_memory(int nid, u64 start, u64 size)
  static inline void __remove_memory(int nid, u64 start, u64 size) {}
  #endif /* CONFIG_MEMORY_HOTREMOVE */
  
+#if CONFIG_MEMORY_HOTPLUG_SPARSE
+int check_hotplug_memory_addressable(unsigned long pfn,
+		unsigned long nr_pages);
+#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
+
  extern void __ref free_area_init_core_hotplug(int nid);
  extern int __add_memory(int nid, u64 start, u64 size);
  extern int add_memory(int nid, u64 start, u64 size);

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 2cecf07b396f..b39827dbd071 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c

@@ -278,7 +278,7 @@ static int check_pfn_span(unsigned long pfn, unsigned long nr_pages,
  	return 0;
  }
  
-static int check_hotplug_memory_addressable(unsigned long pfn,
+int check_hotplug_memory_addressable(unsigned long pfn,
  					    unsigned long nr_pages)
  {
  	const u64 max_addr = PFN_PHYS(pfn + nr_pages) - 1;

@@ -294,6 +294,7 @@ static int check_hotplug_memory_addressable(unsigned long pfn,
  
  	return 0;
  }
+EXPORT_SYMBOL_GPL(check_hotplug_memory_addressable);