This is an example driver with little bit of kernel hack to test
ZONE_DEVICE based device memory management on POWER.
Signed-off-by: Anshuman Khandual <khand...@linux.vnet.ibm.com>
---
arch/powerpc/mm/init_64.c | 12 ++-
arch/powerpc/platforms/pseries/Makefile | 2 +-
arch/powerpc/platforms/pseries/rmem.c | 186 ++++++++++++++++++++++++++++++++
3 files changed, 198 insertions(+), 2 deletions(-)
create mode 100644 arch/powerpc/platforms/pseries/rmem.c
diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index db73708..5cc286d 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -351,6 +351,17 @@ int __meminit vmemmap_populate(unsigned long start,
unsigned long end, int node)
}
#ifdef CONFIG_MEMORY_HOTPLUG
+void dump_vmemmap(void)
+{
+ struct vmemmap_backing *vmem_back = vmemmap_list;
+
+ for (; vmem_back; vmem_back = vmem_back->list) {
+ printk("RMEM: vmemmap backing (%lx %lx)\n",
+ vmem_back->virt_addr, vmem_back->phys);
+ }
+}
+EXPORT_SYMBOL(dump_vmemmap);
+
static unsigned long vmemmap_list_free(unsigned long start)
{
struct vmemmap_backing *vmem_back, *vmem_back_prev;
@@ -482,5 +493,4 @@ struct page *realmode_pfn_to_page(unsigned long pfn)
return page;
}
EXPORT_SYMBOL_GPL(realmode_pfn_to_page);
-
#endif /* CONFIG_SPARSEMEM_VMEMMAP/CONFIG_FLATMEM */
diff --git a/arch/powerpc/platforms/pseries/Makefile
b/arch/powerpc/platforms/pseries/Makefile
index fedc2ccf0..20a5e23 100644
--- a/arch/powerpc/platforms/pseries/Makefile
+++ b/arch/powerpc/platforms/pseries/Makefile
@@ -5,7 +5,7 @@ obj-y := lpar.o hvCall.o nvram.o reconfig.o \
of_helpers.o \
setup.o iommu.o event_sources.o ras.o \
firmware.o power.o dlpar.o mobility.o rng.o \
- pci.o pci_dlpar.o eeh_pseries.o msi.o
+ pci.o pci_dlpar.o eeh_pseries.o msi.o rmem.o
obj-$(CONFIG_SMP) += smp.o
obj-$(CONFIG_SCANLOG) += scanlog.o
obj-$(CONFIG_KEXEC) += kexec.o
diff --git a/arch/powerpc/platforms/pseries/rmem.c
b/arch/powerpc/platforms/pseries/rmem.c
new file mode 100644
index 0000000..8c2287a
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/rmem.c
@@ -0,0 +1,186 @@
+/*
+ * Copyright (C) 2016 Anshuman Khandual (khand...@linux.vnet.ibm.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/gfp.h>
+#include <linux/kthread.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/memremap.h>
+
+#include <asm/firmware.h>
+#include <asm/hvcall.h>
+#include <asm/mmu.h>
+#include <asm/pgalloc.h>
+#include <asm/uaccess.h>
+#include <linux/memory.h>
+#include <asm/plpar_wrappers.h>
+#include <asm/prom.h>
+
+#define DEVM_MAP_SIZE (1UL << PA_SECTION_SHIFT) * 8
+
+extern void dump_vmemmap(void);
+extern struct resmem rmem;
+
+unsigned long devmem_start;
+unsigned long devmem_end;
+
+void driver_test_devmem(void)
+{
+ unsigned long i;
+ unsigned long start = devmem_start >> PAGE_SHIFT;
+ unsigned long end = devmem_end >> PAGE_SHIFT;
+
+ for(i = start; i < end; i++)
+ *(unsigned long *)i = (char)i;
+
+ for(i = start; i < end; i++) {
+ if (*(unsigned long *)i != (char)i)
+ printk("RMEM: Error data miscompare at %lx\n", i);
+ }
+ printk("RMEM: Data integrity test successful\n");
+}
+
+void driver_memory(unsigned long start_pfn, unsigned long end_pfn)
+{
+ printk("RMEM: Driver now owns PFN(%lx....%lx)\n", start_pfn, end_pfn);
+
+ devmem_start = start_pfn;
+ devmem_end = end_pfn;
+ driver_test_devmem();
+}
+
+static void dump_reserved(void)
+{
+ unsigned long i;
+
+ printk("RMEM: Reserved memory sections\n");
+ for (i = 0; i < rmem.nr; i++) {
+ printk("RMEM: Base %llx Size: %llx Node: %llu\n",
+ rmem.mem[i][MEM_BASE], rmem.mem[i][MEM_SIZE],
+ rmem.mem[i][MEM_NODE]);
+ }
+}
+
+static void dump_devmap(resource_size_t start)
+{
+ struct vmem_altmap *altmap;
+ struct dev_pagemap *pgmap;
+ struct page_map *pmap;
+ struct page *page;
+ unsigned long pfn;
+
+ altmap = to_vmem_altmap((unsigned long)pfn_to_page(start >>
PAGE_SHIFT));
+ if (altmap) {
+ printk("RMEM: altmap->base_pfn %lu\n", altmap->base_pfn);
+ printk("RMEM: altmap->reserve %lu\n", altmap->reserve);
+ printk("RMEM: altmap->free %lu\n", altmap->free);
+ printk("RMEM: altmap->align %lu\n", altmap->align);
+ printk("RMEM: altmap->alloc %lu\n", altmap->alloc);
+ }
+ pmap = find_pagemap(start);
+ rcu_read_lock();
+ pgmap = find_dev_pagemap(start);
+ rcu_read_unlock();
+ printk("RMEM: pagemap (%lx)\n", (unsigned long)pmap);
+ printk("RMEM: dev_pagemap (%lx)\n", (unsigned long)pgmap);
+ printk("RMEM: pfn range (%lx %lx)\n", pfn_first(pmap), pfn_end(pmap));
+
+ for (pfn = pfn_first(pmap); pfn < pfn_end(pmap); pfn++) {
+ page = pfn_to_page(pfn);
+ printk("DEVM: pfn(%lx) page(%lx) pagemap(%lx) flags(%lx)\n",
+ pfn, (unsigned long)page, (unsigned long)page->pgmap,
+ page->flags);
+ }
+ driver_memory(pfn_first(pmap), pfn_end(pmap));
+}
+
+static void simple_translation_test(void __pmem *vaddr)
+{
+ unsigned long i;
+
+ if (vaddr) {
+ unsigned long tmp;
+
+ for (i = 0; i < DEVM_MAP_SIZE; i++)
+ tmp = *((unsigned long *)vaddr + i);
+
+ printk("RMEM: Read access complete (%lx %lx)\n",
+ (unsigned long)vaddr, DEVM_MAP_SIZE);
+ }
+}
+
+static int rmem_init(void)
+{
+ struct class *class;
+ struct device *dev;
+ struct resource *res;
+ struct percpu_ref *ref;
+ void __pmem *vaddr;
+ struct vmem_altmap *altmap;
+ struct vmem_altmap __altmap = {
+ .base_pfn = rmem.mem[0][0] >> PAGE_SHIFT,
+ .reserve = 0,
+ .free = 0x100,
+ .alloc = 0,
+ .align = 0,
+ };
+
+ printk("RMEM: Driver loaded\n");
+ dump_reserved();
+
+ class = class_create(THIS_MODULE, "rmem");
+ if (!class) {
+ printk("RMEM: class_create() failed\n");
+ goto out;
+ }
+
+ dev = device_create(class, NULL, MKDEV(100, 100), NULL, "rmem");
+ if (!dev) {
+ printk("RMEM: device_create() failed\n");
+ goto out;
+ }
+
+ res = devm_kzalloc(dev, sizeof(*res), GFP_KERNEL);
+ if (!res) {
+ printk("RMEM: devm_kzalloc() failed\n");
+ goto out;
+ }
+
+ ref = devm_kzalloc(dev, sizeof(*ref), GFP_KERNEL);
+ if (!res) {
+ printk("RMEM: devm_kzalloc() failed\n");
+ goto out;
+ }
+
+ dump_vmemmap();
+ altmap = &__altmap;
+ res->start = rmem.mem[0][0];
+ res->end = rmem.mem[0][0] + DEVM_MAP_SIZE;
+ vaddr = devm_memremap_pages(dev, res, ref, altmap);
+ dump_vmemmap();
+
+ simple_translation_test(vaddr);
+ dump_devmap(res->start);
+ return 0;
+out:
+ return -1;
+}
+
+static void rmem_exit(void)
+{
+ printk("RMEM: rmem driver unloaded\n");
+}
+
+module_init(rmem_init);
+module_exit(rmem_exit);
+
+MODULE_AUTHOR("Anshuman Khandual <khand...@linux.vnet.ibm.com>");
+MODULE_DESCRIPTION("Test driver for device memory");
+MODULE_LICENSE("GPL");
--
1.8.3.1
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