[RFC 1/4] libnvdimm: add to_{nvdimm,nd_region}_dev()

struct device contains the ->of_node pointer so that devices can be
assoicated with the device-tree node that created them on DT platforms.
libnvdimm hides the struct device for regions and nvdimm devices inside
of an opaque structure so this patch adds accessors for each to allow
the of_nvdimm driver to set the of_node pointer.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
---
 drivers/nvdimm/dimm_devs.c   | 6 ++++++
 drivers/nvdimm/region_devs.c | 6 ++++++
 include/linux/libnvdimm.h    | 2 ++
 3 files changed, 14 insertions(+)

diff --git a/drivers/nvdimm/dimm_devs.c b/drivers/nvdimm/dimm_devs.c
index f0d1b7e5de01..cbddac011181 100644
--- a/drivers/nvdimm/dimm_devs.c
+++ b/drivers/nvdimm/dimm_devs.c

@@ -227,6 +227,12 @@ struct nvdimm *to_nvdimm(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(to_nvdimm);
 
+struct device *to_nvdimm_dev(struct nvdimm *nvdimm)
+{
+	return &nvdimm->dev;
+}
+EXPORT_SYMBOL_GPL(to_nvdimm_dev);
+
 struct nvdimm *nd_blk_region_to_dimm(struct nd_blk_region *ndbr)
 {
 	struct nd_region *nd_region = &ndbr->nd_region;

diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index cbaab4210c39..6c3988135fd5 100644
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c

@@ -182,6 +182,12 @@ struct nd_region *to_nd_region(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(to_nd_region);
 
+struct device *to_nd_region_dev(struct nd_region *region)
+{
+	return &region->dev;
+}
+EXPORT_SYMBOL_GPL(to_nd_region_dev);
+
 struct nd_blk_region *to_nd_blk_region(struct device *dev)
 {
 	struct nd_region *nd_region = to_nd_region(dev);

diff --git a/include/linux/libnvdimm.h b/include/linux/libnvdimm.h
index 550761477005..10fbc523ff95 100644
--- a/include/linux/libnvdimm.h
+++ b/include/linux/libnvdimm.h

@@ -139,6 +139,8 @@ struct nd_region *to_nd_region(struct device *dev);
 struct nd_blk_region *to_nd_blk_region(struct device *dev);
 struct nvdimm_bus_descriptor *to_nd_desc(struct nvdimm_bus *nvdimm_bus);
 struct device *to_nvdimm_bus_dev(struct nvdimm_bus *nvdimm_bus);
+struct device *to_nvdimm_dev(struct nvdimm *nvdimm);
+struct device *to_nd_region_dev(struct nd_region *region);
 const char *nvdimm_name(struct nvdimm *nvdimm);
 struct kobject *nvdimm_kobj(struct nvdimm *nvdimm);
 unsigned long nvdimm_cmd_mask(struct nvdimm *nvdimm);

-- 
2.9.4

Adds powerpc64 implementations of:

	memcpy_flushcache()
	arch_wb_cache_pmem()
	arch_invalidate_pmem()

Which form the architecture-specific portition of the persistent memory
API. These functions provide cache-management primitives for the DAX
drivers and libNVDIMM.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
---
This should go on to of the ZONE_DEVICE patches. If you want a full tree
there's one here that's based on next-20170626 with Dan's libnvdimm-pending
branch merged in: https://github.com/oohal/linux/tree/ppc-nvdimm-4.13
---
 arch/powerpc/Kconfig            |  1 +
 arch/powerpc/include/asm/pmem.h | 42 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+)
 create mode 100644 arch/powerpc/include/asm/pmem.h

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 4526c9ba09b6..f551f3a26130 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig

@@ -127,6 +127,7 @@ config PPC
 	select ARCH_HAS_ELF_RANDOMIZE
 	select ARCH_HAS_FORTIFY_SOURCE
 	select ARCH_HAS_GCOV_PROFILE_ALL
+	select ARCH_HAS_PMEM_API                if PPC64
 	select ARCH_HAS_SCALED_CPUTIME		if VIRT_CPU_ACCOUNTING_NATIVE
 	select ARCH_HAS_SG_CHAIN
 	select ARCH_HAS_TICK_BROADCAST		if GENERIC_CLOCKEVENTS_BROADCAST

diff --git a/arch/powerpc/include/asm/pmem.h b/arch/powerpc/include/asm/pmem.h
new file mode 100644
index 000000000000..7b0282e420fc
--- /dev/null
+++ b/arch/powerpc/include/asm/pmem.h

@@ -0,0 +1,42 @@
+/*
+ * Copyright(c) 2017 IBM Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+#ifndef __ASM_PMEM_H__
+#define __ASM_PMEM_H__
+
+#include <linux/string.h>
+#include <asm/cacheflush.h>
+
+#ifdef CONFIG_ARCH_HAS_PMEM_API
+static inline void arch_wb_cache_pmem(void *addr, size_t size)
+{
+	unsigned long start = (unsigned long) addr;
+	flush_inval_dcache_range(start, start + size);
+}
+
+static inline void arch_invalidate_pmem(void *addr, size_t size)
+{
+	unsigned long start = (unsigned long) addr;
+	flush_inval_dcache_range(start, start + size);
+}
+
+static inline void *memcpy_flushcache(void *dest, const void *src, size_t size)
+{
+	unsigned long start = (unsigned long) dest;
+
+	memcpy(dest, src, size);
+	flush_inval_dcache_range(start, start + size);
+
+	return dest;
+}
+#endif /* CONFIG_ARCH_HAS_PMEM_API */
+#endif /* __ASM_PMEM_H__ */

-- 
2.9.4

Scan the devicetree for nonvolatile-memory buses and instantiate a
platform device for them.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
---
 arch/powerpc/platforms/powernv/opal.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index 59684b4af4d1..bd3ed78f6f04 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c

@@ -775,6 +775,9 @@ static int __init opal_init(void)
 	/* Create i2c platform devices */
 	opal_pdev_init("ibm,opal-i2c");
 
+	/* Handle non-volatile memory devices */
+	opal_pdev_init("nonvolatile-memory");
+
 	/* Setup a heatbeat thread if requested by OPAL */
 	opal_init_heartbeat();
 

-- 
2.9.4

On Tue, Jun 27, 2017 at 3:28 AM, Oliver O'Halloran [off-list ref] wrote:

struct device contains the ->of_node pointer so that devices can be
assoicated with the device-tree node that created them on DT platforms.
libnvdimm hides the struct device for regions and nvdimm devices inside
of an opaque structure so this patch adds accessors for each to allow
the of_nvdimm driver to set the of_node pointer.

I'd rather go the other way and pass in the of_node to the bus and
dimm registration routines. It's a generic property of the device so
we should handle it like other generic device properties that get set
at initialization time like 'attr_groups' in nvdimm_bus_descriptor, or
a new parameter to nvdimm_create().

On Tue, Jun 27, 2017 at 3:28 AM, Oliver O'Halloran [off-list ref] wrote:

Adds powerpc64 implementations of:

        memcpy_flushcache()
        arch_wb_cache_pmem()
        arch_invalidate_pmem()

Which form the architecture-specific portition of the persistent memory
API. These functions provide cache-management primitives for the DAX
drivers and libNVDIMM.

Ok, now that we have commit 0aed55af8834 "x86, uaccess: introduce
copy_from_iter_flushcache for pmem / cache-bypass operations" upstream
that changes the model for how an architecture advertises
pmem-specific cache management routines. CONFIG_ARCH_HAS_PMEM_API
causes the pmem driver to try to link to these helpers rather than
dummy fallbacks:

    arch_wb_cache_pmem
    arch_invalidate_pmem

....and CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE indicates that the arch has
all the needed "flushcache" apis:

    __copy_from_user_flushcache
    memcpy_page_flushcache
    memcpy_flushcache

On Tue, Jul 11, 2017 at 9:53 AM, Dan Williams [off-list ref] wrote:

On Tue, Jun 27, 2017 at 3:28 AM, Oliver O'Halloran [off-list ref] wrote:

quoted

struct device contains the ->of_node pointer so that devices can be
assoicated with the device-tree node that created them on DT platforms.
libnvdimm hides the struct device for regions and nvdimm devices inside
of an opaque structure so this patch adds accessors for each to allow
the of_nvdimm driver to set the of_node pointer.

I'd rather go the other way and pass in the of_node to the bus and
dimm registration routines. It's a generic property of the device so
we should handle it like other generic device properties that get set
at initialization time like 'attr_groups' in nvdimm_bus_descriptor, or
a new parameter to nvdimm_create().

Sure. I just figured it would be preferable to keep firmware specific
details inside the firmware driver rather than adding #ifdef CONFIG_OF
around the place. Do you have any objections to making nvdimm_create()
take a descriptor structure rather than adding a parameter?

On Mon, Jul 10, 2017 at 9:38 PM, Oliver [off-list ref] wrote:

On Tue, Jul 11, 2017 at 9:53 AM, Dan Williams [off-list ref] wrote:

quoted

On Tue, Jun 27, 2017 at 3:28 AM, Oliver O'Halloran [off-list ref] wrote:

quoted

struct device contains the ->of_node pointer so that devices can be
assoicated with the device-tree node that created them on DT platforms.
libnvdimm hides the struct device for regions and nvdimm devices inside
of an opaque structure so this patch adds accessors for each to allow
the of_nvdimm driver to set the of_node pointer.

I'd rather go the other way and pass in the of_node to the bus and
dimm registration routines. It's a generic property of the device so
we should handle it like other generic device properties that get set
at initialization time like 'attr_groups' in nvdimm_bus_descriptor, or
a new parameter to nvdimm_create().

Sure. I just figured it would be preferable to keep firmware specific
details inside the firmware driver rather than adding #ifdef CONFIG_OF
around the place. Do you have any objections to making nvdimm_create()
take a descriptor structure rather than adding a parameter?

I don't see why we need "#ifdef CONFIG_OF". It's just a "struct
of_node *" pointer that can be forward declared as "struct of_node;"
we don't need the full definition.

Yes, I'm fine with converting nvdimm_create() to a take a descriptor,