On Thu, Nov 16, 2017 at 04:51:30AM +1100, Oliver O'Halloran wrote:
> A fairly bare-bones set of device-tree bindings so libnvdimm can be used
> on powerpc and other device-tree based platforms.
>
> Cc: devicetree@xxxxxxxxxxxxxxx
> Signed-off-by: Oliver O'Halloran <oohall@xxxxxxxxx>
> ---
> .../devicetree/bindings/nvdimm/nvdimm-bus.txt | 69 +++++++
> MAINTAINERS | 8 +
> drivers/nvdimm/Kconfig | 10 +
> drivers/nvdimm/Makefile | 1 +
> drivers/nvdimm/of_nvdimm.c | 202 +++++++++++++++++++++
> 5 files changed, 290 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/nvdimm/nvdimm-bus.txt
> create mode 100644 drivers/nvdimm/of_nvdimm.c
>
> diff --git a/Documentation/devicetree/bindings/nvdimm/nvdimm-bus.txt b/Documentation/devicetree/bindings/nvdimm/nvdimm-bus.txt
> new file mode 100644
> index 000000000000..491e7c4900ed
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/nvdimm/nvdimm-bus.txt
> @@ -0,0 +1,69 @@
> +Device-tree bindings for nonvolatile-memory / NVDIMMs
> +-----------------------------------------------------
> +
> +Non-volatile DIMMs are memory modules used to provide (cacheable) main memory that
> +retains its contents across power cycles. In more practical terms, they are kind
> +of storage device where the contents can be accessed by the CPU directly,
> +rather than indirectly via a storage controller or similar. This can provide
> +substantial performance improvements for applications designed to take
> +advantage of in-memory storage.
> +
> +This binding provides a way to describe memory regions that should be managed
> +by an NVDIMM storage driver (libNVDIMM in Linux) and some of the associated
> +metadata. The binding itself is split into two main parts: A container bus and
> +its sub-nodes which describe which memory address ranges corresponding to
> +NVDIMM backed memory.
> +
> +Bindings for the container bus:
> +------------------------------
> +
> +Required properties:
> + - compatible = "nvdimm-bus";
> + - ranges;
> + A blank ranges property is required because the sub-nodes have
> + addresses in the system's physical address space.
> +
> +The use of a container bus is mainly to handle future expansion of the binding. For
> +comparison the ACPI equivalent of this binding (NFIT) describes: Memory regions, DIMM
> +control structures, Block mode DIMM control structures, interleave sets, and more. Some
> +of these structures cross reference each other so everyone should be happier if we keep
> +it relatively self contained.
Will adding any of these things need unit addresses and colide with the
existing nodes below? IOW, at one level there's only 1 number space.
> +
> +Bindings for the region nodes:
> +-----------------------------
> +
> +Required properties:
> + - compatible = "nvdimm-persistent" or "nvdimm-volatile"
> +
> + The "nvdimm-persistent" region type indicates that this memory region
> + is actually a persistent region. The volatile type is mainly useful
> + for testing and RAM disks that can persist across kexec.
> +
> + - reg = <base, size>;
> + The reg property should only contain one address range.
> +
> +Optional properties:
> + - Any relevant NUMA assocativity properties for the target platform.
> +
> +A complete example:
> +--------------------
> +
> +/ {
> + #size-cells = <1>;
> + #address-cells = <1>;
> +
> + nonvolatile-memory {
> + compatible = "nonvolatile-memory";
> + ranges;
> +
> + region@5000 {
> + compatible = "nvdimm-persistent";
> + reg = <0x5000 0x1000>;
> + };
> +
> + region@6000 {
> + compatible = "nvdimm-volatile";
> + reg = <0x6000 0x1000>;
> + };
> + };
> +};
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 65eff7857ec3..0350bf5a94d2 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -7875,6 +7875,14 @@ Q: https://patchwork.kernel.org/project/linux-nvdimm/list/
> S: Supported
> F: drivers/nvdimm/pmem*
>
> +LIBNVDIMM: DEVICETREE BINDINGS
> +M: Oliver O'Halloran <oohall@xxxxxxxxx>
> +L: linux-nvdimm@xxxxxxxxxxxx
> +Q: https://patchwork.kernel.org/project/linux-nvdimm/list/
> +S: Supported
> +F: drivers/nvdimm/of_nvdimm.c
> +F: Documentation/devicetree/bindings/nvdimm/nvdimm-bus.txt
> +
> LIBNVDIMM: NON-VOLATILE MEMORY DEVICE SUBSYSTEM
> M: Dan Williams <dan.j.williams@xxxxxxxxx>
> L: linux-nvdimm@xxxxxxxxxxxx
> diff --git a/drivers/nvdimm/Kconfig b/drivers/nvdimm/Kconfig
> index 5bdd499b5f4f..72d147b55596 100644
> --- a/drivers/nvdimm/Kconfig
> +++ b/drivers/nvdimm/Kconfig
> @@ -102,4 +102,14 @@ config NVDIMM_DAX
>
> Select Y if unsure
>
> +config OF_NVDIMM
> + tristate "Device-tree support for NVDIMMs"
> + depends on OF
> + default LIBNVDIMM
> + help
> + Allows byte addressable persistent memory regions to be described in the
> + device-tree.
> +
> + Select Y if unsure.
> +
> endif
> diff --git a/drivers/nvdimm/Makefile b/drivers/nvdimm/Makefile
> index ca6d325438a3..9029511a8486 100644
> --- a/drivers/nvdimm/Makefile
> +++ b/drivers/nvdimm/Makefile
> @@ -3,6 +3,7 @@ obj-$(CONFIG_BLK_DEV_PMEM) += nd_pmem.o
> obj-$(CONFIG_ND_BTT) += nd_btt.o
> obj-$(CONFIG_ND_BLK) += nd_blk.o
> obj-$(CONFIG_X86_PMEM_LEGACY) += nd_e820.o
> +obj-$(CONFIG_OF_NVDIMM) += of_nvdimm.o
>
> nd_pmem-y := pmem.o
>
> diff --git a/drivers/nvdimm/of_nvdimm.c b/drivers/nvdimm/of_nvdimm.c
> new file mode 100644
> index 000000000000..765cbbae8bcb
> --- /dev/null
> +++ b/drivers/nvdimm/of_nvdimm.c
> @@ -0,0 +1,202 @@
> +/*
> + * Copyright 2017, IBM Corporation
> + *
> + * 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.
> + *
> + * 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.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, you can access it online at
> + * http://www.gnu.org/licenses/gpl-2.0.html.
This can be SPDX tag.
> + */
> +
> +#define pr_fmt(fmt) "of_nvdimm: " fmt
> +
> +#include <linux/of_platform.h>
> +#include <linux/of_address.h>
> +#include <linux/libnvdimm.h>
> +#include <linux/module.h>
> +#include <linux/ioport.h>
> +#include <linux/slab.h>
> +
> +static const struct attribute_group *region_attr_groups[] = {
> + &nd_region_attribute_group,
> + &nd_device_attribute_group,
> + NULL,
> +};
> +
> +static int of_nvdimm_add_byte(struct nvdimm_bus *bus, struct device_node *np)
_add_byte_region() would be more clear.
> +{
> + struct nd_region_desc ndr_desc;
> + struct resource temp_res;
> + struct nd_region *region;
> +
> + /*
> + * byte regions should only have one address range
> + */
> + if (of_address_to_resource(np, 0, &temp_res)) {
> + pr_warn("Unable to parse reg[0] for %pOF\n", np);
> + return -ENXIO;
> + }
> +
> + pr_debug("Found %pR for %pOF\n", &temp_res, np);
> +
> + memset(&ndr_desc, 0, sizeof(ndr_desc));
> + ndr_desc.res = &temp_res;
> + ndr_desc.of_node = np;
> + ndr_desc.attr_groups = region_attr_groups;
> +#ifdef CONFIG_NUMA
I believe of_node_to_nid will do the right thing for !CONFIG_NUMA and
this can be dropped.
> + ndr_desc.numa_node = of_node_to_nid(np);
> +#endif
> + set_bit(ND_REGION_PAGEMAP, &ndr_desc.flags);
> +
> + if (of_device_is_compatible(np, "nvdimm-volatile"))
You've already matched the node once with of_match_node, don't do it
again.
> + region = nvdimm_volatile_region_create(bus, &ndr_desc);
> + else
> + region = nvdimm_pmem_region_create(bus, &ndr_desc);
> +
> + if (!region)
> + return -ENXIO;
> +
> + return 0;
> +}
> +
> +static const struct of_device_id of_nvdimm_dev_types[] = {
> + { .compatible = "nvdimm-persistent", .data = of_nvdimm_add_byte },
> + { .compatible = "nvdimm-volatile", .data = of_nvdimm_add_byte },
> + { },
> +};
> +
> +static void of_nvdimm_parse_one(struct nvdimm_bus *bus,
> + struct device_node *node)
> +{
> + int (*parse_node)(struct nvdimm_bus *, struct device_node *);
> + const struct of_device_id *match;
> + int rc;
> +
> + if (of_node_test_and_set_flag(node, OF_POPULATED)) {
Why not make the regions platform devices too? Then you don't need your
own populate code.
> + pr_debug("%pOF already parsed, skipping\n", node);
> + return;
> + }
> +
> + match = of_match_node(of_nvdimm_dev_types, node);
> + if (!match) {
> + pr_info("No compatible match for '%pOF'\n", node);
> + of_node_clear_flag(node, OF_POPULATED);
> + return;
> + }
> +
> + of_node_get(node);
> + parse_node = match->data;
This makes no sense. I assume you plan to add some other region type
later?
> + rc = parse_node(bus, node);
> +
> + if (rc) {
> + of_node_clear_flag(node, OF_POPULATED);
> + of_node_put(node);
> + }
> +
> + pr_debug("Parsed %pOF, rc = %d\n", node, rc);
> +
> + return;
> +}
> +
> +/*
> + * The nvdimm core refers to the bus descriptor structure at runtime
> + * so we need to keep it around. Note that that this is different to
> + * the other nd_*_desc types which are essentially containers for extra
> + * function parameters.
> + */
> +struct of_nd_private {
> + struct nvdimm_bus_descriptor desc;
> + struct nvdimm_bus *bus;
> +};
> +
> +static const struct attribute_group *bus_attr_groups[] = {
> + &nvdimm_bus_attribute_group,
> + NULL,
> +};
> +
> +static int of_nvdimm_probe(struct platform_device *pdev)
> +{
> + struct device_node *node, *child;
> + struct of_nd_private *priv;
> +
> + node = dev_of_node(&pdev->dev);
> + if (!node)
> + return -ENXIO;
> +
> + priv = kzalloc(sizeof(*priv), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
> +
> + priv->desc.attr_groups = bus_attr_groups;
> + priv->desc.provider_name = "of_nvdimm";
> + priv->desc.module = THIS_MODULE;
> + priv->desc.of_node = node;
> +
> + priv->bus = nvdimm_bus_register(&pdev->dev, &priv->desc);
> + if (!priv->bus)
> + goto err;
> +
> + platform_set_drvdata(pdev, priv);
> +
> + /* now walk the node bus and setup regions, etc */
> + for_each_available_child_of_node(node, child)
> + of_nvdimm_parse_one(priv->bus, child);
> +
> + return 0;
> +
> +err:
> + nvdimm_bus_unregister(priv->bus);
> + kfree(priv);
> + return -ENXIO;
> +}
> +
> +static int of_nvdimm_remove(struct platform_device *pdev)
> +{
> + struct of_nd_private *priv = platform_get_drvdata(pdev);
> + struct device_node *node;
> +
> + if (!priv)
> + return 0; /* possible? */
> +
> + for_each_available_child_of_node(pdev->dev.of_node, node) {
> + if (!of_node_check_flag(node, OF_POPULATED))
> + continue;
> +
> + of_node_clear_flag(node, OF_POPULATED);
> + of_node_put(node);
> + pr_debug("de-populating %s\n", node->full_name);
> + }
> +
> + nvdimm_bus_unregister(priv->bus);
> + kfree(priv);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id of_nvdimm_bus_match[] = {
> + { .compatible = "nvdimm-bus" },
> + { },
> +};
> +
> +static const struct platform_driver of_nvdimm_driver = {
> + .probe = of_nvdimm_probe,
> + .remove = of_nvdimm_remove,
> + .driver = {
> + .name = "of_nvdimm",
> + .owner = THIS_MODULE,
> + .of_match_table = of_nvdimm_bus_match,
> + },
> +};
> +
> +module_platform_driver(of_nvdimm_driver);
> +MODULE_DEVICE_TABLE(of, of_nvdimm_bus_match);
> +MODULE_LICENSE("GPL v2");
> +MODULE_AUTHOR("IBM Corporation");
> --
> 2.9.5
>
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