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Commit b5beae5e authored by Oliver O'Halloran's avatar Oliver O'Halloran Committed by Michael Ellerman
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powerpc/pseries: Add driver for PAPR SCM regions 



Adds a driver that implements support for enabling and accessing PAPR
SCM regions. Unfortunately due to how the PAPR interface works we can't
use the existing of_pmem driver (yet) because:

 a) The guest is required to use the H_SCM_BIND_MEM h-call to add
    add the SCM region to it's physical address space, and
 b) There is currently no mechanism for relating a bare of_pmem region
    to the backing DIMM (or not-a-DIMM for our case).

Both of these are easily handled by rolling the functionality into a
seperate driver so here we are...

Acked-by: default avatarDan Williams <dan.j.williams@intel.com>
Signed-off-by: default avatarOliver O'Halloran <oohall@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 4c5d87db

arch/powerpc/platforms/pseries/Kconfig

+7 −0
Original line number Diff line number Diff line
@@ -138,3 +138,10 @@ config IBMEBUS 
	bool "Support for GX bus based adapters"

	help

	  Bus device driver for GX bus based adapters.



config PAPR_SCM

	depends on PPC_PSERIES && MEMORY_HOTPLUG

	select LIBNVDIMM

	tristate "Support for the PAPR Storage Class Memory interface"

	help

	  Enable access to hypervisor provided storage class memory.

arch/powerpc/platforms/pseries/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ obj-$(CONFIG_IO_EVENT_IRQ) += io_event_irq.o 
obj-$(CONFIG_LPARCFG)		+= lparcfg.o

obj-$(CONFIG_IBMVIO)		+= vio.o

obj-$(CONFIG_IBMEBUS)		+= ibmebus.o

obj-$(CONFIG_PAPR_SCM)		+= papr_scm.o



ifdef CONFIG_PPC_PSERIES

obj-$(CONFIG_SUSPEND)		+= suspend.o

arch/powerpc/platforms/pseries/papr_scm.c

0 → 100644
+345 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0



#define pr_fmt(fmt)	"papr-scm: " fmt



#include <linux/of.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/ioport.h>

#include <linux/slab.h>

#include <linux/ndctl.h>

#include <linux/sched.h>

#include <linux/libnvdimm.h>

#include <linux/platform_device.h>



#include <asm/plpar_wrappers.h>



#define BIND_ANY_ADDR (~0ul)



#define PAPR_SCM_DIMM_CMD_MASK \

	((1ul << ND_CMD_GET_CONFIG_SIZE) | \

	 (1ul << ND_CMD_GET_CONFIG_DATA) | \

	 (1ul << ND_CMD_SET_CONFIG_DATA))



struct papr_scm_priv {

	struct platform_device *pdev;

	struct device_node *dn;

	uint32_t drc_index;

	uint64_t blocks;

	uint64_t block_size;

	int metadata_size;



	uint64_t bound_addr;



	struct nvdimm_bus_descriptor bus_desc;

	struct nvdimm_bus *bus;

	struct nvdimm *nvdimm;

	struct resource res;

	struct nd_region *region;

	struct nd_interleave_set nd_set;

};



static int drc_pmem_bind(struct papr_scm_priv *p)

{

	unsigned long ret[PLPAR_HCALL_BUFSIZE];

	uint64_t rc, token;



	/*

	 * When the hypervisor cannot map all the requested memory in a single

	 * hcall it returns H_BUSY and we call again with the token until

	 * we get H_SUCCESS. Aborting the retry loop before getting H_SUCCESS

	 * leave the system in an undefined state, so we wait.

	 */

	token = 0;



	do {

		rc = plpar_hcall(H_SCM_BIND_MEM, ret, p->drc_index, 0,

				p->blocks, BIND_ANY_ADDR, token);

		token = be64_to_cpu(ret[0]);

		cond_resched();

	} while (rc == H_BUSY);



	if (rc) {

		dev_err(&p->pdev->dev, "bind err: %lld\n", rc);

		return -ENXIO;

	}



	p->bound_addr = be64_to_cpu(ret[1]);



	dev_dbg(&p->pdev->dev, "bound drc %x to %pR\n", p->drc_index, &p->res);



	return 0;

}



static int drc_pmem_unbind(struct papr_scm_priv *p)

{

	unsigned long ret[PLPAR_HCALL_BUFSIZE];

	uint64_t rc, token;



	token = 0;



	/* NB: unbind has the same retry requirements mentioned above */

	do {

		rc = plpar_hcall(H_SCM_UNBIND_MEM, ret, p->drc_index,

				p->bound_addr, p->blocks, token);

		token = be64_to_cpu(ret);

		cond_resched();

	} while (rc == H_BUSY);



	if (rc)

		dev_err(&p->pdev->dev, "unbind error: %lld\n", rc);



	return !!rc;

}



static int papr_scm_meta_get(struct papr_scm_priv *p,

			struct nd_cmd_get_config_data_hdr *hdr)

{

	unsigned long data[PLPAR_HCALL_BUFSIZE];

	int64_t ret;



	if (hdr->in_offset >= p->metadata_size || hdr->in_length != 1)

		return -EINVAL;



	ret = plpar_hcall(H_SCM_READ_METADATA, data, p->drc_index,

			hdr->in_offset, 1);



	if (ret == H_PARAMETER) /* bad DRC index */

		return -ENODEV;

	if (ret)

		return -EINVAL; /* other invalid parameter */



	hdr->out_buf[0] = data[0] & 0xff;



	return 0;

}



static int papr_scm_meta_set(struct papr_scm_priv *p,

			struct nd_cmd_set_config_hdr *hdr)

{

	int64_t ret;



	if (hdr->in_offset >= p->metadata_size || hdr->in_length != 1)

		return -EINVAL;



	ret = plpar_hcall_norets(H_SCM_WRITE_METADATA,

			p->drc_index, hdr->in_offset, hdr->in_buf[0], 1);



	if (ret == H_PARAMETER) /* bad DRC index */

		return -ENODEV;

	if (ret)

		return -EINVAL; /* other invalid parameter */



	return 0;

}



int papr_scm_ndctl(struct nvdimm_bus_descriptor *nd_desc, struct nvdimm *nvdimm,

		unsigned int cmd, void *buf, unsigned int buf_len, int *cmd_rc)

{

	struct nd_cmd_get_config_size *get_size_hdr;

	struct papr_scm_priv *p;



	/* Only dimm-specific calls are supported atm */

	if (!nvdimm)

		return -EINVAL;



	p = nvdimm_provider_data(nvdimm);



	switch (cmd) {

	case ND_CMD_GET_CONFIG_SIZE:

		get_size_hdr = buf;



		get_size_hdr->status = 0;

		get_size_hdr->max_xfer = 1;

		get_size_hdr->config_size = p->metadata_size;

		*cmd_rc = 0;

		break;



	case ND_CMD_GET_CONFIG_DATA:

		*cmd_rc = papr_scm_meta_get(p, buf);

		break;



	case ND_CMD_SET_CONFIG_DATA:

		*cmd_rc = papr_scm_meta_set(p, buf);

		break;



	default:

		return -EINVAL;

	}



	dev_dbg(&p->pdev->dev, "returned with cmd_rc = %d\n", *cmd_rc);



	return 0;

}



static const struct attribute_group *region_attr_groups[] = {

	&nd_region_attribute_group,

	&nd_device_attribute_group,

	&nd_mapping_attribute_group,

	&nd_numa_attribute_group,

	NULL,

};



static const struct attribute_group *bus_attr_groups[] = {

	&nvdimm_bus_attribute_group,

	NULL,

};



static const struct attribute_group *papr_scm_dimm_groups[] = {

	&nvdimm_attribute_group,

	&nd_device_attribute_group,

	NULL,

};



static int papr_scm_nvdimm_init(struct papr_scm_priv *p)

{

	struct device *dev = &p->pdev->dev;

	struct nd_mapping_desc mapping;

	struct nd_region_desc ndr_desc;

	unsigned long dimm_flags;



	p->bus_desc.ndctl = papr_scm_ndctl;

	p->bus_desc.module = THIS_MODULE;

	p->bus_desc.of_node = p->pdev->dev.of_node;

	p->bus_desc.attr_groups = bus_attr_groups;

	p->bus_desc.provider_name = kstrdup(p->pdev->name, GFP_KERNEL);



	if (!p->bus_desc.provider_name)

		return -ENOMEM;



	p->bus = nvdimm_bus_register(NULL, &p->bus_desc);

	if (!p->bus) {

		dev_err(dev, "Error creating nvdimm bus %pOF\n", p->dn);

		return -ENXIO;

	}



	dimm_flags = 0;

	set_bit(NDD_ALIASING, &dimm_flags);



	p->nvdimm = nvdimm_create(p->bus, p, papr_scm_dimm_groups,

				dimm_flags, PAPR_SCM_DIMM_CMD_MASK, 0, NULL);

	if (!p->nvdimm) {

		dev_err(dev, "Error creating DIMM object for %pOF\n", p->dn);

		goto err;

	}



	/* now add the region */



	memset(&mapping, 0, sizeof(mapping));

	mapping.nvdimm = p->nvdimm;

	mapping.start = 0;

	mapping.size = p->blocks * p->block_size; // XXX: potential overflow?



	memset(&ndr_desc, 0, sizeof(ndr_desc));

	ndr_desc.attr_groups = region_attr_groups;

	ndr_desc.numa_node = dev_to_node(&p->pdev->dev);

	ndr_desc.res = &p->res;

	ndr_desc.of_node = p->dn;

	ndr_desc.provider_data = p;

	ndr_desc.mapping = &mapping;

	ndr_desc.num_mappings = 1;

	ndr_desc.nd_set = &p->nd_set;

	set_bit(ND_REGION_PAGEMAP, &ndr_desc.flags);



	p->region = nvdimm_pmem_region_create(p->bus, &ndr_desc);

	if (!p->region) {

		dev_err(dev, "Error registering region %pR from %pOF\n",

				ndr_desc.res, p->dn);

		goto err;

	}



	return 0;



err:	nvdimm_bus_unregister(p->bus);

	kfree(p->bus_desc.provider_name);

	return -ENXIO;

}



static int papr_scm_probe(struct platform_device *pdev)

{

	uint32_t drc_index, metadata_size, unit_cap[2];

	struct device_node *dn = pdev->dev.of_node;

	struct papr_scm_priv *p;

	int rc;



	/* check we have all the required DT properties */

	if (of_property_read_u32(dn, "ibm,my-drc-index", &drc_index)) {

		dev_err(&pdev->dev, "%pOF: missing drc-index!\n", dn);

		return -ENODEV;

	}



	if (of_property_read_u32_array(dn, "ibm,unit-capacity", unit_cap, 2)) {

		dev_err(&pdev->dev, "%pOF: missing unit-capacity!\n", dn);

		return -ENODEV;

	}



	p = kzalloc(sizeof(*p), GFP_KERNEL);

	if (!p)

		return -ENOMEM;



	/* optional DT properties */

	of_property_read_u32(dn, "ibm,metadata-size", &metadata_size);



	p->dn = dn;

	p->drc_index = drc_index;

	p->block_size = unit_cap[0];

	p->blocks     = unit_cap[1];



	/* might be zero */

	p->metadata_size = metadata_size;

	p->pdev = pdev;



	/* request the hypervisor to bind this region to somewhere in memory */

	rc = drc_pmem_bind(p);

	if (rc)

		goto err;



	/* setup the resource for the newly bound range */

	p->res.start = p->bound_addr;

	p->res.end   = p->bound_addr + p->blocks * p->block_size;

	p->res.name  = pdev->name;

	p->res.flags = IORESOURCE_MEM;



	rc = papr_scm_nvdimm_init(p);

	if (rc)

		goto err2;



	platform_set_drvdata(pdev, p);



	return 0;



err2:	drc_pmem_unbind(p);

err:	kfree(p);

	return rc;

}



static int papr_scm_remove(struct platform_device *pdev)

{

	struct papr_scm_priv *p = platform_get_drvdata(pdev);



	nvdimm_bus_unregister(p->bus);

	drc_pmem_unbind(p);

	kfree(p);



	return 0;

}



static const struct of_device_id papr_scm_match[] = {

	{ .compatible = "ibm,pmemory" },

	{ },

};



static struct platform_driver papr_scm_driver = {

	.probe = papr_scm_probe,

	.remove = papr_scm_remove,

	.driver = {

		.name = "papr_scm",

		.owner = THIS_MODULE,

		.of_match_table = papr_scm_match,

	},

};



module_platform_driver(papr_scm_driver);

MODULE_DEVICE_TABLE(of, papr_scm_match);

MODULE_LICENSE("GPL");

MODULE_AUTHOR("IBM Corporation");