On Wed, 2020-02-26 at 16:07 +1100, Andrew Donnellan wrote: > On 21/2/20 2:27 pm, Alastair D'Silva wrote: > > From: Alastair D'Silva <alastair@xxxxxxxxxxx> > > > > This driver exposes LPC memory on OpenCAPI pmem cards > > as an NVDIMM, allowing the existing nvram infrastructure > > to be used. > > > > Namespace metadata is stored on the media itself, so > > scm_reserve_metadata() maps 1 section's worth of PMEM storage > > at the start to hold this. The rest of the PMEM range is registered > > with libnvdimm as an nvdimm. scm_ndctl_config_read/write/size() > > provide > > callbacks to libnvdimm to access the metadata. > > > > Signed-off-by: Alastair D'Silva <alastair@xxxxxxxxxxx> > > I'm not particularly familiar with the nvdimm subsystem, so the scope > of > my review is more on the ocxl + misc issues side. > > A few minor checkpatch warnings that don't matter all that much: > > https://openpower.xyz/job/snowpatch/job/snowpatch-linux-checkpatch/11786//artifact/linux/checkpatch.log > > A few other comments below. > > > diff --git a/arch/powerpc/platforms/powernv/pmem/ocxl.c > > b/arch/powerpc/platforms/powernv/pmem/ocxl.c > > new file mode 100644 > > index 000000000000..3c4eeb5dcc0f > > --- /dev/null > > +++ b/arch/powerpc/platforms/powernv/pmem/ocxl.c > > @@ -0,0 +1,473 @@ > > +// SPDX-License-Id > > +// Copyright 2019 IBM Corp. > > + > > +/* > > + * A driver for OpenCAPI devices that implement the Storage Class > > + * Memory specification. > > + */ > > + > > +#include <linux/module.h> > > +#include <misc/ocxl.h> > > +#include <linux/ndctl.h> > > +#include <linux/mm_types.h> > > +#include <linux/memory_hotplug.h> > > +#include "ocxl_internal.h" > > + > > + > > +static const struct pci_device_id ocxlpmem_pci_tbl[] = { > > + { PCI_DEVICE(PCI_VENDOR_ID_IBM, 0x0625), }, > > + { } > > +}; > > + > > +MODULE_DEVICE_TABLE(pci, ocxlpmem_pci_tbl); > > + > > +#define NUM_MINORS 256 // Total to reserve > > + > > +static dev_t ocxlpmem_dev; > > +static struct class *ocxlpmem_class; > > +static struct mutex minors_idr_lock; > > +static struct idr minors_idr; > > + > > +/** > > + * ndctl_config_write() - Handle a ND_CMD_SET_CONFIG_DATA command > > from ndctl > > + * @ocxlpmem: the device metadata > > + * @command: the incoming data to write > > + * Return: 0 on success, negative on failure > > + */ > > +static int ndctl_config_write(struct ocxlpmem *ocxlpmem, > > + struct nd_cmd_set_config_hdr *command) > > +{ > > + if (command->in_offset + command->in_length > LABEL_AREA_SIZE) > > + return -EINVAL; > > + > > + memcpy_flushcache(ocxlpmem->metadata_addr + command->in_offset, > > command->in_buf, > > + command->in_length); > > Out of scope for this patch - given that we use memcpy_mcsafe in the > config read, does it make sense to change memcpy_flushcache to be > mcsafe > as well? > Aneesh has confirmed that stores don't generate machine checks. > > + > > + return 0; > > +} > > + > > +/** > > + * ndctl_config_read() - Handle a ND_CMD_GET_CONFIG_DATA command > > from ndctl > > + * @ocxlpmem: the device metadata > > + * @command: the read request > > + * Return: 0 on success, negative on failure > > + */ > > +static int ndctl_config_read(struct ocxlpmem *ocxlpmem, > > + struct nd_cmd_get_config_data_hdr > > *command) > > +{ > > + if (command->in_offset + command->in_length > LABEL_AREA_SIZE) > > + return -EINVAL; > > + > > + memcpy_mcsafe(command->out_buf, ocxlpmem->metadata_addr + > > command->in_offset, > > + command->in_length); > > + > > + return 0; > > +} > > + > > +/** > > + * ndctl_config_size() - Handle a ND_CMD_GET_CONFIG_SIZE command > > from ndctl > > + * @command: the read request > > + * Return: 0 on success, negative on failure > > + */ > > +static int ndctl_config_size(struct nd_cmd_get_config_size > > *command) > > +{ > > + command->status = 0; > > + command->config_size = LABEL_AREA_SIZE; > > + command->max_xfer = PAGE_SIZE; > > + > > + return 0; > > +} > > + > > +static int ndctl(struct nvdimm_bus_descriptor *nd_desc, > > + struct nvdimm *nvdimm, > > + unsigned int cmd, void *buf, unsigned int buf_len, int > > *cmd_rc) > > +{ > > + struct ocxlpmem *ocxlpmem = container_of(nd_desc, struct > > ocxlpmem, bus_desc); > > + > > + switch (cmd) { > > + case ND_CMD_GET_CONFIG_SIZE: > > + *cmd_rc = ndctl_config_size(buf); > > + return 0; > > + > > + case ND_CMD_GET_CONFIG_DATA: > > + *cmd_rc = ndctl_config_read(ocxlpmem, buf); > > + return 0; > > + > > + case ND_CMD_SET_CONFIG_DATA: > > + *cmd_rc = ndctl_config_write(ocxlpmem, buf); > > + return 0; > > + > > + default: > > + return -ENOTTY; > > + } > > +} > > + > > +/** > > + * reserve_metadata() - Reserve space for nvdimm metadata > > + * @ocxlpmem: the device metadata > > + * @lpc_mem: The resource representing the LPC memory of the > > OpenCAPI device > > + */ > > +static int reserve_metadata(struct ocxlpmem *ocxlpmem, > > + struct resource *lpc_mem) > > +{ > > + ocxlpmem->metadata_addr = devm_memremap(&ocxlpmem->dev, > > lpc_mem->start, > > + LABEL_AREA_SIZE, > > MEMREMAP_WB); > > + if (IS_ERR(ocxlpmem->metadata_addr)) > > + return PTR_ERR(ocxlpmem->metadata_addr); > > + > > + return 0; > > +} > > + > > +/** > > + * register_lpc_mem() - Discover persistent memory on a device and > > register it with the NVDIMM subsystem > > + * @ocxlpmem: the device metadata > > + * Return: 0 on success > > + */ > > +static int register_lpc_mem(struct ocxlpmem *ocxlpmem) > > +{ > > + struct nd_region_desc region_desc; > > + struct nd_mapping_desc nd_mapping_desc; > > + struct resource *lpc_mem; > > + const struct ocxl_afu_config *config; > > + const struct ocxl_fn_config *fn_config; > > + int rc; > > + unsigned long nvdimm_cmd_mask = 0; > > + unsigned long nvdimm_flags = 0; > > + int target_node; > > + char serial[16+1]; > > inb4 mpe tells you to Reverse Christmas Tree > -1, petty :P > > + > > + // Set up the reserved metadata area > > + rc = ocxl_afu_map_lpc_mem(ocxlpmem->ocxl_afu); > > + if (rc < 0) > > + return rc; > > + > > + lpc_mem = ocxl_afu_lpc_mem(ocxlpmem->ocxl_afu); > > + if (lpc_mem == NULL || lpc_mem->start == 0) > > + return -EINVAL; > > + > > + config = ocxl_afu_config(ocxlpmem->ocxl_afu); > > + fn_config = ocxl_function_config(ocxlpmem->ocxl_fn); > > + > > + rc = reserve_metadata(ocxlpmem, lpc_mem); > > + if (rc) > > + return rc; > > + > > + ocxlpmem->bus_desc.provider_name = "ocxl-pmem"; > > + ocxlpmem->bus_desc.ndctl = ndctl; > > + ocxlpmem->bus_desc.module = THIS_MODULE; > > + > > + ocxlpmem->nvdimm_bus = nvdimm_bus_register(&ocxlpmem->dev, > > + &ocxlpmem- > > >bus_desc); > > + if (!ocxlpmem->nvdimm_bus) > > + return -EINVAL; > > + > > + ocxlpmem->pmem_res.start = (u64)lpc_mem->start + > > LABEL_AREA_SIZE; > > + ocxlpmem->pmem_res.end = (u64)lpc_mem->start + config- > > >lpc_mem_size - 1; > > + ocxlpmem->pmem_res.name = "OpenCAPI persistent memory"; > > + > > + set_bit(ND_CMD_GET_CONFIG_SIZE, &nvdimm_cmd_mask); > > + set_bit(ND_CMD_GET_CONFIG_DATA, &nvdimm_cmd_mask); > > + set_bit(ND_CMD_SET_CONFIG_DATA, &nvdimm_cmd_mask); > > + > > + set_bit(NDD_ALIASING, &nvdimm_flags); > > + > > + snprintf(serial, sizeof(serial), "%llx", fn_config->serial); > > + nd_mapping_desc.nvdimm = nvdimm_create(ocxlpmem->nvdimm_bus, > > ocxlpmem, > > + NULL, nvdimm_flags, nvdimm_cmd_mask, > > + 0, NULL); > > + if (!nd_mapping_desc.nvdimm) > > + return -ENOMEM; > > + > > + if (nvdimm_bus_check_dimm_count(ocxlpmem->nvdimm_bus, 1)) > > + return -EINVAL; > > + > > + nd_mapping_desc.start = ocxlpmem->pmem_res.start; > > + nd_mapping_desc.size = resource_size(&ocxlpmem->pmem_res); > > + nd_mapping_desc.position = 0; > > + > > + ocxlpmem->nd_set.cookie1 = fn_config->serial + 1; // allow for > > empty serial > > + ocxlpmem->nd_set.cookie2 = fn_config->serial + 1; > > + > > + target_node = of_node_to_nid(ocxlpmem->pdev->dev.of_node); > > + > > + memset(®ion_desc, 0, sizeof(region_desc)); > > + region_desc.res = &ocxlpmem->pmem_res; > > + region_desc.numa_node = NUMA_NO_NODE; > > + region_desc.target_node = target_node; > > + region_desc.num_mappings = 1; > > + region_desc.mapping = &nd_mapping_desc; > > + region_desc.nd_set = &ocxlpmem->nd_set; > > + > > + set_bit(ND_REGION_PAGEMAP, ®ion_desc.flags); > > + /* > > + * NB: libnvdimm copies the data from ndr_desc into it's own > > + * structures so passing a stack pointer is fine. > > + */ > > + ocxlpmem->nd_region = nvdimm_pmem_region_create(ocxlpmem- > > >nvdimm_bus, > > + ®ion_desc); > > + if (!ocxlpmem->nd_region) > > + return -EINVAL; > > + > > + dev_info(&ocxlpmem->dev, > > + "Onlining %lluMB of persistent memory\n", > > + nd_mapping_desc.size / SZ_1M); > > + > > + return 0; > > +} > > + > > +/** > > + * allocate_minor() - Allocate a minor number to use for an > > OpenCAPI pmem device > > + * @ocxlpmem: the device metadata > > + * Return: the allocated minor number > > + */ > > +static int allocate_minor(struct ocxlpmem *ocxlpmem) > > +{ > > + int minor; > > + > > + mutex_lock(&minors_idr_lock); > > + minor = idr_alloc(&minors_idr, ocxlpmem, 0, NUM_MINORS, > > GFP_KERNEL); > > + mutex_unlock(&minors_idr_lock); > > + return minor; > > +} > > + > > +static void free_minor(struct ocxlpmem *ocxlpmem) > > The lack of a kerneldoc comment here is inconsistent :) > > > +{ > > + mutex_lock(&minors_idr_lock); > > + idr_remove(&minors_idr, MINOR(ocxlpmem->dev.devt)); > > + mutex_unlock(&minors_idr_lock); > > +} > > + > > +/** > > + * free_ocxlpmem() - Free all members of an ocxlpmem struct > > + * @ocxlpmem: the device struct to clear > > + */ > > +static void free_ocxlpmem(struct ocxlpmem *ocxlpmem) > > +{ > > + int rc; > > + > > + if (ocxlpmem->nvdimm_bus) > > + nvdimm_bus_unregister(ocxlpmem->nvdimm_bus); > > + > > + free_minor(ocxlpmem); > > + > > + if (ocxlpmem->metadata_addr) > > + devm_memunmap(&ocxlpmem->dev, ocxlpmem->metadata_addr); > > + > > + if (ocxlpmem->ocxl_context) { > > + rc = ocxl_context_detach(ocxlpmem->ocxl_context); > > + if (rc == -EBUSY) > > + dev_warn(&ocxlpmem->dev, "Timeout detaching > > ocxl context\n"); > > + else > > + ocxl_context_free(ocxlpmem->ocxl_context); > > + > > + } > > + > > + if (ocxlpmem->ocxl_afu) > > + ocxl_afu_put(ocxlpmem->ocxl_afu); > > + > > + if (ocxlpmem->ocxl_fn) > > + ocxl_function_close(ocxlpmem->ocxl_fn); > > + > > + kfree(ocxlpmem); > > +} > > + > > +/** > > + * free_ocxlpmem_dev() - Free an OpenCAPI persistent memory device > > + * @dev: The device struct > > + */ > > +static void free_ocxlpmem_dev(struct device *dev) > > +{ > > + struct ocxlpmem *ocxlpmem = container_of(dev, struct ocxlpmem, > > dev); > > + > > + free_ocxlpmem(ocxlpmem); > > +} > > + > > +/** > > + * ocxlpmem_register() - Register an OpenCAPI pmem device with the > > kernel > > + * @ocxlpmem: the device metadata > > + * Return: 0 on success, negative on failure > > + */ > > +static int ocxlpmem_register(struct ocxlpmem *ocxlpmem) > > +{ > > + int rc; > > + int minor = allocate_minor(ocxlpmem); > > + > > + if (minor < 0) > > + return minor; > > + > > + ocxlpmem->dev.release = free_ocxlpmem_dev; > > + rc = dev_set_name(&ocxlpmem->dev, "ocxlpmem%d", minor); > > + if (rc < 0) > > + return rc; > > + > > + ocxlpmem->dev.devt = MKDEV(MAJOR(ocxlpmem_dev), minor); > > + ocxlpmem->dev.class = ocxlpmem_class; > > + ocxlpmem->dev.parent = &ocxlpmem->pdev->dev; > > + > > + return device_register(&ocxlpmem->dev); > > +} > > + > > +/** > > + * ocxlpmem_remove() - Free an OpenCAPI persistent memory device > > + * @pdev: the PCI device information struct > > + */ > > +static void ocxlpmem_remove(struct pci_dev *pdev) > > +{ > > + if (PCI_FUNC(pdev->devfn) == 0) { > > + struct ocxlpmem_function0 *func0 = > > pci_get_drvdata(pdev); > > + > > + if (func0) { > > + ocxl_function_close(func0->ocxl_fn); > > + func0->ocxl_fn = NULL; > > + } > > + } else { > > + struct ocxlpmem *ocxlpmem = pci_get_drvdata(pdev); > > + > > + if (ocxlpmem) > > + device_unregister(&ocxlpmem->dev); > > + } > > +} > > + > > +/** > > + * probe_function0() - Set up function 0 for an OpenCAPI > > persistent memory device > > + * This is important as it enables templates higher than 0 across > > all other functions, > > + * which in turn enables higher bandwidth accesses > > + * @pdev: the PCI device information struct > > + * Return: 0 on success, negative on failure > > + */ > > +static int probe_function0(struct pci_dev *pdev) > > +{ > > + struct ocxlpmem_function0 *func0 = NULL; > > + struct ocxl_fn *fn; > > + > > + func0 = kzalloc(sizeof(*func0), GFP_KERNEL); > > + if (!func0) > > + return -ENOMEM; > > + > > + func0->pdev = pdev; > > + fn = ocxl_function_open(pdev); > > + if (IS_ERR(fn)) { > > + kfree(func0); > > + dev_err(&pdev->dev, "failed to open OCXL function\n"); > > + return PTR_ERR(fn); > > + } > > + func0->ocxl_fn = fn; > > + > > + pci_set_drvdata(pdev, func0); > > + > > + return 0; > > +} > > + > > +/** > > + * probe() - Init an OpenCAPI persistent memory device > > + * @pdev: the PCI device information struct > > + * @ent: The entry from ocxlpmem_pci_tbl > > + * Return: 0 on success, negative on failure > > + */ > > +static int probe(struct pci_dev *pdev, const struct pci_device_id > > *ent) > > +{ > > + struct ocxlpmem *ocxlpmem; > > + int rc; > > + > > + if (PCI_FUNC(pdev->devfn) == 0) > > + return probe_function0(pdev); > > + else if (PCI_FUNC(pdev->devfn) != 1) > > + return 0; > > + > > + ocxlpmem = kzalloc(sizeof(*ocxlpmem), GFP_KERNEL); > > + if (!ocxlpmem) { > > + dev_err(&pdev->dev, "Could not allocate OpenCAPI > > persistent memory metadata\n"); > > + rc = -ENOMEM; > > + goto err; > > + } > > + ocxlpmem->pdev = pdev; > > + > > + pci_set_drvdata(pdev, ocxlpmem); > > + > > + ocxlpmem->ocxl_fn = ocxl_function_open(pdev); > > + if (IS_ERR(ocxlpmem->ocxl_fn)) { > > + kfree(ocxlpmem); > > You can't free this yet... Whoops > > > + pci_set_drvdata(pdev, NULL); > > + dev_err(&pdev->dev, "failed to open OCXL function\n"); > > + rc = PTR_ERR(ocxlpmem->ocxl_fn); > > + goto err; > > + } > > + > > + ocxlpmem->ocxl_afu = ocxl_function_fetch_afu(ocxlpmem->ocxl_fn, > > 0); > > + if (ocxlpmem->ocxl_afu == NULL) { > > + dev_err(&pdev->dev, "Could not get OCXL AFU from > > function\n"); > > + rc = -ENXIO; > > + goto err; > > Meanwhile in this case, I think ocxlpmem and ocxlpmem->ocxl_fn get > leaked (it's before ocxlpmem_register(), so the cleanup handler > hasn't > been registered). > > Add some new error labels for these two paths? > Ok > > + } > > + > > + ocxl_afu_get(ocxlpmem->ocxl_afu); > > + > > + // Resources allocated below here are cleaned up in the release > > handler > > + > > + rc = ocxlpmem_register(ocxlpmem); > > + if (rc) { > > + dev_err(&pdev->dev, "Could not register OpenCAPI > > persistent memory device with the kernel\n"); > > + goto err; > > + } > > + > > + rc = ocxl_context_alloc(&ocxlpmem->ocxl_context, ocxlpmem- > > >ocxl_afu, NULL); > > + if (rc) { > > + dev_err(&pdev->dev, "Could not allocate OCXL > > context\n"); > > + goto err; > > + } > > + > > + rc = ocxl_context_attach(ocxlpmem->ocxl_context, 0, NULL); > > + if (rc) { > > + dev_err(&pdev->dev, "Could not attach ocxl context\n"); > > + goto err; > > + } > > + > > + rc = register_lpc_mem(ocxlpmem); > > + if (rc) { > > + dev_err(&pdev->dev, "Could not register OpenCAPI > > persistent memory with libnvdimm\n"); > > + goto err; > > + } > > + > > + return 0; > > + > > +err: > > + /* > > + * Further cleanup is done in the release handler via > > free_ocxlpmem() > > + * This allows us to keep the character device live to handle > > IOCTLs to > > + * investigate issues if the card has an error > > + */ > > + > > + dev_err(&pdev->dev, > > + "Error detected, will not register OpenCAPI persistent > > memory\n"); > > + return rc; > > +} > > + > > +static struct pci_driver pci_driver = { > > + .name = "ocxl-pmem", > > + .id_table = ocxlpmem_pci_tbl, > > + .probe = probe, > > + .remove = ocxlpmem_remove, > > + .shutdown = ocxlpmem_remove, > > +}; > > + > > +static int __init ocxlpmem_init(void) > > +{ > > + int rc = 0; > > + > > + rc = pci_register_driver(&pci_driver); > > + if (rc) > > + return rc; > > + > > + return 0; > > +} > > + > > +static void ocxlpmem_exit(void) > > +{ > > + pci_unregister_driver(&pci_driver); > > +} > > + > > +module_init(ocxlpmem_init); > > +module_exit(ocxlpmem_exit); > > + > > +MODULE_DESCRIPTION("OpenCAPI Persistent Memory"); > > +MODULE_LICENSE("GPL"); > > diff --git a/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h > > b/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h > > new file mode 100644 > > index 000000000000..0faf3740e9b8 > > --- /dev/null > > +++ b/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h > > @@ -0,0 +1,28 @@ > > +// SPDX-License-Identifier: GPL-2.0+ > > +// Copyright 2019 IBM Corp. > > + > > +#include <linux/pci.h> > > +#include <misc/ocxl.h> > > +#include <linux/libnvdimm.h> > > +#include <linux/mm.h> > > + > > +#define LABEL_AREA_SIZE (1UL << PA_SECTION_SHIFT) > > + > > +struct ocxlpmem_function0 { > > + struct pci_dev *pdev; > > + struct ocxl_fn *ocxl_fn; > > +}; > > Hmm, given this struct serves no purpose other than associating an > ocxl_fn with a pci_dev, and special handling for function 0 is > probably > going to be a common pattern in ocxl dependent drivers, perhaps we > should export a function from ocxl that converts ocxl_fn -> pci_dev, > and > then you can just point the drvdata straight at the ocxl_fn? > Yup, the struct is vestigial, I'll remove it and deal directly with the ocxl_fn instead. > > > + > > +struct ocxlpmem { > > + struct device dev; > > + struct pci_dev *pdev; > > + struct ocxl_fn *ocxl_fn; > > + struct nd_interleave_set nd_set; > > + struct nvdimm_bus_descriptor bus_desc; > > + struct nvdimm_bus *nvdimm_bus; > > + struct ocxl_afu *ocxl_afu; > > + struct ocxl_context *ocxl_context; > > + void *metadata_addr; > > + struct resource pmem_res; > > + struct nd_region *nd_region; > > +}; > > -- Alastair D'Silva Open Source Developer Linux Technology Centre, IBM Australia mob: 0423 762 819
