On Fri, 15 Mar 2024, Russ Weight wrote:
On Fri, Mar 08, 2024 at 09:23:27AM -0800, Matthew Gerlach wrote:From: Tim Whisonant <tim.whisonant@xxxxxxxxx> Add a Device Feature List (DFL) driver for the Intel CXL Cache IP block. The driver provides a means of accessing the device MMIO and the capability to pin buffers and program their physical addresses into the HE-Cache registers. User interface is exposed via /dev/dfl-cxl-cache.X as described in include/uapi/linux/fpga-dfl.h. Signed-off-by: Tim Whisonant <tim.whisonant@xxxxxxxxx> Co-developed-by: Ananda Ravuri <ananda.ravuri@xxxxxxxxx> Signed-off-by: Ananda Ravuri <ananda.ravuri@xxxxxxxxx> Signed-off-by: Matthew Gerlach <matthew.gerlach@xxxxxxxxxxxxxxx> --- drivers/fpga/Kconfig | 11 + drivers/fpga/Makefile | 1 + drivers/fpga/dfl-cxl-cache.c | 645 ++++++++++++++++++++++++++++++++++ include/uapi/linux/fpga-dfl.h | 98 ++++++ 4 files changed, 755 insertions(+) create mode 100644 drivers/fpga/dfl-cxl-cache.c diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig index 2f689ac4ba3a..00931a3deebf 100644 --- a/drivers/fpga/Kconfig +++ b/drivers/fpga/Kconfig @@ -257,6 +257,17 @@ config FPGA_M10_BMC_SEC_UPDATE (BMC) and provides support for secure updates for the BMC image, the FPGA image, the Root Entry Hashes, etc. +config FPGA_DFL_CXL_CACHE + tristate "Intel CXL cache driver"The name implies a large scope. If it is not intended to be generally used by all Intel devices that support CXL cache, then a more narrow/specific name might be better.
Actually this driver code is specific the R-Tile Hard IP in particularAgilex chips with corresponding CXL IP in the FPGA; so, I agree that a more narrow/specific name would be better.
+ depends on DRM && FPGA_DFL + help + This is the driver for CXL cache Accelerated Function Unit + (AFU) which configures the IP and provides DMA buffer management + to user space. + + To compile this driver as a module, chose M here: the + module will be called dfl_cxl_cache. + config FPGA_MGR_MICROCHIP_SPI tristate "Microchip Polarfire SPI FPGA manager" depends on SPI diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile index 352a2612623e..970902810845 100644 --- a/drivers/fpga/Makefile +++ b/drivers/fpga/Makefile @@ -55,6 +55,7 @@ obj-$(CONFIG_FPGA_DFL_NIOS_INTEL_PAC_N3000) += dfl-n3000-nios.o # Drivers for FPGAs which implement DFL obj-$(CONFIG_FPGA_DFL_PCI) += dfl-pci.o +obj-$(CONFIG_FPGA_DFL_CXL_CACHE) += dfl-cxl-cache.o # KUnit tests obj-$(CONFIG_FPGA_KUNIT_TESTS) += tests/ diff --git a/drivers/fpga/dfl-cxl-cache.c b/drivers/fpga/dfl-cxl-cache.c new file mode 100644 index 000000000000..ee2ae04ac058 --- /dev/null +++ b/drivers/fpga/dfl-cxl-cache.c @@ -0,0 +1,645 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * DFL device driver for Host Exerciser Cache private feature. + * + * Provides a means of accessing the device MMIO and the + * capability to pin buffers and program their physical + * addresses into the HE-Cache registers. User interface + * is exposed via /dev/dfl-cxl-cache.X as described in + * include/uapi/linux/fpga-dfl.h. + * + * Copyright (C) 2023 Intel Corporation, Inc. + * + * Authors: + * Tim Whisonant <tim.whisonant@xxxxxxxxx> + * Ananda Ravuri <ananda.ravuri@xxxxxxxxx> + */ + +#include <linux/bitfield.h> +#include <linux/cdev.h> +#include <linux/cleanup.h> +#include <linux/container_of.h> +#include <linux/dfl.h> +#include <linux/errno.h> +#include <linux/fpga-dfl.h> +#include <linux/highmem.h> +#include <linux/io.h> +#include <linux/mmap_lock.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/pgtable.h> +#include <linux/slab.h> +#include <linux/spinlock.h> +#include <linux/types.h> + +#include <drm/drm_cache.h> + +#define DFL_CXL_CACHE_DRIVER_NAME "dfl-cxl-cache" +#define FME_FEATURE_ID_CXL_CACHE 0x25 + +struct dfl_cxl_cache_buffer_region { + struct rb_node node; + u32 flags; + u64 user_addr; + u64 length; + struct page **pages; + phys_addr_t phys; + u64 offset[DFL_ARRAY_MAX_SIZE]; +}; + +struct dfl_cxl_cache { + struct cdev cdev; + struct dfl_device *ddev; + int id; + struct device *dev; + atomic_t opened; + void __iomem *mmio_base; + int mmio_size; + struct dfl_cxl_cache_region_info rinfo; + struct rb_root dma_regions; +}; + +static DEFINE_MUTEX(dfl_cxl_cache_class_lock); +static struct class *dfl_cxl_cache_class; +static dev_t dfl_cxl_cache_devt; +static int dfl_cxl_cache_devices; + +static int dfl_cxl_cache_open(struct inode *inode, struct file *filp) +{ + struct dfl_cxl_cache *cxl_cache = container_of(inode->i_cdev, struct dfl_cxl_cache, cdev); + + if (atomic_cmpxchg(&cxl_cache->opened, 0, 1)) + return -EBUSY; + + filp->private_data = cxl_cache; + + return 0; +} + +static long cxl_cache_ioctl_check_extension(struct dfl_cxl_cache *cxl_cache, unsigned long arg) +{ + /* No extension support for now */ + return 0; +} + +static long cxl_cache_ioctl_get_region_info(struct dfl_cxl_cache *cxl_cache, void __user *arg) +{ + struct dfl_cxl_cache_region_info rinfo; + unsigned long minsz; + + minsz = offsetofend(struct dfl_cxl_cache_region_info, offset); + if (copy_from_user(&rinfo, arg, minsz)) + return -EFAULT; + + if (rinfo.argsz < minsz) + return -EINVAL; + + rinfo.flags = cxl_cache->rinfo.flags; + rinfo.size = cxl_cache->rinfo.size; + rinfo.offset = cxl_cache->rinfo.offset; + + if (copy_to_user(arg, &rinfo, sizeof(rinfo))) + return -EFAULT; + + return 0; +} + +static void cxl_cache_unpin_pages(struct device *dev, struct page ***pages, unsigned long length) +{ + const long npages = PFN_DOWN(length); + + if (!*pages) + return; + + unpin_user_pages(*pages, npages); + kfree(*pages); + *pages = NULL; + account_locked_vm(current->mm, npages, false); +} + +static bool cxl_cache_check_continuous_pages(struct page **pages, unsigned long length) +{ + int i; + const int npages = PFN_DOWN(length); + + for (i = 0; i < npages - 1; i++) + if (page_to_pfn(pages[i]) + 1 != page_to_pfn(pages[i + 1])) + return false; + + return true; +} + +static int cxl_cache_dma_pin_pages(struct dfl_cxl_cache *cxl_cache, + struct dfl_cxl_cache_buffer_region *region) +{ + int ret, pinned; + unsigned int flags = FOLL_LONGTERM; + const int npages = PFN_DOWN(region->length); + + ret = account_locked_vm(current->mm, npages, true); + if (ret) { + dev_err(cxl_cache->dev, "account_locked_vm() failed: %d\n", ret); + return ret; + } + + region->pages = kcalloc(npages, sizeof(struct page *), GFP_KERNEL); + if (!region->pages) { + ret = -ENOMEM; + goto unlock_vm; + } + + if (region->flags & DFL_CXL_BUFFER_MAP_WRITABLE) + flags |= FOLL_WRITE; + + pinned = pin_user_pages_fast(region->user_addr, npages, flags, region->pages); + if (pinned == npages) + return 0; + + ret = -EFAULT; + if (pinned > 0) + unpin_user_pages(region->pages, pinned); + + kfree(region->pages); +unlock_vm: + account_locked_vm(current->mm, npages, false); + return ret; +} + +static void cxl_cache_dma_region_remove(struct dfl_cxl_cache *cxl_cache, + struct dfl_cxl_cache_buffer_region *region) +{ + rb_erase(®ion->node, &cxl_cache->dma_regions); +} + +static bool dma_region_check_user_addr(struct dfl_cxl_cache_buffer_region *region, u64 user_addr, + u64 size) +{ + if (!size && region->user_addr != user_addr) + return false;So, if size == 0, that is okay as long as (region->user_addr == user_addr)?
Yes, that is the intent.
+ + return (region->user_addr <= user_addr) && + (region->length + region->user_addr >= user_addr + size);Do you need to worry about overflow when adding (user_addr + size)? These values come from the user, right?
The values from the user are checked for overflow in cxl_cache_ioctl_numa_buffer_map(). For consistency, checking for overflow should also be checked in cxl_cache_ioctl_numa_buffer_unmap(),
+} + +static struct dfl_cxl_cache_buffer_region* +cxl_cache_dma_region_find(struct dfl_cxl_cache *cxl_cache, u64 user_addr, u64 size) +{ + struct rb_node *node = cxl_cache->dma_regions.rb_node; + + while (node) { + struct dfl_cxl_cache_buffer_region *region; + + region = container_of(node, struct dfl_cxl_cache_buffer_region, node); + + if (dma_region_check_user_addr(region, user_addr, size)) + return region; + + if (user_addr < region->user_addr) + node = node->rb_left; + else if (user_addr > region->user_addr) + node = node->rb_right; + else + break; + } + + return NULL; +} + +static int cxl_cache_dma_region_add(struct dfl_cxl_cache *cxl_cache, + struct dfl_cxl_cache_buffer_region *region) +{ + struct rb_node **new, *parent = NULL; + + new = &cxl_cache->dma_regions.rb_node; + + while (*new) { + struct dfl_cxl_cache_buffer_region *this; + + this = container_of(*new, struct dfl_cxl_cache_buffer_region, node); + parent = *new; + + if (dma_region_check_user_addr(this, region->user_addr, region->length)) + return -EEXIST; + + if (region->user_addr < this->user_addr) + new = &((*new)->rb_left); + else if (region->user_addr > this->user_addr) + new = &((*new)->rb_right); + else + return -EEXIST; + } + + rb_link_node(®ion->node, parent, new); + rb_insert_color(®ion->node, &cxl_cache->dma_regions); + + return 0; +} + +static void fixup_ptes(struct mm_struct *mm, unsigned long start, unsigned long end) +{ + unsigned long addr; + pgd_t *pgd; + p4d_t *p4d; + pud_t *pud; + pmd_t *pmd; + pte_t *pte; + + for (addr = start; addr < end; addr += PAGE_SIZE) { + pgd = pgd_offset(mm, addr); + if (pgd_bad(*pgd) || pgd_none(*pgd)) + continue; + + p4d = p4d_offset(pgd, addr); + if (p4d_bad(*p4d) || p4d_none(*p4d)) + continue; + + pud = pud_offset(p4d, addr); + if (pud_bad(*pud) || pud_none(*pud)) + continue; + + pmd = pmd_offset(pud, addr); + if (pmd_bad(*pmd) || pmd_none(*pmd)) + continue; + + pte = pte_offset_kernel(pmd, addr); + if (!pte_none(*pte) && pte_present(*pte)) + *pte = pte_wrprotect(*pte); + } +} + +static long cxl_cache_set_region_read_only(struct dfl_cxl_cache *cxl_cache, + struct dfl_cxl_cache_buffer_region *region) +{ + struct vm_area_struct *vma; + long ret = 0; + + vma = vma_lookup(current->mm, region->user_addr); + if (IS_ERR(vma)) { + ret = PTR_ERR(vma); + dev_err(cxl_cache->dev, "vma_lookup() failed: %ld\n", ret); + return ret; + } + + mmap_write_lock(current->mm); + + /* Mark the pages as non-cached and write-protected. */ + vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); + vm_flags_clear(vma, VM_WRITE); + + fixup_ptes(current->mm, vma->vm_start, vma->vm_end); + + mmap_write_unlock(current->mm); + + /* Flush all remaining cache entries. */ + drm_clflush_virt_range(page_address(region->pages[0]), region->length); + + return ret; +} + +static long cxl_cache_ioctl_numa_buffer_map(struct dfl_cxl_cache *cxl_cache, void __user *arg) +{ + int i = 0; + unsigned long minsz = 0; + long ret = 0; + struct dfl_cxl_cache_buffer_map dma_map; + struct dfl_cxl_cache_buffer_region *region; + + minsz = offsetofend(struct dfl_cxl_cache_buffer_map, csr_array); + if (copy_from_user(&dma_map, arg, minsz)) { + dev_err(cxl_cache->dev, "fails to copy from user space buffer\n"); + return -EFAULT; + } + if (dma_map.argsz < minsz) { + dev_err(cxl_cache->dev, "invalid ioctl buffer size\n"); + return -EINVAL; + } + + /* Check Inputs, only accept page-aligned user memory region with valid length */ + if (!PAGE_ALIGNED(dma_map.user_addr) || !PAGE_ALIGNED(dma_map.length) || + !(dma_map.length)) { + dev_err(cxl_cache->dev, "length is not page-aligned or the length is zero\n"); + return -EINVAL; + } + + /* Check overflow */ + if (dma_map.user_addr + dma_map.length < dma_map.user_addr) { + dev_err(cxl_cache->dev, "dma buffer check overflow\n"); + return -EINVAL; + } + + region = kzalloc(sizeof(*region), GFP_KERNEL); + if (!region) + return -ENOMEM; + + region->flags = dma_map.flags; + region->user_addr = dma_map.user_addr; + region->length = dma_map.length; + + /* Pin the user memory region */ + ret = cxl_cache_dma_pin_pages(cxl_cache, region); + if (ret) { + dev_err(cxl_cache->dev, "failed to pin pages\n"); + goto free_region; + } + + /* Only accept continuous pages, return error else */ + if (!cxl_cache_check_continuous_pages(region->pages, region->length)) { + dev_err(cxl_cache->dev, "pages are not continuous\n"); + ret = -EINVAL; + goto out_unpin_pages; + } + + if (!(region->flags & DFL_CXL_BUFFER_MAP_WRITABLE)) { + ret = cxl_cache_set_region_read_only(cxl_cache, region); + if (ret) + goto out_unpin_pages; + } + + ret = cxl_cache_dma_region_add(cxl_cache, region); + if (ret) { + dev_err(cxl_cache->dev, "failed to add dma region\n"); + goto out_unpin_pages; + } + + region->phys = page_to_phys(region->pages[0]); + + for (i = 0; i < DFL_ARRAY_MAX_SIZE; i++) { + if (dma_map.csr_array[i] && dma_map.csr_array[i] < cxl_cache->rinfo.size) + writeq(region->phys, cxl_cache->mmio_base + dma_map.csr_array[i]); + } + + return 0; + +out_unpin_pages: + cxl_cache_unpin_pages(cxl_cache->dev, ®ion->pages, region->length); +free_region: + kfree(region); + return ret; +} + +static long cxl_cache_ioctl_numa_buffer_unmap(struct dfl_cxl_cache *cxl_cache, void __user *arg) +{ + unsigned long minsz = 0; + long ret = 0; + int i = 0; + struct dfl_cxl_cache_buffer_unmap dma_unmap; + struct dfl_cxl_cache_buffer_region *region; + + minsz = offsetofend(struct dfl_cxl_cache_buffer_unmap, csr_array); + if (copy_from_user(&dma_unmap, arg, minsz)) { + dev_err(cxl_cache->dev, "fails to copy from user space buffer\n"); + return -EFAULT; + } + if (dma_unmap.argsz < minsz) { + dev_err(cxl_cache->dev, "invalid ioctl buffer size\n"); + return -EINVAL; + } + + region = cxl_cache_dma_region_find(cxl_cache, dma_unmap.user_addr, dma_unmap.length); + if (!region) { + dev_err(cxl_cache->dev, "fails to find buffer\n"); + return -EINVAL; + } + + cxl_cache_dma_region_remove(cxl_cache, region); + cxl_cache_unpin_pages(cxl_cache->dev, ®ion->pages, region->length); + + for (i = 0; i < DFL_ARRAY_MAX_SIZE; i++) { + if (dma_unmap.csr_array[i] && dma_unmap.csr_array[i] < cxl_cache->rinfo.size) + writeq(0, cxl_cache->mmio_base + dma_unmap.csr_array[i]); + } + + kfree(region); + return ret; +} + +static long dfl_cxl_cache_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) +{ + struct dfl_cxl_cache *cxl_cache = filp->private_data; + + switch (cmd) { + case DFL_FPGA_GET_API_VERSION: + return DFL_FPGA_GET_API_VERSION; + case DFL_FPGA_CHECK_EXTENSION: + return cxl_cache_ioctl_check_extension(cxl_cache, arg); + case DFL_CXL_CACHE_GET_REGION_INFO: + return cxl_cache_ioctl_get_region_info(cxl_cache, (void __user *)arg); + case DFL_CXL_CACHE_NUMA_BUFFER_MAP: + return cxl_cache_ioctl_numa_buffer_map(cxl_cache, (void __user *)arg); + case DFL_CXL_CACHE_NUMA_BUFFER_UNMAP: + return cxl_cache_ioctl_numa_buffer_unmap(cxl_cache, (void __user *)arg); + default: + return -EINVAL; + } +} + +static const struct vm_operations_struct cxl_cache_vma_ops = { +#ifdef CONFIG_HAVE_IOREMAP_PROT + .access = generic_access_phys, +#endif +}; + +static int dfl_cxl_cache_mmap(struct file *filp, struct vm_area_struct *vma) +{ + struct dfl_cxl_cache *cxl_cache = filp->private_data; + u64 size = vma->vm_end - vma->vm_start; + u64 offset; + + if (!(vma->vm_flags & VM_SHARED)) + return -EINVAL; + + if (!(cxl_cache->rinfo.flags & DFL_CXL_CACHE_REGION_MMAP)) + return -EINVAL; + + if ((vma->vm_flags & VM_READ) && !(cxl_cache->rinfo.flags & DFL_CXL_CACHE_REGION_READ)) + return -EPERM; + + if ((vma->vm_flags & VM_WRITE) && !(cxl_cache->rinfo.flags & DFL_CXL_CACHE_REGION_WRITE)) + return -EPERM; + + offset = PFN_PHYS(vma->vm_pgoff); + + /* Support debug access to the mapping */ + vma->vm_ops = &cxl_cache_vma_ops; + + vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); + + return remap_pfn_range(vma, vma->vm_start, + PFN_DOWN(cxl_cache->ddev->mmio_res.start + + (offset - cxl_cache->rinfo.offset)), + size, vma->vm_page_prot); +} + +static void cxl_cache_dma_region_destroy(struct dfl_cxl_cache *cxl_cache) +{ + struct rb_node *node = rb_first(&cxl_cache->dma_regions); + struct dfl_cxl_cache_buffer_region *region; + + while (node) { + region = container_of(node, struct dfl_cxl_cache_buffer_region, node); + + rb_erase(node, &cxl_cache->dma_regions); + + if (region->pages) + cxl_cache_unpin_pages(cxl_cache->dev, ®ion->pages, region->length); + + node = rb_next(node); + kfree(region); + } +} + +static int dfl_cxl_cache_release(struct inode *inode, struct file *filp) +{ + struct dfl_cxl_cache *cxl_cache = filp->private_data; + + cxl_cache_dma_region_destroy(cxl_cache); + atomic_set(&cxl_cache->opened, 0); + return 0; +} + +static const struct file_operations dfl_cxl_cache_fops = { + .owner = THIS_MODULE, + .open = dfl_cxl_cache_open, + .release = dfl_cxl_cache_release, + .unlocked_ioctl = dfl_cxl_cache_ioctl, + .mmap = dfl_cxl_cache_mmap, +}; + +static void cxl_cache_dev_release(struct device *dev) +{ + struct dfl_cxl_cache *cxl_cache = dev_get_drvdata(dev); + + cdev_del(&cxl_cache->cdev); +} + +static void cxl_cache_chardev_uinit(struct dfl_cxl_cache *cxl_cache) +{ + device_destroy(dfl_cxl_cache_class, + MKDEV(MAJOR(dfl_cxl_cache_devt), cxl_cache->id)); +} + +static int cxl_cache_chardev_init(struct dfl_cxl_cache *cxl_cache, + struct dfl_device *ddev, + void __iomem *mmio_base) +{ + int ret; + + dev_set_drvdata(&ddev->dev, cxl_cache); + cxl_cache->ddev = ddev; + cxl_cache->mmio_base = mmio_base; + cxl_cache->id = dfl_cxl_cache_devices++; + cxl_cache->dma_regions = RB_ROOT; + + cxl_cache->rinfo.argsz = sizeof(struct dfl_cxl_cache_region_info); + cxl_cache->rinfo.flags = DFL_CXL_CACHE_REGION_READ | DFL_CXL_CACHE_REGION_WRITE | + DFL_CXL_CACHE_REGION_MMAP; + cxl_cache->rinfo.size = resource_size(&ddev->mmio_res); + cxl_cache->rinfo.offset = 0; + + cxl_cache->dev = device_create(dfl_cxl_cache_class, &ddev->dev, + MKDEV(MAJOR(dfl_cxl_cache_devt), cxl_cache->id), + cxl_cache, DFL_CXL_CACHE_DRIVER_NAME ".%d", + cxl_cache->id); + + if (IS_ERR(cxl_cache->dev)) { + ret = PTR_ERR(cxl_cache->dev); + dev_err(&ddev->dev, "device_create failed: %d\n", ret); + cxl_cache->dev = NULL; + return ret; + } + cxl_cache->dev->release = cxl_cache_dev_release; + + cdev_init(&cxl_cache->cdev, &dfl_cxl_cache_fops); + cxl_cache->cdev.owner = THIS_MODULE; + cxl_cache->cdev.ops = &dfl_cxl_cache_fops; + + ret = cdev_add(&cxl_cache->cdev, cxl_cache->dev->devt, 1); + if (ret) + dev_err(cxl_cache->dev, "cdev_add failed: %d\n", ret); + + return ret; +} + +static int dfl_cxl_cache_probe(struct dfl_device *ddev) +{ + int ret = 0; + void __iomem *mmio_base; + struct dfl_cxl_cache *cxl_cache; + + guard(mutex)(&dfl_cxl_cache_class_lock); + + if (!dfl_cxl_cache_class) { + dfl_cxl_cache_class = class_create(DFL_CXL_CACHE_DRIVER_NAME); + if (IS_ERR(dfl_cxl_cache_class)) { + ret = PTR_ERR(dfl_cxl_cache_class); + dfl_cxl_cache_class = NULL; + dev_err_probe(&ddev->dev, ret, "class_create failed\n"); + return ret;return dev_err_probe(&ddev->dev, ret, "class_create failed\n");
Yes, that is better.
+ } + } + + if (!MAJOR(dfl_cxl_cache_devt)) { + ret = alloc_chrdev_region(&dfl_cxl_cache_devt, 0, + MINORMASK, + DFL_CXL_CACHE_DRIVER_NAME);Is there a case where alloc_chrdev_region() needs to be undone (unregister_chrdev_region()) before returning from the probe function because of an error below?
Yes, alloc_chrdev_region() needs to be undone if it was called during this first execution of dfl_cxl_cache_probe().
+ if (ret) { + dev_err_probe(&ddev->dev, ret, "alloc_chrdev_region failed\n"); + dfl_cxl_cache_devt = MKDEV(0, 0); + return ret;return dev_err_probe(&ddev->dev, ret, "alloc_chrdev_region failed\n");
Got it.
+ } + } + + mmio_base = devm_ioremap_resource(&ddev->dev, &ddev->mmio_res); + if (IS_ERR(mmio_base)) + return PTR_ERR(mmio_base); + + cxl_cache = devm_kzalloc(&ddev->dev, sizeof(*cxl_cache), GFP_KERNEL); + if (!cxl_cache) + return -ENOMEM; + + ret = cxl_cache_chardev_init(cxl_cache, ddev, mmio_base); + if (ret) + dev_err_probe(&ddev->dev, ret, "cxl_cache_chardev_init failed\n"); + + return ret; +} + +static void dfl_cxl_cache_remove(struct dfl_device *ddev) +{ + struct dfl_cxl_cache *cxl_cache = dev_get_drvdata(&ddev->dev); + + guard(mutex)(&dfl_cxl_cache_class_lock); + cxl_cache_chardev_uinit(cxl_cache); + + if (dfl_cxl_cache_devices-- == 0) {Does dfl_cxl_cache_devices need to be decremented _before_ it is evaluated?
Yes, code above is wrong. Since dfl_cxl_cache_devices is incremented in cxl_cache_chardev_init(), it should be decremented in cxl_cache_chardev_uinit().
if (--dfl_cxl_cache_devices == 0) {+ if (dfl_cxl_cache_class) { + class_destroy(dfl_cxl_cache_class); + dfl_cxl_cache_class = NULL; + } + + if (MAJOR(dfl_cxl_cache_devt)) { + unregister_chrdev_region(dfl_cxl_cache_devt, MINORMASK); + dfl_cxl_cache_devt = MKDEV(0, 0); + } + } +} + +static const struct dfl_device_id dfl_cxl_cache_ids[] = { + { FME_ID, FME_FEATURE_ID_CXL_CACHE }, + { } +}; +MODULE_DEVICE_TABLE(dfl, dfl_cxl_cache_ids); + +static struct dfl_driver dfl_cxl_cache_driver = { + .drv = { + .name = DFL_CXL_CACHE_DRIVER_NAME, + }, + .id_table = dfl_cxl_cache_ids, + .probe = dfl_cxl_cache_probe, + .remove = dfl_cxl_cache_remove, +}; +module_dfl_driver(dfl_cxl_cache_driver); + +MODULE_DESCRIPTION("DFL CXL Cache driver"); +MODULE_AUTHOR("Intel Corporation"); +MODULE_LICENSE("GPL"); diff --git a/include/uapi/linux/fpga-dfl.h b/include/uapi/linux/fpga-dfl.h index 1621b077bf21..866f50b99eb6 100644 --- a/include/uapi/linux/fpga-dfl.h +++ b/include/uapi/linux/fpga-dfl.h @@ -31,6 +31,7 @@ #define DFL_FPGA_BASE 0 #define DFL_PORT_BASE 0x40 #define DFL_FME_BASE 0x80 +#define DFL_CXL_CACHE_BASE 0xA0 /* Common IOCTLs for both FME and AFU file descriptor */ @@ -276,4 +277,101 @@ struct dfl_fpga_fme_port_pr { DFL_FME_BASE + 4, \ struct dfl_fpga_irq_set) + /** + * DFL_CXL_CACHE_GET_REGION_INFO - _IOWR(DFL_FPGA_MAGIC, DFL_CXL_CACHE_BASE + 0, + * struct dfl_cxl_cache_region_info) + * + * Retrieve information about a device memory region. + * Caller provides struct dfl_cxl_cache_region_info with flags. + * Driver returns the region info in other fields. + * Return: 0 on success, -errno on failure. + */ + +#define DFL_CXL_CACHE_GET_REGION_INFO _IO(DFL_FPGA_MAGIC, DFL_CXL_CACHE_BASE + 0) + + /** + * struct dfl_cxl_cache_region_info - CXL cache region information + * @argsz: structure length + * @flags: access permission + * @size: region size (bytes) + * @offset: region offset from start of device fd + * + * to retrieve information about a device memory region + */ +struct dfl_cxl_cache_region_info { + __u32 argsz; + __u32 flags; +#define DFL_CXL_CACHE_REGION_READ _BITUL(0) +#define DFL_CXL_CACHE_REGION_WRITE _BITUL(1) +#define DFL_CXL_CACHE_REGION_MMAP _BITUL(2) + __u64 size; + __u64 offset; +}; + +/** + * DFL_CXL_CACHE_NUMA_BUFFER_MAP - _IOWR(DFL_FPGA_MAGIC, DFL_CXL_CACHE_BASE + 1, + * struct dfl_cxl_cache_buffer_map) + * + * Map the user memory per user_addr, length and numa node which are + * provided by caller. The driver allocates memory on the numa node, + * converts the user's virtual addressto a continuous physical address, + * and writes the physical address to the cxl cache read/write address table CSR. + * + * This interface only accepts page-size aligned user memory for mapping. + * Return: 0 on success, -errno on failure. + */ + +#define DFL_ARRAY_MAX_SIZE 0x10 + +#define DFL_CXL_CACHE_NUMA_BUFFER_MAP _IO(DFL_FPGA_MAGIC, DFL_CXL_CACHE_BASE + 1) + +/** + * struct dfl_cxl_cache_buffer_map - maps user address to physical address. + * @argsz: structure length + * @flags: flags + * @user_addr: user mmap virtual address + * @length: length of mapping (bytes) + * @csr_array: array of region address offset + * + * maps user allocated virtual address to physical address. + */ +struct dfl_cxl_cache_buffer_map { + __u32 argsz; +#define DFL_CXL_BUFFER_MAP_WRITABLE 1 + __u32 flags; + __u64 user_addr; + __u64 length; + __u64 csr_array[DFL_ARRAY_MAX_SIZE]; +}; + +/** + * DFL_CXL_CACHE_NUMA_BUFFER_UNMAP - _IOWR(DFL_FPGA_MAGIC, DFL_CXL_CACHE_BASE + 1, + * struct dfl_cxl_cache_buffer_unmap) + * + * Unmaps the user memory per user_addr and length which are provided by caller + * The driver deletes the physical pages of the user address and writes a zero + * to the read/write address table CSR. + * Return: 0 on success, -errno on failure. + */ + +#define DFL_CXL_CACHE_NUMA_BUFFER_UNMAP _IO(DFL_FPGA_MAGIC, DFL_CXL_CACHE_BASE + 2) + +/** + * struct dfl_cxl_cache_buffer_unmap - unmaps user allocated memory. + * @argsz: structure length + * @flags: flags + * @user_addr: user mmap virtual address + * @length: length of mapping (bytes) + * @csr_array: array of region address offset + * + * unmaps user allocated memory. + */ +struct dfl_cxl_cache_buffer_unmap { + __u32 argsz; + __u32 flags; + __u64 user_addr; + __u64 length; + __u64 csr_array[DFL_ARRAY_MAX_SIZE]; +}; + #endif /* _UAPI_LINUX_FPGA_DFL_H */ -- 2.34.1
