diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/misc/cxl/cxllib.c | 271 |
1 files changed, 271 insertions, 0 deletions
diff --git a/drivers/misc/cxl/cxllib.c b/drivers/misc/cxl/cxllib.c new file mode 100644 index 000000000..e5fe0a171 --- /dev/null +++ b/drivers/misc/cxl/cxllib.c @@ -0,0 +1,271 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright 2017 IBM Corp. + */ + +#include <linux/hugetlb.h> +#include <linux/sched/mm.h> +#include <asm/opal-api.h> +#include <asm/pnv-pci.h> +#include <misc/cxllib.h> + +#include "cxl.h" + +#define CXL_INVALID_DRA ~0ull +#define CXL_DUMMY_READ_SIZE 128 +#define CXL_DUMMY_READ_ALIGN 8 +#define CXL_CAPI_WINDOW_START 0x2000000000000ull +#define CXL_CAPI_WINDOW_LOG_SIZE 48 +#define CXL_XSL_CONFIG_CURRENT_VERSION CXL_XSL_CONFIG_VERSION1 + + +bool cxllib_slot_is_supported(struct pci_dev *dev, unsigned long flags) +{ + int rc; + u32 phb_index; + u64 chip_id, capp_unit_id; + + /* No flags currently supported */ + if (flags) + return false; + + if (!cpu_has_feature(CPU_FTR_HVMODE)) + return false; + + if (!cxl_is_power9()) + return false; + + if (cxl_slot_is_switched(dev)) + return false; + + /* on p9, some pci slots are not connected to a CAPP unit */ + rc = cxl_calc_capp_routing(dev, &chip_id, &phb_index, &capp_unit_id); + if (rc) + return false; + + return true; +} +EXPORT_SYMBOL_GPL(cxllib_slot_is_supported); + +static DEFINE_MUTEX(dra_mutex); +static u64 dummy_read_addr = CXL_INVALID_DRA; + +static int allocate_dummy_read_buf(void) +{ + u64 buf, vaddr; + size_t buf_size; + + /* + * Dummy read buffer is 128-byte long, aligned on a + * 256-byte boundary and we need the physical address. + */ + buf_size = CXL_DUMMY_READ_SIZE + (1ull << CXL_DUMMY_READ_ALIGN); + buf = (u64) kzalloc(buf_size, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + vaddr = (buf + (1ull << CXL_DUMMY_READ_ALIGN) - 1) & + (~0ull << CXL_DUMMY_READ_ALIGN); + + WARN((vaddr + CXL_DUMMY_READ_SIZE) > (buf + buf_size), + "Dummy read buffer alignment issue"); + dummy_read_addr = virt_to_phys((void *) vaddr); + return 0; +} + +int cxllib_get_xsl_config(struct pci_dev *dev, struct cxllib_xsl_config *cfg) +{ + int rc; + u32 phb_index; + u64 chip_id, capp_unit_id; + + if (!cpu_has_feature(CPU_FTR_HVMODE)) + return -EINVAL; + + mutex_lock(&dra_mutex); + if (dummy_read_addr == CXL_INVALID_DRA) { + rc = allocate_dummy_read_buf(); + if (rc) { + mutex_unlock(&dra_mutex); + return rc; + } + } + mutex_unlock(&dra_mutex); + + rc = cxl_calc_capp_routing(dev, &chip_id, &phb_index, &capp_unit_id); + if (rc) + return rc; + + rc = cxl_get_xsl9_dsnctl(dev, capp_unit_id, &cfg->dsnctl); + if (rc) + return rc; + + cfg->version = CXL_XSL_CONFIG_CURRENT_VERSION; + cfg->log_bar_size = CXL_CAPI_WINDOW_LOG_SIZE; + cfg->bar_addr = CXL_CAPI_WINDOW_START; + cfg->dra = dummy_read_addr; + return 0; +} +EXPORT_SYMBOL_GPL(cxllib_get_xsl_config); + +int cxllib_switch_phb_mode(struct pci_dev *dev, enum cxllib_mode mode, + unsigned long flags) +{ + int rc = 0; + + if (!cpu_has_feature(CPU_FTR_HVMODE)) + return -EINVAL; + + switch (mode) { + case CXL_MODE_PCI: + /* + * We currently don't support going back to PCI mode + * However, we'll turn the invalidations off, so that + * the firmware doesn't have to ack them and can do + * things like reset, etc.. with no worries. + * So always return EPERM (can't go back to PCI) or + * EBUSY if we couldn't even turn off snooping + */ + rc = pnv_phb_to_cxl_mode(dev, OPAL_PHB_CAPI_MODE_SNOOP_OFF); + if (rc) + rc = -EBUSY; + else + rc = -EPERM; + break; + case CXL_MODE_CXL: + /* DMA only supported on TVT1 for the time being */ + if (flags != CXL_MODE_DMA_TVT1) + return -EINVAL; + rc = pnv_phb_to_cxl_mode(dev, OPAL_PHB_CAPI_MODE_DMA_TVT1); + if (rc) + return rc; + rc = pnv_phb_to_cxl_mode(dev, OPAL_PHB_CAPI_MODE_SNOOP_ON); + break; + default: + rc = -EINVAL; + } + return rc; +} +EXPORT_SYMBOL_GPL(cxllib_switch_phb_mode); + +/* + * When switching the PHB to capi mode, the TVT#1 entry for + * the Partitionable Endpoint is set in bypass mode, like + * in PCI mode. + * Configure the device dma to use TVT#1, which is done + * by calling dma_set_mask() with a mask large enough. + */ +int cxllib_set_device_dma(struct pci_dev *dev, unsigned long flags) +{ + int rc; + + if (flags) + return -EINVAL; + + rc = dma_set_mask(&dev->dev, DMA_BIT_MASK(64)); + return rc; +} +EXPORT_SYMBOL_GPL(cxllib_set_device_dma); + +int cxllib_get_PE_attributes(struct task_struct *task, + unsigned long translation_mode, + struct cxllib_pe_attributes *attr) +{ + if (translation_mode != CXL_TRANSLATED_MODE && + translation_mode != CXL_REAL_MODE) + return -EINVAL; + + attr->sr = cxl_calculate_sr(false, + task == NULL, + translation_mode == CXL_REAL_MODE, + true); + attr->lpid = mfspr(SPRN_LPID); + if (task) { + struct mm_struct *mm = get_task_mm(task); + if (mm == NULL) + return -EINVAL; + /* + * Caller is keeping a reference on mm_users for as long + * as XSL uses the memory context + */ + attr->pid = mm->context.id; + mmput(mm); + attr->tid = task->thread.tidr; + } else { + attr->pid = 0; + attr->tid = 0; + } + return 0; +} +EXPORT_SYMBOL_GPL(cxllib_get_PE_attributes); + +static int get_vma_info(struct mm_struct *mm, u64 addr, + u64 *vma_start, u64 *vma_end, + unsigned long *page_size) +{ + struct vm_area_struct *vma = NULL; + int rc = 0; + + mmap_read_lock(mm); + + vma = find_vma(mm, addr); + if (!vma) { + rc = -EFAULT; + goto out; + } + *page_size = vma_kernel_pagesize(vma); + *vma_start = vma->vm_start; + *vma_end = vma->vm_end; +out: + mmap_read_unlock(mm); + return rc; +} + +int cxllib_handle_fault(struct mm_struct *mm, u64 addr, u64 size, u64 flags) +{ + int rc; + u64 dar, vma_start, vma_end; + unsigned long page_size; + + if (mm == NULL) + return -EFAULT; + + /* + * The buffer we have to process can extend over several pages + * and may also cover several VMAs. + * We iterate over all the pages. The page size could vary + * between VMAs. + */ + rc = get_vma_info(mm, addr, &vma_start, &vma_end, &page_size); + if (rc) + return rc; + + for (dar = (addr & ~(page_size - 1)); dar < (addr + size); + dar += page_size) { + if (dar < vma_start || dar >= vma_end) { + /* + * We don't hold mm->mmap_lock while iterating, since + * the lock is required by one of the lower-level page + * fault processing functions and it could + * create a deadlock. + * + * It means the VMAs can be altered between 2 + * loop iterations and we could theoretically + * miss a page (however unlikely). But that's + * not really a problem, as the driver will + * retry access, get another page fault on the + * missing page and call us again. + */ + rc = get_vma_info(mm, dar, &vma_start, &vma_end, + &page_size); + if (rc) + return rc; + } + + rc = cxl_handle_mm_fault(mm, flags, dar); + if (rc) + return -EFAULT; + } + return 0; +} +EXPORT_SYMBOL_GPL(cxllib_handle_fault); |