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Introduce NVMe Direct I/O (HLDIO) infrastructure to support peer‑to‑peer DMA in the habanalabs driver. This adds internal helpers and data structures to enable direct transfers between NVMe storage and device memory. The feature is built only when CONFIG_HL_HLDIO is enabled. A debugfs interface is also provided for functional validation. Signed-off-by: Konstantin Sinyuk <konstantin.sinyuk@intel.com> Reviewed-by: Farah Kassabri <farah.kassabri@intel.com> Reviewed-by: Koby Elbaz <koby.elbaz@intel.com> Signed-off-by: Koby Elbaz <koby.elbaz@intel.com>
147 lines
4.5 KiB
C
147 lines
4.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* hldio.h - NVMe Direct I/O (HLDIO) infrastructure for Habana Labs Driver
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*
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* This feature requires specific hardware setup and must not be built
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* under COMPILE_TEST.
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*/
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#ifndef __HL_HLDIO_H__
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#define __HL_HLDIO_H__
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#include <linux/types.h>
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#include <linux/fs.h>
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#include <linux/seq_file.h>
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#include <linux/ktime.h> /* ktime functions */
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#include <linux/delay.h> /* usleep_range */
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#include <linux/kernel.h> /* might_sleep_if */
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#include <linux/errno.h> /* error codes */
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/* Forward declarations */
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struct hl_device;
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struct file;
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/* Enable only if Kconfig selected */
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#ifdef CONFIG_HL_HLDIO
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/**
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* struct hl_p2p_region - describes a single P2P memory region
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* @p2ppages: array of page structs for the P2P memory
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* @p2pmem: virtual address of the P2P memory region
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* @device_pa: physical address on the device
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* @bar_offset: offset within the BAR
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* @size: size of the region in bytes
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* @bar: BAR number containing this region
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*/
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struct hl_p2p_region {
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struct page **p2ppages;
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void *p2pmem;
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u64 device_pa;
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u64 bar_offset;
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u64 size;
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int bar;
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};
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/**
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* struct hl_dio_stats - Direct I/O statistics
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* @total_ops: total number of operations attempted
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* @successful_ops: number of successful operations
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* @failed_ops: number of failed operations
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* @bytes_transferred: total bytes successfully transferred
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* @last_len_read: length of the last read operation
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*/
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struct hl_dio_stats {
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u64 total_ops;
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u64 successful_ops;
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u64 failed_ops;
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u64 bytes_transferred;
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size_t last_len_read;
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};
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/**
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* struct hl_dio - describes habanalabs direct storage interaction interface
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* @p2prs: array of p2p regions
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* @inflight_ios: percpu counter for inflight ios
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* @np2prs: number of elements in p2prs
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* @io_enabled: 1 if io is enabled 0 otherwise
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*/
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struct hl_dio {
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struct hl_p2p_region *p2prs;
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s64 __percpu *inflight_ios;
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u8 np2prs;
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u8 io_enabled;
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};
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int hl_dio_ssd2hl(struct hl_device *hdev, struct hl_ctx *ctx, int fd,
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u64 device_va, off_t off_bytes, size_t len_bytes,
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size_t *len_read);
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void hl_p2p_region_fini_all(struct hl_device *hdev);
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int hl_p2p_region_init(struct hl_device *hdev, struct hl_p2p_region *p2pr);
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int hl_dio_start(struct hl_device *hdev);
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void hl_dio_stop(struct hl_device *hdev);
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/* Init/teardown */
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int hl_hldio_init(struct hl_device *hdev);
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void hl_hldio_fini(struct hl_device *hdev);
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/* File operations */
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long hl_hldio_ioctl(struct file *filep, unsigned int cmd, unsigned long arg);
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/* DebugFS hooks */
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#ifdef CONFIG_DEBUG_FS
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void hl_hldio_debugfs_init(struct hl_device *hdev);
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void hl_hldio_debugfs_fini(struct hl_device *hdev);
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#else
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static inline void hl_hldio_debugfs_init(struct hl_device *hdev) { }
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static inline void hl_hldio_debugfs_fini(struct hl_device *hdev) { }
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#endif
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#else /* !CONFIG_HL_HLDIO */
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struct hl_p2p_region;
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/* Stubs when HLDIO is disabled */
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static inline int hl_dio_ssd2hl(struct hl_device *hdev, struct hl_ctx *ctx, int fd,
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u64 device_va, off_t off_bytes, size_t len_bytes,
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size_t *len_read)
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{ return -EOPNOTSUPP; }
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static inline void hl_p2p_region_fini_all(struct hl_device *hdev) {}
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static inline int hl_p2p_region_init(struct hl_device *hdev, struct hl_p2p_region *p2pr)
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{ return -EOPNOTSUPP; }
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static inline int hl_dio_start(struct hl_device *hdev) { return -EOPNOTSUPP; }
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static inline void hl_dio_stop(struct hl_device *hdev) {}
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static inline int hl_hldio_init(struct hl_device *hdev) { return 0; }
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static inline void hl_hldio_fini(struct hl_device *hdev) { }
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static inline long hl_hldio_ioctl(struct file *f, unsigned int c,
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unsigned long a)
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{ return -ENOTTY; }
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static inline void hl_hldio_debugfs_init(struct hl_device *hdev) { }
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static inline void hl_hldio_debugfs_fini(struct hl_device *hdev) { }
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#endif /* CONFIG_HL_HLDIO */
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/* Simplified polling macro for HLDIO (no simulator support) */
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#define hl_poll_timeout_condition(hdev, cond, sleep_us, timeout_us) \
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({ \
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ktime_t __timeout = ktime_add_us(ktime_get(), timeout_us); \
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might_sleep_if(sleep_us); \
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(void)(hdev); /* keep signature consistent, hdev unused */ \
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for (;;) { \
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mb(); /* ensure ordering of memory operations */ \
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if (cond) \
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break; \
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if (timeout_us && ktime_compare(ktime_get(), __timeout) > 0) \
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break; \
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if (sleep_us) \
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usleep_range((sleep_us >> 2) + 1, sleep_us); \
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} \
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(cond) ? 0 : -ETIMEDOUT; \
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})
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#ifdef CONFIG_HL_HLDIO
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bool hl_device_supports_nvme(struct hl_device *hdev);
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#else
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static inline bool hl_device_supports_nvme(struct hl_device *hdev) { return false; }
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#endif
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#endif /* __HL_HLDIO_H__ */
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