diff options
Diffstat (limited to 'drivers/staging/hv/ring_buffer.c')
-rw-r--r-- | drivers/staging/hv/ring_buffer.c | 527 |
1 files changed, 0 insertions, 527 deletions
diff --git a/drivers/staging/hv/ring_buffer.c b/drivers/staging/hv/ring_buffer.c deleted file mode 100644 index 70e2e66..0000000 --- a/drivers/staging/hv/ring_buffer.c +++ /dev/null @@ -1,527 +0,0 @@ -/* - * - * Copyright (c) 2009, Microsoft Corporation. - * - * This program is free software; you can redistribute it and/or modify it - * under the terms and conditions of the GNU General Public License, - * version 2, as published by the Free Software Foundation. - * - * This program is distributed in the hope it will be useful, but WITHOUT - * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or - * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for - * more details. - * - * You should have received a copy of the GNU General Public License along with - * this program; if not, write to the Free Software Foundation, Inc., 59 Temple - * Place - Suite 330, Boston, MA 02111-1307 USA. - * - * Authors: - * Haiyang Zhang <haiyangz@microsoft.com> - * Hank Janssen <hjanssen@microsoft.com> - * K. Y. Srinivasan <kys@microsoft.com> - * - */ -#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt - -#include <linux/kernel.h> -#include <linux/mm.h> - -#include "hyperv.h" -#include "hyperv_vmbus.h" - - -/* #defines */ - - -/* Amount of space to write to */ -#define BYTES_AVAIL_TO_WRITE(r, w, z) \ - ((w) >= (r)) ? ((z) - ((w) - (r))) : ((r) - (w)) - - -/* - * - * hv_get_ringbuffer_availbytes() - * - * Get number of bytes available to read and to write to - * for the specified ring buffer - */ -static inline void -hv_get_ringbuffer_availbytes(struct hv_ring_buffer_info *rbi, - u32 *read, u32 *write) -{ - u32 read_loc, write_loc; - - smp_read_barrier_depends(); - - /* Capture the read/write indices before they changed */ - read_loc = rbi->ring_buffer->read_index; - write_loc = rbi->ring_buffer->write_index; - - *write = BYTES_AVAIL_TO_WRITE(read_loc, write_loc, rbi->ring_datasize); - *read = rbi->ring_datasize - *write; -} - -/* - * hv_get_next_write_location() - * - * Get the next write location for the specified ring buffer - * - */ -static inline u32 -hv_get_next_write_location(struct hv_ring_buffer_info *ring_info) -{ - u32 next = ring_info->ring_buffer->write_index; - - return next; -} - -/* - * hv_set_next_write_location() - * - * Set the next write location for the specified ring buffer - * - */ -static inline void -hv_set_next_write_location(struct hv_ring_buffer_info *ring_info, - u32 next_write_location) -{ - ring_info->ring_buffer->write_index = next_write_location; -} - -/* - * hv_get_next_read_location() - * - * Get the next read location for the specified ring buffer - */ -static inline u32 -hv_get_next_read_location(struct hv_ring_buffer_info *ring_info) -{ - u32 next = ring_info->ring_buffer->read_index; - - return next; -} - -/* - * hv_get_next_readlocation_withoffset() - * - * Get the next read location + offset for the specified ring buffer. - * This allows the caller to skip - */ -static inline u32 -hv_get_next_readlocation_withoffset(struct hv_ring_buffer_info *ring_info, - u32 offset) -{ - u32 next = ring_info->ring_buffer->read_index; - - next += offset; - next %= ring_info->ring_datasize; - - return next; -} - -/* - * - * hv_set_next_read_location() - * - * Set the next read location for the specified ring buffer - * - */ -static inline void -hv_set_next_read_location(struct hv_ring_buffer_info *ring_info, - u32 next_read_location) -{ - ring_info->ring_buffer->read_index = next_read_location; -} - - -/* - * - * hv_get_ring_buffer() - * - * Get the start of the ring buffer - */ -static inline void * -hv_get_ring_buffer(struct hv_ring_buffer_info *ring_info) -{ - return (void *)ring_info->ring_buffer->buffer; -} - - -/* - * - * hv_get_ring_buffersize() - * - * Get the size of the ring buffer - */ -static inline u32 -hv_get_ring_buffersize(struct hv_ring_buffer_info *ring_info) -{ - return ring_info->ring_datasize; -} - -/* - * - * hv_get_ring_bufferindices() - * - * Get the read and write indices as u64 of the specified ring buffer - * - */ -static inline u64 -hv_get_ring_bufferindices(struct hv_ring_buffer_info *ring_info) -{ - return (u64)ring_info->ring_buffer->write_index << 32; -} - - -/* - * - * hv_dump_ring_info() - * - * Dump out to console the ring buffer info - * - */ -void hv_dump_ring_info(struct hv_ring_buffer_info *ring_info, char *prefix) -{ - u32 bytes_avail_towrite; - u32 bytes_avail_toread; - - hv_get_ringbuffer_availbytes(ring_info, - &bytes_avail_toread, - &bytes_avail_towrite); - - DPRINT(VMBUS, - DEBUG_RING_LVL, - "%s <<ringinfo %p buffer %p avail write %u " - "avail read %u read idx %u write idx %u>>", - prefix, - ring_info, - ring_info->ring_buffer->buffer, - bytes_avail_towrite, - bytes_avail_toread, - ring_info->ring_buffer->read_index, - ring_info->ring_buffer->write_index); -} - - -/* - * - * hv_copyfrom_ringbuffer() - * - * Helper routine to copy to source from ring buffer. - * Assume there is enough room. Handles wrap-around in src case only!! - * - */ -static u32 hv_copyfrom_ringbuffer( - struct hv_ring_buffer_info *ring_info, - void *dest, - u32 destlen, - u32 start_read_offset) -{ - void *ring_buffer = hv_get_ring_buffer(ring_info); - u32 ring_buffer_size = hv_get_ring_buffersize(ring_info); - - u32 frag_len; - - /* wrap-around detected at the src */ - if (destlen > ring_buffer_size - start_read_offset) { - frag_len = ring_buffer_size - start_read_offset; - - memcpy(dest, ring_buffer + start_read_offset, frag_len); - memcpy(dest + frag_len, ring_buffer, destlen - frag_len); - } else - - memcpy(dest, ring_buffer + start_read_offset, destlen); - - - start_read_offset += destlen; - start_read_offset %= ring_buffer_size; - - return start_read_offset; -} - - -/* - * - * hv_copyto_ringbuffer() - * - * Helper routine to copy from source to ring buffer. - * Assume there is enough room. Handles wrap-around in dest case only!! - * - */ -static u32 hv_copyto_ringbuffer( - struct hv_ring_buffer_info *ring_info, - u32 start_write_offset, - void *src, - u32 srclen) -{ - void *ring_buffer = hv_get_ring_buffer(ring_info); - u32 ring_buffer_size = hv_get_ring_buffersize(ring_info); - u32 frag_len; - - /* wrap-around detected! */ - if (srclen > ring_buffer_size - start_write_offset) { - frag_len = ring_buffer_size - start_write_offset; - memcpy(ring_buffer + start_write_offset, src, frag_len); - memcpy(ring_buffer, src + frag_len, srclen - frag_len); - } else - memcpy(ring_buffer + start_write_offset, src, srclen); - - start_write_offset += srclen; - start_write_offset %= ring_buffer_size; - - return start_write_offset; -} - -/* - * - * hv_ringbuffer_get_debuginfo() - * - * Get various debug metrics for the specified ring buffer - * - */ -void hv_ringbuffer_get_debuginfo(struct hv_ring_buffer_info *ring_info, - struct hv_ring_buffer_debug_info *debug_info) -{ - u32 bytes_avail_towrite; - u32 bytes_avail_toread; - - if (ring_info->ring_buffer) { - hv_get_ringbuffer_availbytes(ring_info, - &bytes_avail_toread, - &bytes_avail_towrite); - - debug_info->bytes_avail_toread = bytes_avail_toread; - debug_info->bytes_avail_towrite = bytes_avail_towrite; - debug_info->current_read_index = - ring_info->ring_buffer->read_index; - debug_info->current_write_index = - ring_info->ring_buffer->write_index; - debug_info->current_interrupt_mask = - ring_info->ring_buffer->interrupt_mask; - } -} - - -/* - * - * hv_get_ringbuffer_interrupt_mask() - * - * Get the interrupt mask for the specified ring buffer - * - */ -u32 hv_get_ringbuffer_interrupt_mask(struct hv_ring_buffer_info *rbi) -{ - return rbi->ring_buffer->interrupt_mask; -} - -/* - * - * hv_ringbuffer_init() - * - *Initialize the ring buffer - * - */ -int hv_ringbuffer_init(struct hv_ring_buffer_info *ring_info, - void *buffer, u32 buflen) -{ - if (sizeof(struct hv_ring_buffer) != PAGE_SIZE) - return -EINVAL; - - memset(ring_info, 0, sizeof(struct hv_ring_buffer_info)); - - ring_info->ring_buffer = (struct hv_ring_buffer *)buffer; - ring_info->ring_buffer->read_index = - ring_info->ring_buffer->write_index = 0; - - ring_info->ring_size = buflen; - ring_info->ring_datasize = buflen - sizeof(struct hv_ring_buffer); - - spin_lock_init(&ring_info->ring_lock); - - return 0; -} - -/* - * - * hv_ringbuffer_cleanup() - * - * Cleanup the ring buffer - * - */ -void hv_ringbuffer_cleanup(struct hv_ring_buffer_info *ring_info) -{ -} - -/* - * - * hv_ringbuffer_write() - * - * Write to the ring buffer - * - */ -int hv_ringbuffer_write(struct hv_ring_buffer_info *outring_info, - struct scatterlist *sglist, u32 sgcount) -{ - int i = 0; - u32 bytes_avail_towrite; - u32 bytes_avail_toread; - u32 totalbytes_towrite = 0; - - struct scatterlist *sg; - u32 next_write_location; - u64 prev_indices = 0; - unsigned long flags; - - for_each_sg(sglist, sg, sgcount, i) - { - totalbytes_towrite += sg->length; - } - - totalbytes_towrite += sizeof(u64); - - spin_lock_irqsave(&outring_info->ring_lock, flags); - - hv_get_ringbuffer_availbytes(outring_info, - &bytes_avail_toread, - &bytes_avail_towrite); - - - /* If there is only room for the packet, assume it is full. */ - /* Otherwise, the next time around, we think the ring buffer */ - /* is empty since the read index == write index */ - if (bytes_avail_towrite <= totalbytes_towrite) { - spin_unlock_irqrestore(&outring_info->ring_lock, flags); - return -EAGAIN; - } - - /* Write to the ring buffer */ - next_write_location = hv_get_next_write_location(outring_info); - - for_each_sg(sglist, sg, sgcount, i) - { - next_write_location = hv_copyto_ringbuffer(outring_info, - next_write_location, - sg_virt(sg), - sg->length); - } - - /* Set previous packet start */ - prev_indices = hv_get_ring_bufferindices(outring_info); - - next_write_location = hv_copyto_ringbuffer(outring_info, - next_write_location, - &prev_indices, - sizeof(u64)); - - /* Make sure we flush all writes before updating the writeIndex */ - smp_wmb(); - - /* Now, update the write location */ - hv_set_next_write_location(outring_info, next_write_location); - - - spin_unlock_irqrestore(&outring_info->ring_lock, flags); - return 0; -} - - -/* - * - * hv_ringbuffer_peek() - * - * Read without advancing the read index - * - */ -int hv_ringbuffer_peek(struct hv_ring_buffer_info *Inring_info, - void *Buffer, u32 buflen) -{ - u32 bytes_avail_towrite; - u32 bytes_avail_toread; - u32 next_read_location = 0; - unsigned long flags; - - spin_lock_irqsave(&Inring_info->ring_lock, flags); - - hv_get_ringbuffer_availbytes(Inring_info, - &bytes_avail_toread, - &bytes_avail_towrite); - - /* Make sure there is something to read */ - if (bytes_avail_toread < buflen) { - - spin_unlock_irqrestore(&Inring_info->ring_lock, flags); - - return -EAGAIN; - } - - /* Convert to byte offset */ - next_read_location = hv_get_next_read_location(Inring_info); - - next_read_location = hv_copyfrom_ringbuffer(Inring_info, - Buffer, - buflen, - next_read_location); - - spin_unlock_irqrestore(&Inring_info->ring_lock, flags); - - return 0; -} - - -/* - * - * hv_ringbuffer_read() - * - * Read and advance the read index - * - */ -int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info, void *buffer, - u32 buflen, u32 offset) -{ - u32 bytes_avail_towrite; - u32 bytes_avail_toread; - u32 next_read_location = 0; - u64 prev_indices = 0; - unsigned long flags; - - if (buflen <= 0) - return -EINVAL; - - spin_lock_irqsave(&inring_info->ring_lock, flags); - - hv_get_ringbuffer_availbytes(inring_info, - &bytes_avail_toread, - &bytes_avail_towrite); - - /* Make sure there is something to read */ - if (bytes_avail_toread < buflen) { - spin_unlock_irqrestore(&inring_info->ring_lock, flags); - - return -EAGAIN; - } - - next_read_location = - hv_get_next_readlocation_withoffset(inring_info, offset); - - next_read_location = hv_copyfrom_ringbuffer(inring_info, - buffer, - buflen, - next_read_location); - - next_read_location = hv_copyfrom_ringbuffer(inring_info, - &prev_indices, - sizeof(u64), - next_read_location); - - /* Make sure all reads are done before we update the read index since */ - /* the writer may start writing to the read area once the read index */ - /*is updated */ - smp_mb(); - - /* Update the read index */ - hv_set_next_read_location(inring_info, next_read_location); - - spin_unlock_irqrestore(&inring_info->ring_lock, flags); - - return 0; -} |