| /* |
| * |
| * 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; |
| } |