From 8171ee35e2ff3cea6c76280e361cf628b3a8c8df Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Wed, 6 Jul 2011 08:02:14 +0200 Subject: dma-helpers: add dma_buf_read and dma_buf_write These helpers do a full transfer from an in-memory buffer to target memory, with support for scatter/gather lists. It will be used to store the reply of an emulated command into a QEMUSGList provided by the adapter. Signed-off-by: Paolo Bonzini --- dma-helpers.c | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) (limited to 'dma-helpers.c') diff --git a/dma-helpers.c b/dma-helpers.c index f08cdb5454..df0a42172f 100644 --- a/dma-helpers.c +++ b/dma-helpers.c @@ -204,3 +204,34 @@ BlockDriverAIOCB *dma_bdrv_write(BlockDriverState *bs, { return dma_bdrv_io(bs, sg, sector, bdrv_aio_writev, cb, opaque, true); } + + +static uint64_t dma_buf_rw(uint8_t *ptr, int32_t len, QEMUSGList *sg, bool to_dev) +{ + uint64_t resid; + int sg_cur_index; + + resid = sg->size; + sg_cur_index = 0; + len = MIN(len, resid); + while (len > 0) { + ScatterGatherEntry entry = sg->sg[sg_cur_index++]; + int32_t xfer = MIN(len, entry.len); + cpu_physical_memory_rw(entry.base, ptr, xfer, !to_dev); + ptr += xfer; + len -= xfer; + resid -= xfer; + } + + return resid; +} + +uint64_t dma_buf_read(uint8_t *ptr, int32_t len, QEMUSGList *sg) +{ + return dma_buf_rw(ptr, len, sg, 0); +} + +uint64_t dma_buf_write(uint8_t *ptr, int32_t len, QEMUSGList *sg) +{ + return dma_buf_rw(ptr, len, sg, 1); +} -- cgit v1.2.1