If the importer provides an op for supports_interconnects(), the exporter starts the matching (or negotiation) process (during attach) by invoking the supports_interconnects() which would then call this helper to identify the first common interconnect supported by both exporter and importer.
Note that whether an interconnect is supported between an exporter/importer is ultimately determined by the exporter via the match op it is expected to provide. Cc: Jason Gunthorpe <[email protected]> Cc: Christian Koenig <[email protected]> Cc: Sumit Semwal <[email protected]> Cc: Thomas Hellström <[email protected]> Cc: Simona Vetter <[email protected]> Signed-off-by: Vivek Kasireddy <[email protected]> --- drivers/dma-buf/dma-buf.c | 45 +++++++++++++++++++++++++++- include/linux/dma-buf-interconnect.h | 6 ++++ include/linux/dma-buf.h | 9 ++++++ 3 files changed, 59 insertions(+), 1 deletion(-) diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 162642bd53e8..ed48540d1c1d 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -965,8 +965,11 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev, attach->dev = dev; attach->dmabuf = dmabuf; - if (importer_ops) + if (importer_ops) { attach->peer2peer = importer_ops->allow_peer2peer; + if (importer_ops->supports_interconnects) + attach->allow_ic = true; + } attach->importer_ops = importer_ops; attach->importer_priv = importer_priv; @@ -1680,6 +1683,46 @@ void dma_buf_unmap_interconnect(struct dma_buf_attachment *attach, } EXPORT_SYMBOL_NS_GPL(dma_buf_unmap_interconnect, "DMA_BUF"); +bool dma_buf_match_interconnects(struct dma_buf_attachment *attach, + const struct dma_buf_interconnect_match *exp, + unsigned int exp_ics, + const struct dma_buf_interconnect_match *imp, + unsigned int imp_ics) +{ + const struct dma_buf_interconnect *exp_ic, *imp_ic; + const struct dma_buf_interconnect_ops *ic_ops; + struct dma_buf *dmabuf = attach->dmabuf; + unsigned int i, j; + + if (!exp || !imp) + return false; + + if (!attach->allow_ic) + return false; + + ic_ops = dmabuf->ops->interconnect_ops; + if (!ic_ops || !ic_ops->match_interconnect) + return false; + + for (i = 0; i < exp_ics; i++) { + for (j = 0; j < imp_ics; j++) { + exp_ic = exp[i].interconnect; + imp_ic = imp[j].interconnect; + + if (exp_ic->type == imp_ic->type) { + if (ic_ops->match_interconnect(exp_ic, imp_ic)) { + attach->interconnect.type = exp_ic->type; + return true; + } + } + } + } + + attach->allow_ic = false; + return false; +} +EXPORT_SYMBOL_NS_GPL(dma_buf_match_interconnects, "DMA_BUF"); + #ifdef CONFIG_DEBUG_FS static int dma_buf_debug_show(struct seq_file *s, void *unused) { diff --git a/include/linux/dma-buf-interconnect.h b/include/linux/dma-buf-interconnect.h index 17504dea9691..a72f65ed4806 100644 --- a/include/linux/dma-buf-interconnect.h +++ b/include/linux/dma-buf-interconnect.h @@ -20,10 +20,16 @@ struct dma_buf_interconnect { enum dma_buf_interconnect_type type; }; +struct dma_buf_interconnect_match { + const struct dma_buf_interconnect *interconnect; +}; + struct dma_buf_interconnect_ops { int (*map_interconnect)(struct dma_buf_attachment *attach, struct dma_buf_ranges *ranges); void (*unmap_interconnect)(struct dma_buf_attachment *attach, struct dma_buf_ranges *ranges); + bool (*match_interconnect)(const struct dma_buf_interconnect *exp_ic, + const struct dma_buf_interconnect *imp_ic); }; #endif diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index db91c67c00d6..3e6124387f3c 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -479,6 +479,10 @@ struct dma_buf_attach_ops { * point to the new location of the DMA-buf. */ void (*move_notify)(struct dma_buf_attachment *attach); + + bool (*supports_interconnects)(struct dma_buf_attachment *attach, + const struct dma_buf_interconnect_match *, + unsigned int num_ics); }; /** @@ -599,6 +603,11 @@ void dma_buf_unmap_attachment(struct dma_buf_attachment *, struct sg_table *, struct dma_buf_ranges *dma_buf_map_interconnect(struct dma_buf_attachment *); void dma_buf_unmap_interconnect(struct dma_buf_attachment *, struct dma_buf_ranges *); +bool dma_buf_match_interconnects(struct dma_buf_attachment *attach, + const struct dma_buf_interconnect_match *, + unsigned int exp_ics, + const struct dma_buf_interconnect_match *, + unsigned int imp_ics); void dma_buf_move_notify(struct dma_buf *dma_buf); int dma_buf_begin_cpu_access(struct dma_buf *dma_buf, -- 2.50.1
