+static int
+nfp_nsp_command_buf_dma_sg(struct nfp_nsp *nsp,
+ struct nfp_nsp_command_buf_arg *arg,
+ unsigned int max_size, unsigned int chunk_order,
+ unsigned int dma_order)
+{
+ struct nfp_cpp *cpp = nsp->cpp;
+ struct nfp_nsp_dma_buf *desc;
+ struct {
+ dma_addr_t dma_addr;
+ unsigned long len;
+ void *chunk;
+ } *chunks;
+ size_t chunk_size, dma_size;
+ dma_addr_t dma_desc;
+ struct device *dev;
+ unsigned long off;
+ int i, ret, nseg;
+ size_t desc_sz;
+
+ chunk_size = BIT_ULL(chunk_order);
+ dma_size = BIT_ULL(dma_order);
+ nseg = DIV_ROUND_UP(max_size, chunk_size);
+
+ chunks = kzalloc(array_size(sizeof(*chunks), nseg), GFP_KERNEL);
+ if (!chunks)
+ return -ENOMEM;
+
+ off = 0;
+ ret = -ENOMEM;
+ for (i = 0; i < nseg; i++) {
+ unsigned long coff;
+
+ chunks[i].chunk = kmalloc(chunk_size,
+ GFP_KERNEL | __GFP_NOWARN);
+ if (!chunks[i].chunk)
+ goto exit_free_prev;
+
+ chunks[i].len = min_t(u64, chunk_size, max_size - off);
+
+ coff = 0;
+ if (arg->in_size > off) {
+ coff = min_t(u64, arg->in_size - off, chunk_size);
+ memcpy(chunks[i].chunk, arg->in_buf + off, coff);
+ }
+ memset(chunks[i].chunk + coff, 0, chunk_size - coff);
+
+ off += chunks[i].len;
+ }
+
+ dev = nfp_cpp_device(cpp)->parent;
+
+ for (i = 0; i < nseg; i++) {
+ dma_addr_t addr;
+
+ addr = dma_map_single(dev, chunks[i].chunk, chunks[i].len,
+ DMA_BIDIRECTIONAL);
+ chunks[i].dma_addr = addr;
+
+ ret = dma_mapping_error(dev, addr);
+ if (ret)
+ goto exit_unmap_prev;
+
+ if (WARN_ONCE(round_down(addr, dma_size) !=
+ round_down(addr + chunks[i].len - 1, dma_size),
+ "unaligned DMA address: %pad %lu %zd\n",
+ &addr, chunks[i].len, dma_size)) {
+ ret = -EFAULT;
+ i++;
+ goto exit_unmap_prev;
+ }
+ }
+
+ desc_sz = struct_size(desc, descs, nseg);
+ desc = kmalloc(desc_sz, GFP_KERNEL);
+ if (!desc) {
+ ret = -ENOMEM;
+ goto exit_unmap_all;
+ }
+
+ desc->chunk_cnt = cpu_to_le32(nseg);
+ for (i = 0; i < nseg; i++) {
+ desc->descs[i].size = cpu_to_le32(chunks[i].len);
+ desc->descs[i].addr = cpu_to_le64(chunks[i].dma_addr);
+ }
+
+ dma_desc = dma_map_single(dev, desc, desc_sz, DMA_TO_DEVICE);
+ ret = dma_mapping_error(dev, dma_desc);
+ if (ret)
+ goto exit_free_desc;
+
+ arg->arg.dma = true;
+ arg->arg.buf = dma_desc;
+ ret = __nfp_nsp_command(nsp, &arg->arg);
+ if (ret < 0)
+ goto exit_unmap_desc;
+
+ i = 0;
+ off = 0;
+ while (off < arg->out_size) {
+ unsigned int len;
+
+ len = min_t(u64, chunks[i].len, arg->out_size - off);
+ memcpy(arg->out_buf + off, chunks[i].chunk, len);
+ off += len;
+ i++;
+ }
+
+exit_unmap_desc:
+ dma_unmap_single(dev, dma_desc, desc_sz, DMA_TO_DEVICE);
+exit_free_desc:
+ kfree(desc);
+exit_unmap_all:
+ i = nseg;
+exit_unmap_prev:
+ while (--i >= 0)
+ dma_unmap_single(dev, chunks[i].dma_addr, chunks[i].len,
+ DMA_BIDIRECTIONAL);
+ i = nseg;
+exit_free_prev:
+ while (--i >= 0)
+ kfree(chunks[i].chunk);
+ kfree(chunks);
+ if (ret < 0)
+ nfp_err(cpp, "NSP: SG DMA failed for command 0x%04x: %d (sz:%d cord:%d)\n",
+ arg->arg.code, ret, max_size, chunk_order);
+ return ret;
+}
+
+static int
+nfp_nsp_command_buf_dma(struct nfp_nsp *nsp,
+ struct nfp_nsp_command_buf_arg *arg,
+ unsigned int max_size, unsigned int dma_order)
+{
+ unsigned int chunk_order, buf_order;
+ struct nfp_cpp *cpp = nsp->cpp;
+ bool sg_ok;
+ u64 reg;
+ int err;
+
+ buf_order = order_base_2(roundup_pow_of_two(max_size));
+
+ err = nfp_cpp_readq(cpp, nfp_resource_cpp_id(nsp->res),
+ nfp_resource_address(nsp->res) + NFP_CAP_CMD_DMA_SG,
+ ®);
+ if (err < 0)
+ return err;
+ sg_ok = reg & BIT_ULL(arg->arg.code - 1);
+
+ if (!sg_ok) {
+ if (buf_order > dma_order) {
+ nfp_err(cpp, "NSP: can't service non-SG DMA for command 0x%04x\n",
+ arg->arg.code);
+ return -ENOMEM;
+ }
+ chunk_order = buf_order;
+ } else {
+ chunk_order = min_t(unsigned int, dma_order, PAGE_SHIFT);
+ }
+
+ return nfp_nsp_command_buf_dma_sg(nsp, arg, max_size, chunk_order,
+ dma_order);
+}
+