[RFC PATCH v1 02/13] crypto: iaa - Add support for irq-less crypto async interface

[Kanchana P Sridhar <kanchana.p.sridhar@intel.com>]

Add a crypto acomp poll() implementation so that callers can use true
async iaa compress/decompress without interrupts.

To use this mode with zswap, select the 'async' iaa_crypto
driver_sync_mode:

  echo async > /sys/bus/dsa/drivers/crypto/sync_mode

This will cause the iaa_crypto driver to register its acomp_alg
implementation using a non-NULL poll() member, which callers such as
zswap can check for the presence of and use true async mode if found.

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Kanchana P Sridhar <kanchana.p.sridhar@intel.com>
---
 drivers/crypto/intel/iaa/iaa_crypto_main.c | 74 ++++++++++++++++++++++
 1 file changed, 74 insertions(+)

diff --git a/drivers/crypto/intel/iaa/iaa_crypto_main.c b/drivers/crypto/intel/iaa/iaa_crypto_main.c
index 237f87000070..6a8577ac1330 100644
--- a/drivers/crypto/intel/iaa/iaa_crypto_main.c
+++ b/drivers/crypto/intel/iaa/iaa_crypto_main.c
@@ -1788,6 +1788,74 @@ static void compression_ctx_init(struct iaa_compression_ctx *ctx)
 	ctx->use_irq = use_irq;
 }
 
+static int iaa_comp_poll(struct acomp_req *req)
+{
+	struct idxd_desc *idxd_desc;
+	struct idxd_device *idxd;
+	struct iaa_wq *iaa_wq;
+	struct pci_dev *pdev;
+	struct device *dev;
+	struct idxd_wq *wq;
+	bool compress_op;
+	int ret;
+
+	idxd_desc = req->base.data;
+	if (!idxd_desc)
+		return -EAGAIN;
+
+	compress_op = (idxd_desc->iax_hw->opcode == IAX_OPCODE_COMPRESS);
+	wq = idxd_desc->wq;
+	iaa_wq = idxd_wq_get_private(wq);
+	idxd = iaa_wq->iaa_device->idxd;
+	pdev = idxd->pdev;
+	dev = &pdev->dev;
+
+	ret = check_completion(dev, idxd_desc->iax_completion, true, true);
+	if (ret == -EAGAIN)
+		return ret;
+	if (ret)
+		goto out;
+
+	req->dlen = idxd_desc->iax_completion->output_size;
+
+	/* Update stats */
+	if (compress_op) {
+		update_total_comp_bytes_out(req->dlen);
+		update_wq_comp_bytes(wq, req->dlen);
+	} else {
+		update_total_decomp_bytes_in(req->slen);
+		update_wq_decomp_bytes(wq, req->slen);
+	}
+
+	if (iaa_verify_compress && (idxd_desc->iax_hw->opcode == IAX_OPCODE_COMPRESS)) {
+		struct crypto_tfm *tfm = req->base.tfm;
+		dma_addr_t src_addr, dst_addr;
+		u32 compression_crc;
+
+		compression_crc = idxd_desc->iax_completion->crc;
+
+		dma_sync_sg_for_device(dev, req->dst, 1, DMA_FROM_DEVICE);
+		dma_sync_sg_for_device(dev, req->src, 1, DMA_TO_DEVICE);
+
+		src_addr = sg_dma_address(req->src);
+		dst_addr = sg_dma_address(req->dst);
+
+		ret = iaa_compress_verify(tfm, req, wq, src_addr, req->slen,
+					  dst_addr, &req->dlen, compression_crc);
+	}
+out:
+	/* caller doesn't call crypto_wait_req, so no acomp_request_complete() */
+
+	dma_unmap_sg(dev, req->dst, sg_nents(req->dst), DMA_FROM_DEVICE);
+	dma_unmap_sg(dev, req->src, sg_nents(req->src), DMA_TO_DEVICE);
+
+	idxd_free_desc(idxd_desc->wq, idxd_desc);
+
+	dev_dbg(dev, "%s: returning ret=%d\n", __func__, ret);
+
+	return ret;
+}
+
 static int iaa_comp_init_fixed(struct crypto_acomp *acomp_tfm)
 {
 	struct crypto_tfm *tfm = crypto_acomp_tfm(acomp_tfm);
@@ -1813,6 +1881,7 @@ static struct acomp_alg iaa_acomp_fixed_deflate = {
 	.compress		= iaa_comp_acompress,
 	.decompress		= iaa_comp_adecompress,
 	.dst_free               = dst_free,
+	.poll			= iaa_comp_poll,
 	.base			= {
 		.cra_name		= "deflate",
 		.cra_driver_name	= "deflate-iaa",
@@ -1827,6 +1896,11 @@ static int iaa_register_compression_device(void)
 {
 	int ret;
 
+	if (async_mode && !use_irq)
+		iaa_acomp_fixed_deflate.poll = iaa_comp_poll;
+	else
+		iaa_acomp_fixed_deflate.poll = NULL;
+
 	ret = crypto_register_acomp(&iaa_acomp_fixed_deflate);
 	if (ret) {
 		pr_err("deflate algorithm acomp fixed registration failed (%d)\n", ret);
-- 
2.27.0