dma/idxd/dma.c

// SPDX-License-Identifier: GPL-2.0
/* Copyright(c) 2019 Intel Corporation. All rights rsvd. */
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/device.h>
#include <linux/io-64-nonatomic-lo-hi.h>
#include <linux/dmaengine.h>
#include <uapi/linux/idxd.h>
#include "../dmaengine.h"
#include "registers.h"
#include "idxd.h"

static inline struct idxd_wq *to_idxd_wq(struct dma_chan *c)
{
	struct idxd_dma_chan *idxd_chan;

	idxd_chan = container_of(c, struct idxd_dma_chan, chan);
	return idxd_chan->wq;
}

void idxd_dma_complete_txd(struct idxd_desc *desc,
			   enum idxd_complete_type comp_type)
{
	struct dma_async_tx_descriptor *tx;
	struct dmaengine_result res;
	int complete = 1;

	if (desc->completion->status == DSA_COMP_SUCCESS)
		res.result = DMA_TRANS_NOERROR;
	else if (desc->completion->status)
		res.result = DMA_TRANS_WRITE_FAILED;
	else if (comp_type == IDXD_COMPLETE_ABORT)
		res.result = DMA_TRANS_ABORTED;
	else
		complete = 0;

	tx = &desc->txd;
	if (complete && tx->cookie) {
		dma_cookie_complete(tx);
		dma_descriptor_unmap(tx);
		dmaengine_desc_get_callback_invoke(tx, &res);
		tx->callback = NULL;
		tx->callback_result = NULL;
	}
}

static void op_flag_setup(unsigned long flags, u32 *desc_flags)
{
	*desc_flags = IDXD_OP_FLAG_CRAV | IDXD_OP_FLAG_RCR;
	if (flags & DMA_PREP_INTERRUPT)
		*desc_flags |= IDXD_OP_FLAG_RCI;
}

static inline void set_completion_address(struct idxd_desc *desc,
					  u64 *compl_addr)
{
		*compl_addr = desc->compl_dma;
}

static inline void idxd_prep_desc_common(struct idxd_wq *wq,
					 struct dsa_hw_desc *hw, char opcode,
					 u64 addr_f1, u64 addr_f2, u64 len,
					 u64 compl, u32 flags)
{
	struct idxd_device *idxd = wq->idxd;

	hw->flags = flags;
	hw->opcode = opcode;
	hw->src_addr = addr_f1;
	hw->dst_addr = addr_f2;
	hw->xfer_size = len;
	hw->priv = !!(wq->type == IDXD_WQT_KERNEL);
	hw->completion_addr = compl;

	/*
	 * Descriptor completion vectors are 1-8 for MSIX. We will round
	 * robin through the 8 vectors.
	 */
	wq->vec_ptr = (wq->vec_ptr % idxd->num_wq_irqs) + 1;
	hw->int_handle =  wq->vec_ptr;
}

static struct dma_async_tx_descriptor *
idxd_dma_submit_memcpy(struct dma_chan *c, dma_addr_t dma_dest,
		       dma_addr_t dma_src, size_t len, unsigned long flags)
{
	struct idxd_wq *wq = to_idxd_wq(c);
	u32 desc_flags;
	struct idxd_device *idxd = wq->idxd;
	struct idxd_desc *desc;

	if (wq->state != IDXD_WQ_ENABLED)
		return NULL;

	if (len > idxd->max_xfer_bytes)
		return NULL;

	op_flag_setup(flags, &desc_flags);
	desc = idxd_alloc_desc(wq, IDXD_OP_BLOCK);
	if (IS_ERR(desc))
		return NULL;

	idxd_prep_desc_common(wq, desc->hw, DSA_OPCODE_MEMMOVE,
			      dma_src, dma_dest, len, desc->compl_dma,
			      desc_flags);

	desc->txd.flags = flags;

	return &desc->txd;
}

static int idxd_dma_alloc_chan_resources(struct dma_chan *chan)
{
	struct idxd_wq *wq = to_idxd_wq(chan);
	struct device *dev = &wq->idxd->pdev->dev;

	idxd_wq_get(wq);
	dev_dbg(dev, "%s: client_count: %d\n", __func__,
		idxd_wq_refcount(wq));
	return 0;
}

static void idxd_dma_free_chan_resources(struct dma_chan *chan)
{
	struct idxd_wq *wq = to_idxd_wq(chan);
	struct device *dev = &wq->idxd->pdev->dev;

	idxd_wq_put(wq);
	dev_dbg(dev, "%s: client_count: %d\n", __func__,
		idxd_wq_refcount(wq));
}

static enum dma_status idxd_dma_tx_status(struct dma_chan *dma_chan,
					  dma_cookie_t cookie,
					  struct dma_tx_state *txstate)
{
	return DMA_OUT_OF_ORDER;
}

/*
 * issue_pending() does not need to do anything since tx_submit() does the job
 * already.
 */
static void idxd_dma_issue_pending(struct dma_chan *dma_chan)
{
}

static dma_cookie_t idxd_dma_tx_submit(struct dma_async_tx_descriptor *tx)
{
	struct dma_chan *c = tx->chan;
	struct idxd_wq *wq = to_idxd_wq(c);
	dma_cookie_t cookie;
	int rc;
	struct idxd_desc *desc = container_of(tx, struct idxd_desc, txd);

	cookie = dma_cookie_assign(tx);

	rc = idxd_submit_desc(wq, desc);
	if (rc < 0) {
		idxd_free_desc(wq, desc);
		return rc;
	}

	return cookie;
}

static void idxd_dma_release(struct dma_device *device)
{
	struct idxd_dma_dev *idxd_dma = container_of(device, struct idxd_dma_dev, dma);

	kfree(idxd_dma);
}

int idxd_register_dma_device(struct idxd_device *idxd)
{
	struct idxd_dma_dev *idxd_dma;
	struct dma_device *dma;
	struct device *dev = &idxd->pdev->dev;
	int rc;

	idxd_dma = kzalloc_node(sizeof(*idxd_dma), GFP_KERNEL, dev_to_node(dev));
	if (!idxd_dma)
		return -ENOMEM;

	dma = &idxd_dma->dma;
	INIT_LIST_HEAD(&dma->channels);
	dma->dev = dev;

	dma_cap_set(DMA_PRIVATE, dma->cap_mask);
	dma_cap_set(DMA_COMPLETION_NO_ORDER, dma->cap_mask);
	dma->device_release = idxd_dma_release;

	if (idxd->hw.opcap.bits[0] & IDXD_OPCAP_MEMMOVE) {
		dma_cap_set(DMA_MEMCPY, dma->cap_mask);
		dma->device_prep_dma_memcpy = idxd_dma_submit_memcpy;
	}

	dma->device_tx_status = idxd_dma_tx_status;
	dma->device_issue_pending = idxd_dma_issue_pending;
	dma->device_alloc_chan_resources = idxd_dma_alloc_chan_resources;
	dma->device_free_chan_resources = idxd_dma_free_chan_resources;

	rc = dma_async_device_register(dma);
	if (rc < 0) {
		kfree(idxd_dma);
		return rc;
	}

	idxd_dma->idxd = idxd;
	/*
	 * This pointer is protected by the refs taken by the dma_chan. It will remain valid
	 * as long as there are outstanding channels.
	 */
	idxd->idxd_dma = idxd_dma;
	return 0;
}

void idxd_unregister_dma_device(struct idxd_device *idxd)
{
	dma_async_device_unregister(&idxd->idxd_dma->dma);
}

int idxd_register_dma_channel(struct idxd_wq *wq)
{
	struct idxd_device *idxd = wq->idxd;
	struct dma_device *dma = &idxd->idxd_dma->dma;
	struct device *dev = &idxd->pdev->dev;
	struct idxd_dma_chan *idxd_chan;
	struct dma_chan *chan;
	int rc, i;

	idxd_chan = kzalloc_node(sizeof(*idxd_chan), GFP_KERNEL, dev_to_node(dev));
	if (!idxd_chan)
		return -ENOMEM;

	chan = &idxd_chan->chan;
	chan->device = dma;
	list_add_tail(&chan->device_node, &dma->channels);

	for (i = 0; i < wq->num_descs; i++) {
		struct idxd_desc *desc = wq->descs[i];

		dma_async_tx_descriptor_init(&desc->txd, chan);
		desc->txd.tx_submit = idxd_dma_tx_submit;
	}

	rc = dma_async_device_channel_register(dma, chan);
	if (rc < 0) {
		kfree(idxd_chan);
		return rc;
	}

	wq->idxd_chan = idxd_chan;
	idxd_chan->wq = wq;
	get_device(&wq->conf_dev);

	return 0;
}

void idxd_unregister_dma_channel(struct idxd_wq *wq)
{
	struct idxd_dma_chan *idxd_chan = wq->idxd_chan;
	struct dma_chan *chan = &idxd_chan->chan;
	struct idxd_dma_dev *idxd_dma = wq->idxd->idxd_dma;

	dma_async_device_channel_unregister(&idxd_dma->dma, chan);
	list_del(&chan->device_node);
	kfree(wq->idxd_chan);
	wq->idxd_chan = NULL;
	put_device(&wq->conf_dev);
}