[RFC,v3,1/7] dmaengine: Add Synopsys eDMA IP core driver

Jose Abreu
2019-01-16T10:21:35Z

Hi Gustavo,

On 1/11/2019 6:33 PM, Gustavo Pimentel wrote:
> Add Synopsys eDMA IP core driver to kernel.
>
> This core driver, initializes and configures the eDMA IP using vma-helpers
> functions and dma-engine subsystem.
>
> Also creates an abstration layer through callbacks allowing different
> registers mappings in the future, organized in to versions.
>
> This driver can be compile as built-in or external module in kernel.
>
> To enable this driver just select DW_EDMA option in kernel configuration,
> however it requires and selects automatically DMA_ENGINE and
> DMA_VIRTUAL_CHANNELS option too.
>
> Changes:
> RFC v1->RFC v2:
> - Replace comments // (C99 style) by /**/
> - Fix the headers of the .c and .h files according to the most recent
> convention
> - Fix errors and checks pointed out by checkpatch with --strict option
> - Replace patch small description tag from dma by dmaengine
> - Change some dev_info() into dev_dbg()
> - Remove unnecessary zero initialization after kzalloc
> - Remove direction validation on config() API, since the direction
> parameter is deprecated
> - Refactor code to replace atomic_t by u32 variable type
> - Replace start_transfer() name by dw_edma_start_transfer()
> - Add spinlock to dw_edma_device_prep_slave_sg()
> - Add spinlock to dw_edma_free_chunk()
> - Simplify switch case into if on dw_edma_device_pause(),
> dw_edma_device_resume() and dw_edma_device_terminate_all()
> RFC v2->RFC v3:
> - Add driver parameter to disable msix feature
> - Fix printk variable of phys_addr_t type
> - Fix printk variable of __iomem type
> - Fix printk variable of size_t type
> - Add comments or improve existing ones
> - Add possibility to work with multiple IRQs feature
> - Fix source and destination addresses
> - Add define to magic numbers
> - Add DMA cyclic transfer feature
>
> Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
> Cc: Vinod Koul <vkoul@kernel.org>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Eugeniy Paltsev <paltsev@synopsys.com>
> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Cc: Russell King <rmk+kernel@armlinux.org.uk>
> Cc: Niklas Cassel <niklas.cassel@linaro.org>
> Cc: Joao Pinto <jpinto@synopsys.com>
> Cc: Jose Abreu <jose.abreu@synopsys.com>
> Cc: Luis Oliveira <lolivei@synopsys.com>
> Cc: Vitor Soares <vitor.soares@synopsys.com>
> Cc: Nelson Costa <nelson.costa@synopsys.com>
> Cc: Pedro Sousa <pedrom.sousa@synopsys.com>

> +static struct dw_edma_chunk *dw_edma_alloc_chunk(struct dw_edma_desc *desc)
> +{
> + struct dw_edma_chan *chan = desc->chan;
> + struct dw_edma *dw = chan->chip->dw;
> + struct dw_edma_chunk *chunk;
> +
> + chunk = kvzalloc(sizeof(*chunk), GFP_NOWAIT);
> + if (unlikely(!chunk))
> + return NULL;
> +
> + INIT_LIST_HEAD(&chunk->list);
> + chunk->chan = chan;
> + chunk->cb = !(desc->chunks_alloc % 2);
> + chunk->ll_region.paddr = dw->ll_region.paddr + chan->ll_off;
> + chunk->ll_region.vaddr = dw->ll_region.vaddr + chan->ll_off;
> +
> + if (desc->chunk) {
> + /* Create and add new element into the linked list */
> + desc->chunks_alloc++;
> + dev_dbg(chan2dev(chan), "alloc new chunk element (%d)\n",
> + desc->chunks_alloc);
> + list_add_tail(&chunk->list, &desc->chunk->list);
> + dw_edma_alloc_burst(chunk);

No return check ?

> + } else {
> + /* List head */
> + chunk->burst = NULL;
> + desc->chunks_alloc = 0;
> + desc->chunk = chunk;
> + dev_dbg(chan2dev(chan), "alloc new chunk head\n");
> + }
> +
> + return chunk;
> +}
> +
> +static struct dw_edma_desc *dw_edma_alloc_desc(struct dw_edma_chan *chan)
> +{
> + struct dw_edma_desc *desc;
> +
> + dev_dbg(chan2dev(chan), "alloc new descriptor\n");
> +
> + desc = kvzalloc(sizeof(*desc), GFP_NOWAIT);
> + if (unlikely(!desc))
> + return NULL;
> +
> + desc->chan = chan;
> + dw_edma_alloc_chunk(desc);

No return check ?

> +
> + return desc;
> +}
> +

> +static void dw_edma_start_transfer(struct dw_edma_chan *chan)
> +{
> + struct virt_dma_desc *vd;
> + struct dw_edma_desc *desc;
> + struct dw_edma_chunk *child;
> + const struct dw_edma_core_ops *ops = chan2ops(chan);

Reverse tree order here and in remaining functions ...

> +
> + vd = vchan_next_desc(&chan->vc);
> + if (!vd)
> + return;
> +
> + desc = vd2dw_edma_desc(vd);
> + if (!desc)
> + return;
> +
> + child = list_first_entry_or_null(&desc->chunk->list,
> + struct dw_edma_chunk, list);
> + if (!child)
> + return;
> +
> + ops->start(child, !desc->xfer_sz);
> + desc->xfer_sz += child->ll_region.sz;
> + dev_dbg(chan2dev(chan), "transfer of %u bytes started\n",
> + child->ll_region.sz);
> +
> + dw_edma_free_burst(child);
> + if (child->bursts_alloc)
> + dev_dbg(chan2dev(chan), "%u bursts still allocated\n",
> + child->bursts_alloc);
> + list_del(&child->list);
> + kvfree(child);
> + desc->chunks_alloc--;
> +}
> +

> +int dw_edma_probe(struct dw_edma_chip *chip)
> +{
> + struct dw_edma *dw = chip->dw;
> + struct device *dev = chip->dev;
> + const struct dw_edma_core_ops *ops;
> + size_t ll_chunk = dw->ll_region.sz;
> + size_t dt_chunk = dw->dt_region.sz;
> + u32 ch_tot;
> + int i, j, err;
> +
> + raw_spin_lock_init(&dw->lock);

Why raw ?

> +
> + /* Callback operation selection accordingly to eDMA version */
> + switch (dw->version) {
> + default:
> + dev_err(dev, "unsupported version\n");
> + return -EPERM;
> + }
> +
> + pm_runtime_get_sync(dev);

Why do you need to increase usage count at probe ? And shouldn't
this be after pm_runtime_enable() ?

> +
> + /* Find out how many write channels are supported by hardware */
> + dw->wr_ch_cnt = ops->ch_count(dw, EDMA_DIR_WRITE);
> + if (!dw->wr_ch_cnt) {
> + dev_err(dev, "invalid number of write channels(0)\n");
> + return -EINVAL;
> + }
> +
> + /* Find out how many read channels are supported by hardware */
> + dw->rd_ch_cnt = ops->ch_count(dw, EDMA_DIR_READ);
> + if (!dw->rd_ch_cnt) {
> + dev_err(dev, "invalid number of read channels(0)\n");
> + return -EINVAL;
> + }
> +
> + dev_dbg(dev, "Channels:\twrite=%d, read=%d\n",
> + dw->wr_ch_cnt, dw->rd_ch_cnt);
> +
> + ch_tot = dw->wr_ch_cnt + dw->rd_ch_cnt;
> +
> + /* Allocate channels */
> + dw->chan = devm_kcalloc(dev, ch_tot, sizeof(*dw->chan), GFP_KERNEL);
> + if (!dw->chan)
> + return -ENOMEM;
> +
> + /* Calculate the linked list chunk for each channel */
> + ll_chunk /= roundup_pow_of_two(ch_tot);
> +
> + /* Calculate the linked list chunk for each channel */
> + dt_chunk /= roundup_pow_of_two(ch_tot);
> +
> + /* Disable eDMA, only to establish the ideal initial conditions */
> + ops->off(dw);
> +
> + snprintf(dw->name, sizeof(dw->name), "dw-edma-core:%d", chip->id);
> +
> + /* Request IRQs */
> + if (dw->nr_irqs != 1) {
> + dev_err(dev, "invalid number of irqs (%u)\n", dw->nr_irqs);
> + return -EINVAL;
> + }
> +
> + for (i = 0; i < dw->nr_irqs; i++) {
> + err = devm_request_irq(dev, pci_irq_vector(to_pci_dev(dev), i),
> + dw_edma_interrupt_all,
> + IRQF_SHARED, dw->name, chip);
> + if (err)
> + return err;
> + }
> +
> + /* Create write channels */
> + INIT_LIST_HEAD(&dw->wr_edma.channels);
> + for (i = 0; i < dw->wr_ch_cnt; i++) {
> + struct dw_edma_chan *chan = &dw->chan[i];
> + struct dw_edma_region *dt_region;
> +
> + dt_region = devm_kzalloc(dev, sizeof(*dt_region), GFP_KERNEL);
> + if (!dt_region)
> + return -ENOMEM;
> +
> + chan->vc.chan.private = dt_region;
> +
> + chan->chip = chip;
> + chan->id = i;
> + chan->dir = EDMA_DIR_WRITE;
> + chan->configured = false;
> + chan->request = EDMA_REQ_NONE;
> + chan->status = EDMA_ST_IDLE;
> +
> + chan->ll_off = (ll_chunk * i);
> + chan->ll_max = (ll_chunk / EDMA_LL_SZ) - 1;
> +
> + chan->dt_off = (dt_chunk * i);
> +
> + dev_dbg(dev, "L. List:\tChannel write[%u] off=0x%.8lx, max_cnt=%u\n",
> + i, chan->ll_off, chan->ll_max);
> +
> + memcpy(&chan->msi, &dw->msi[0], sizeof(chan->msi));
> +
> + dev_dbg(dev, "MSI:\t\tChannel write[%u] addr=0x%.8x%.8x, data=0x%.8x\n",
> + i, chan->msi.address_hi, chan->msi.address_lo,
> + chan->msi.data);
> +
> + chan->vc.desc_free = vchan_free_desc;
> + vchan_init(&chan->vc, &dw->wr_edma);
> +
> + dt_region->paddr = dw->dt_region.paddr + chan->dt_off;
> + dt_region->vaddr = dw->dt_region.vaddr + chan->dt_off;
> + dt_region->sz = dt_chunk;
> +
> + dev_dbg(dev, "Data:\tChannel write[%u] off=0x%.8lx\n",
> + i, chan->dt_off);
> + }
> + dma_cap_zero(dw->wr_edma.cap_mask);
> + dma_cap_set(DMA_SLAVE, dw->wr_edma.cap_mask);
> + dma_cap_set(DMA_CYCLIC, dw->wr_edma.cap_mask);
> + dw->wr_edma.directions = BIT(DMA_DEV_TO_MEM);
> + dw->wr_edma.chancnt = dw->wr_ch_cnt;
> +
> + /* Create read channels */
> + INIT_LIST_HEAD(&dw->rd_edma.channels);
> + for (j = 0; j < dw->rd_ch_cnt; j++, i++) {
> + struct dw_edma_chan *chan = &dw->chan[i];
> + struct dw_edma_region *dt_region;
> +
> + dt_region = devm_kzalloc(dev, sizeof(*dt_region), GFP_KERNEL);
> + if (!dt_region)
> + return -ENOMEM;
> +
> + chan->vc.chan.private = dt_region;
> +
> + chan->chip = chip;
> + chan->id = j;
> + chan->dir = EDMA_DIR_READ;
> + chan->configured = false;
> + chan->request = EDMA_REQ_NONE;
> + chan->status = EDMA_ST_IDLE;
> +
> + chan->ll_off = (ll_chunk * i);
> + chan->ll_max = (ll_chunk / EDMA_LL_SZ) - 1;
> +
> + chan->dt_off = (dt_chunk * i);
> +
> + dev_dbg(dev, "L. List:\tChannel read[%u] off=0x%.8lx, max_cnt=%u\n",
> + j, chan->ll_off, chan->ll_max);
> +
> + memcpy(&chan->msi, &dw->msi[0], sizeof(chan->msi));
> +
> + dev_dbg(dev, "MSI:\t\tChannel read[%u] addr=0x%.8x%.8x, data=0x%.8x\n",
> + j, chan->msi.address_hi, chan->msi.address_lo,
> + chan->msi.data);
> +
> + chan->vc.desc_free = vchan_free_desc;
> + vchan_init(&chan->vc, &dw->rd_edma);
> +
> + dt_region->paddr = dw->dt_region.paddr + chan->dt_off;
> + dt_region->vaddr = dw->dt_region.vaddr + chan->dt_off;
> + dt_region->sz = dt_chunk;
> +
> + dev_dbg(dev, "Data:\tChannel read[%u] off=0x%.8lx\n",
> + i, chan->dt_off);
> + }
> + dma_cap_zero(dw->rd_edma.cap_mask);
> + dma_cap_set(DMA_SLAVE, dw->rd_edma.cap_mask);
> + dma_cap_set(DMA_CYCLIC, dw->rd_edma.cap_mask);
> + dw->rd_edma.directions = BIT(DMA_MEM_TO_DEV);
> + dw->rd_edma.chancnt = dw->rd_ch_cnt;
> +
> + /* Set DMA channels capabilities */
> + SET_BOTH_CH(src_addr_widths, BIT(DMA_SLAVE_BUSWIDTH_4_BYTES));
> + SET_BOTH_CH(dst_addr_widths, BIT(DMA_SLAVE_BUSWIDTH_4_BYTES));
> + SET_BOTH_CH(residue_granularity, DMA_RESIDUE_GRANULARITY_DESCRIPTOR);
> +
> + SET_BOTH_CH(dev, dev);
> +
> + SET_BOTH_CH(device_alloc_chan_resources, dw_edma_alloc_chan_resources);
> + SET_BOTH_CH(device_free_chan_resources, dw_edma_free_chan_resources);
> +
> + SET_BOTH_CH(device_config, dw_edma_device_config);
> + SET_BOTH_CH(device_pause, dw_edma_device_pause);
> + SET_BOTH_CH(device_resume, dw_edma_device_resume);
> + SET_BOTH_CH(device_terminate_all, dw_edma_device_terminate_all);
> + SET_BOTH_CH(device_issue_pending, dw_edma_device_issue_pending);
> + SET_BOTH_CH(device_tx_status, dw_edma_device_tx_status);
> + SET_BOTH_CH(device_prep_slave_sg, dw_edma_device_prep_slave_sg);
> + SET_BOTH_CH(device_prep_dma_cyclic, dw_edma_device_prep_dma_cyclic);
> +
> + /* Power management */
> + pm_runtime_enable(dev);
> +
> + /* Register DMA device */
> + err = dma_async_device_register(&dw->wr_edma);
> + if (err)
> + goto err_pm_disable;
> +
> + err = dma_async_device_register(&dw->rd_edma);
> + if (err)
> + goto err_pm_disable;
> +
> + /* Turn debugfs on */
> + err = ops->debugfs_on(chip);
> + if (err) {
> + dev_err(dev, "unable to create debugfs structure\n");
> + goto err_pm_disable;
> + }
> +
> + dev_info(dev, "DesignWare eDMA controller driver loaded completely\n");
> +
> + return 0;
> +
> +err_pm_disable:
> + pm_runtime_disable(dev);
> +
> + return err;
> +}
> +EXPORT_SYMBOL_GPL(dw_edma_probe);
> +
> +int dw_edma_remove(struct dw_edma_chip *chip)
> +{
> + struct dw_edma *dw = chip->dw;
> + struct device *dev = chip->dev;
> + const struct dw_edma_core_ops *ops = dw->ops;
> + struct dw_edma_chan *chan, *_chan;
> + int i;
> +
> + /* Disable eDMA */
> + if (ops)
> + ops->off(dw);
> +
> + /* Free irqs */

But devm will automatically free it, no ?

> + for (i = 0; i < dw->nr_irqs; i++) {
> + if (pci_irq_vector(to_pci_dev(dev), i) < 0)
> + continue;
> +
> + devm_free_irq(dev, pci_irq_vector(to_pci_dev(dev), i), chip);
> + }
> +
> + /* Power management */
> + pm_runtime_disable(dev);
> +
> + list_for_each_entry_safe(chan, _chan, &dw->wr_edma.channels,
> + vc.chan.device_node) {
> + list_del(&chan->vc.chan.device_node);
> + tasklet_kill(&chan->vc.task);
> + }
> +
> + list_for_each_entry_safe(chan, _chan, &dw->rd_edma.channels,
> + vc.chan.device_node) {
> + list_del(&chan->vc.chan.device_node);
> + tasklet_kill(&chan->vc.task);
> + }
> +
> + /* Deregister eDMA device */
> + dma_async_device_unregister(&dw->wr_edma);
> + dma_async_device_unregister(&dw->rd_edma);
> +
> + /* Turn debugfs off */
> + if (ops)
> + ops->debugfs_off();
> +
> + dev_info(dev, "DesignWare eDMA controller driver unloaded complete\n");
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(dw_edma_remove);