Re: [PATCH V2 3/3] dma: add Qualcomm Technologies HIDMA channel driver

Andy Shevchenko
2015-11-03T10:11:02Z

On Mon, Nov 2, 2015 at 8:07 AM, Sinan Kaya <okaya@codeaurora.org> wrote:
> This patch adds support for hidma engine. The driver
> consists of two logical blocks. The DMA engine interface
> and the low-level interface. The hardware only supports
> memcpy/memset and this driver only support memcpy
> interface. HW and driver doesn't support slave interface.

> +/* Linux Foundation elects GPLv2 license only.
> + */

One line?

> +#include <linux/dmaengine.h>
> +#include <linux/dma-mapping.h>
> +#include <asm/dma.h>

Do you need this one explicitly?

> +#include <linux/err.h>
> +#include <linux/init.h>
> +#include <linux/interrupt.h>
> +#include <linux/list.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +#include <linux/spinlock.h>
> +#include <linux/of_dma.h>
> +#include <linux/property.h>
> +#include <linux/delay.h>
> +#include <linux/highmem.h>
> +#include <linux/io.h>
> +#include <linux/sched.h>
> +#include <linux/wait.h>
> +#include <linux/acpi.h>
> +#include <linux/irq.h>
> +#include <linux/atomic.h>
> +#include <linux/pm_runtime.h>

+ empty line?

> +#include <asm/div64.h>

+ empty line?

> +#include "dmaengine.h"
> +#include "qcom_hidma.h"
> +
> +/* Default idle time is 2 seconds. This parameter can
> + * be overridden by changing the following
> + * /sys/bus/platform/devices/QCOM8061:<xy>/power/autosuspend_delay_ms
> + * during kernel boot.
> + */

Block comments usually like
/*
* text
*/

> +#define AUTOSUSPEND_TIMEOUT 2000
> +
> +struct hidma_lldev;
> +
> +struct hidma_dev {
> + int evridx;
> + u32 nr_descriptors;
> +
> + struct hidma_lldev *lldev;
> + void __iomem *dev_trca;
> + void __iomem *dev_evca;
> +
> + /* used to protect the pending channel list*/
> + spinlock_t lock;
> + struct dma_device ddev;
> +};
> +
> +struct hidma_chan {
> + bool paused;
> + bool allocated;
> + char name[16];

So, do you need specific name? There is already one in struct dma_chan.

> + u32 dma_sig;
> +
> + /*
> + * active descriptor on this channel
> + * It is used by the DMA complete notification to
> + * locate the descriptor that initiated the transfer.
> + */
> + struct hidma_dev *dmadev;
> +
> + struct dma_chan chan;
> + struct list_head free;
> + struct list_head prepared;
> + struct list_head active;
> + struct list_head completed;
> +
> + /* Lock for this structure */
> + spinlock_t lock;
> +};
> +
> +struct hidma_desc {
> + struct dma_async_tx_descriptor desc;
> + /* link list node for this channel*/
> + struct list_head node;
> + u32 tre_ch;
> +};
> +
> +static inline
> +struct hidma_dev *to_hidma_dev(struct dma_device *dmadev)
> +{
> + return container_of(dmadev, struct hidma_dev, ddev);
> +}
> +
> +static inline
> +struct hidma_dev *to_hidma_dev_from_lldev(struct hidma_lldev **_lldevp)
> +{
> + return container_of(_lldevp, struct hidma_dev, lldev);
> +}
> +
> +static inline
> +struct hidma_chan *to_hidma_chan(struct dma_chan *dmach)
> +{
> + return container_of(dmach, struct hidma_chan, chan);
> +}
> +
> +static inline struct hidma_desc *
> +to_hidma_desc(struct dma_async_tx_descriptor *t)
> +{
> + return container_of(t, struct hidma_desc, desc);
> +}
> +
> +static void hidma_free(struct hidma_dev *dmadev)
> +{
> + dev_dbg(dmadev->ddev.dev, "free dmadev\n");
> + INIT_LIST_HEAD(&dmadev->ddev.channels);
> +}
> +
> +static unsigned int nr_desc_prm;
> +module_param(nr_desc_prm, uint, 0644);
> +MODULE_PARM_DESC(nr_desc_prm,
> + "number of descriptors (default: 0)");
> +
> +#define MAX_HIDMA_CHANNELS 64
> +static int event_channel_idx[MAX_HIDMA_CHANNELS] = {
> + [0 ... (MAX_HIDMA_CHANNELS - 1)] = -1};
> +static unsigned int num_event_channel_idx;
> +module_param_array_named(event_channel_idx, event_channel_idx, int,
> + &num_event_channel_idx, 0644);
> +MODULE_PARM_DESC(event_channel_idx,
> + "event channel index array for the notifications");
> +static atomic_t channel_ref_count;
> +
> +/* process completed descriptors */
> +static void hidma_process_completed(struct hidma_dev *mdma)
> +{
> + dma_cookie_t last_cookie = 0;
> + struct hidma_chan *mchan;
> + struct hidma_desc *mdesc;
> + struct dma_async_tx_descriptor *desc;
> + unsigned long irqflags;
> + LIST_HEAD(list);
> + struct dma_chan *dmach = NULL;
> +
> + list_for_each_entry(dmach, &mdma->ddev.channels,
> + device_node) {
> + mchan = to_hidma_chan(dmach);
> +
> + /* Get all completed descriptors */
> + spin_lock_irqsave(&mchan->lock, irqflags);
> + if (!list_empty(&mchan->completed))
> + list_splice_tail_init(&mchan->completed, &list);
> + spin_unlock_irqrestore(&mchan->lock, irqflags);
> +
> + if (list_empty(&list))
> + continue;

Redundant check. It's done in both list_for_each_entry() and
list_splice_tail_init().

> +
> + /* Execute callbacks and run dependencies */
> + list_for_each_entry(mdesc, &list, node) {
> + desc = &mdesc->desc;
> +
> + spin_lock_irqsave(&mchan->lock, irqflags);
> + dma_cookie_complete(desc);
> + spin_unlock_irqrestore(&mchan->lock, irqflags);
> +
> + if (desc->callback &&
> + (hidma_ll_status(mdma->lldev, mdesc->tre_ch)
> + == DMA_COMPLETE))
> + desc->callback(desc->callback_param);
> +
> + last_cookie = desc->cookie;
> + dma_run_dependencies(desc);
> + }
> +
> + /* Free descriptors */
> + spin_lock_irqsave(&mchan->lock, irqflags);
> + list_splice_tail_init(&list, &mchan->free);
> + spin_unlock_irqrestore(&mchan->lock, irqflags);
> + }
> +}
> +
> +/*
> + * Execute all queued DMA descriptors.
> + * This function is called either on the first transfer attempt in tx_submit
> + * or from the callback routine when one transfer is finished. It can only be
> + * called from a single location since both of places check active list to be
> + * empty and will immediately fill the active list while lock is held.
> + *
> + * Following requirements must be met while calling hidma_execute():
> + * a) mchan->lock is locked,
> + * b) mchan->active list contains multiple entries.
> + * c) pm protected
> + */
> +static int hidma_execute(struct hidma_chan *mchan)
> +{
> + struct hidma_dev *mdma = mchan->dmadev;
> + int rc;
> +
> + if (!hidma_ll_isenabled(mdma->lldev))
> + return -ENODEV;
> +
> + /* Start the transfer */
> + if (!list_empty(&mchan->active))
> + rc = hidma_ll_start(mdma->lldev);
> +
> + return 0;
> +}
> +
> +/*
> + * Called once for each submitted descriptor.
> + * PM is locked once for each descriptor that is currently
> + * in execution.
> + */
> +static void hidma_callback(void *data)
> +{
> + struct hidma_desc *mdesc = data;
> + struct hidma_chan *mchan = to_hidma_chan(mdesc->desc.chan);
> + unsigned long irqflags;
> + struct dma_device *ddev = mchan->chan.device;
> + struct hidma_dev *dmadev = to_hidma_dev(ddev);
> + bool queued = false;
> +
> + dev_dbg(dmadev->ddev.dev, "callback: data:0x%p\n", data);
> +
> + spin_lock_irqsave(&mchan->lock, irqflags);
> +
> + if (mdesc->node.next) {
> + /* Delete from the active list, add to completed list */
> + list_move_tail(&mdesc->node, &mchan->completed);
> + queued = true;
> + }
> + spin_unlock_irqrestore(&mchan->lock, irqflags);
> +
> + hidma_process_completed(dmadev);
> +
> + if (queued) {
> + pm_runtime_mark_last_busy(dmadev->ddev.dev);
> + pm_runtime_put_autosuspend(dmadev->ddev.dev);
> + }
> +}
> +
> +static int hidma_chan_init(struct hidma_dev *dmadev, u32 dma_sig)
> +{
> + struct hidma_chan *mchan;
> + struct dma_device *ddev;
> +
> + mchan = devm_kzalloc(dmadev->ddev.dev, sizeof(*mchan), GFP_KERNEL);
> + if (!mchan)
> + return -ENOMEM;
> +
> + ddev = &dmadev->ddev;
> + mchan->dma_sig = dma_sig;
> + mchan->dmadev = dmadev;
> + mchan->chan.device = ddev;
> + dma_cookie_init(&mchan->chan);
> +
> + INIT_LIST_HEAD(&mchan->free);
> + INIT_LIST_HEAD(&mchan->prepared);
> + INIT_LIST_HEAD(&mchan->active);
> + INIT_LIST_HEAD(&mchan->completed);
> +
> + spin_lock_init(&mchan->lock);
> + list_add_tail(&mchan->chan.device_node, &ddev->channels);
> + dmadev->ddev.chancnt++;
> + return 0;
> +}
> +
> +static void hidma_issue_pending(struct dma_chan *dmach)
> +{

Wrong. It should actually start the transfer. tx_submit() just puts
the descriptor to a queue.

> +}
> +
> +static enum dma_status hidma_tx_status(struct dma_chan *dmach,
> + dma_cookie_t cookie,
> + struct dma_tx_state *txstate)
> +{
> + enum dma_status ret;
> + unsigned long irqflags;
> + struct hidma_chan *mchan = to_hidma_chan(dmach);
> +
> + spin_lock_irqsave(&mchan->lock, irqflags);

So, what are you protecting here? paused member, right?

> + if (mchan->paused)
> + ret = DMA_PAUSED;
> + else
> + ret = dma_cookie_status(dmach, cookie, txstate);

This one has no need to be under spin lock.

> + spin_unlock_irqrestore(&mchan->lock, irqflags);
> +
> + return ret;
> +}
> +
> +/*
> + * Submit descriptor to hardware.
> + * Lock the PM for each descriptor we are sending.
> + */
> +static dma_cookie_t hidma_tx_submit(struct dma_async_tx_descriptor *txd)
> +{
> + struct hidma_chan *mchan = to_hidma_chan(txd->chan);
> + struct hidma_dev *dmadev = mchan->dmadev;
> + struct hidma_desc *mdesc;
> + unsigned long irqflags;
> + dma_cookie_t cookie;
> +
> + if (!hidma_ll_isenabled(dmadev->lldev))
> + return -ENODEV;
> +
> + pm_runtime_get_sync(dmadev->ddev.dev);

No point to do it here. It should be done on the function that
actually starts the transfer (see issue pending).

> + mdesc = container_of(txd, struct hidma_desc, desc);
> + spin_lock_irqsave(&mchan->lock, irqflags);
> +
> + /* Move descriptor to active */
> + list_move_tail(&mdesc->node, &mchan->active);
> +
> + /* Update cookie */
> + cookie = dma_cookie_assign(txd);
> +
> + hidma_ll_queue_request(dmadev->lldev, mdesc->tre_ch);
> + hidma_execute(mchan);
> +
> + spin_unlock_irqrestore(&mchan->lock, irqflags);
> +
> + return cookie;
> +}
> +
> +static int hidma_alloc_chan_resources(struct dma_chan *dmach)
> +{
> + struct hidma_chan *mchan = to_hidma_chan(dmach);
> + struct hidma_dev *dmadev = mchan->dmadev;
> + int rc = 0;
> + struct hidma_desc *mdesc, *tmp;
> + unsigned long irqflags;
> + LIST_HEAD(descs);
> + u32 i;
> +
> + if (mchan->allocated)
> + return 0;
> +
> + /* Alloc descriptors for this channel */
> + for (i = 0; i < dmadev->nr_descriptors; i++) {
> + mdesc = kzalloc(sizeof(struct hidma_desc), GFP_KERNEL);
> + if (!mdesc) {
> + dev_err(dmadev->ddev.dev, "Memory allocation error. ");
> + rc = -ENOMEM;
> + break;
> + }
> + dma_async_tx_descriptor_init(&mdesc->desc, dmach);
> + mdesc->desc.flags = DMA_CTRL_ACK;
> + mdesc->desc.tx_submit = hidma_tx_submit;
> +
> + rc = hidma_ll_request(dmadev->lldev,
> + mchan->dma_sig, "DMA engine", hidma_callback,
> + mdesc, &mdesc->tre_ch);
> + if (rc != 1) {

if (rc < 1) {

> + dev_err(dmach->device->dev,
> + "channel alloc failed at %u\n", i);

> + kfree(mdesc);
> + break;
> + }
> + list_add_tail(&mdesc->node, &descs);
> + }
> +
> + if (rc != 1) {

if (rc < 1)

> + /* return the allocated descriptors */
> + list_for_each_entry_safe(mdesc, tmp, &descs, node) {
> + hidma_ll_free(dmadev->lldev, mdesc->tre_ch);
> + kfree(mdesc);
> + }
> + return rc;
> + }
> +
> + spin_lock_irqsave(&mchan->lock, irqflags);
> + list_splice_tail_init(&descs, &mchan->free);
> + mchan->allocated = true;
> + spin_unlock_irqrestore(&mchan->lock, irqflags);
> + dev_dbg(dmadev->ddev.dev,
> + "allocated channel for %u\n", mchan->dma_sig);
> + return rc;
> +}
> +
> +static void hidma_free_chan_resources(struct dma_chan *dmach)
> +{
> + struct hidma_chan *mchan = to_hidma_chan(dmach);
> + struct hidma_dev *mdma = mchan->dmadev;
> + struct hidma_desc *mdesc, *tmp;
> + unsigned long irqflags;
> + LIST_HEAD(descs);
> +
> + if (!list_empty(&mchan->prepared) ||
> + !list_empty(&mchan->active) ||
> + !list_empty(&mchan->completed)) {
> + /* We have unfinished requests waiting.
> + * Terminate the request from the hardware.
> + */
> + hidma_cleanup_pending_tre(mdma->lldev, 0x77, 0x77);

0x77 is magic.

> +
> + /* Give enough time for completions to be called. */
> + msleep(100);
> + }
> +
> + spin_lock_irqsave(&mchan->lock, irqflags);
> + /* Channel must be idle */
> + WARN_ON(!list_empty(&mchan->prepared));
> + WARN_ON(!list_empty(&mchan->active));
> + WARN_ON(!list_empty(&mchan->completed));
> +
> + /* Move data */
> + list_splice_tail_init(&mchan->free, &descs);
> +
> + /* Free descriptors */
> + list_for_each_entry_safe(mdesc, tmp, &descs, node) {
> + hidma_ll_free(mdma->lldev, mdesc->tre_ch);
> + list_del(&mdesc->node);
> + kfree(mdesc);
> + }
> +
> + mchan->allocated = 0;
> + spin_unlock_irqrestore(&mchan->lock, irqflags);
> + dev_dbg(mdma->ddev.dev, "freed channel for %u\n", mchan->dma_sig);
> +}
> +
> +
> +static struct dma_async_tx_descriptor *
> +hidma_prep_dma_memcpy(struct dma_chan *dmach, dma_addr_t dma_dest,
> + dma_addr_t dma_src, size_t len, unsigned long flags)
> +{
> + struct hidma_chan *mchan = to_hidma_chan(dmach);
> + struct hidma_desc *mdesc = NULL;
> + struct hidma_dev *mdma = mchan->dmadev;
> + unsigned long irqflags;
> +
> + dev_dbg(mdma->ddev.dev,
> + "memcpy: chan:%p dest:%pad src:%pad len:%zu\n", mchan,
> + &dma_dest, &dma_src, len);
> +
> + /* Get free descriptor */
> + spin_lock_irqsave(&mchan->lock, irqflags);
> + if (!list_empty(&mchan->free)) {
> + mdesc = list_first_entry(&mchan->free, struct hidma_desc,
> + node);
> + list_del(&mdesc->node);
> + }
> + spin_unlock_irqrestore(&mchan->lock, irqflags);
> +
> + if (!mdesc)
> + return NULL;
> +
> + hidma_ll_set_transfer_params(mdma->lldev, mdesc->tre_ch,
> + dma_src, dma_dest, len, flags);
> +
> + /* Place descriptor in prepared list */
> + spin_lock_irqsave(&mchan->lock, irqflags);
> + list_add_tail(&mdesc->node, &mchan->prepared);
> + spin_unlock_irqrestore(&mchan->lock, irqflags);
> +
> + return &mdesc->desc;
> +}
> +
> +static int hidma_terminate_all(struct dma_chan *chan)
> +{
> + struct hidma_dev *dmadev;
> + LIST_HEAD(head);
> + unsigned long irqflags;
> + LIST_HEAD(list);
> + struct hidma_desc *tmp, *mdesc = NULL;
> + int rc = 0;

Useless assignment.

> + struct hidma_chan *mchan;
> +
> + mchan = to_hidma_chan(chan);
> + dmadev = to_hidma_dev(mchan->chan.device);
> + dev_dbg(dmadev->ddev.dev, "terminateall: chan:0x%p\n", mchan);
> +
> + pm_runtime_get_sync(dmadev->ddev.dev);
> + /* give completed requests a chance to finish */
> + hidma_process_completed(dmadev);
> +
> + spin_lock_irqsave(&mchan->lock, irqflags);
> + list_splice_init(&mchan->active, &list);
> + list_splice_init(&mchan->prepared, &list);
> + list_splice_init(&mchan->completed, &list);
> + spin_unlock_irqrestore(&mchan->lock, irqflags);
> +
> + /* this suspends the existing transfer */
> + rc = hidma_ll_pause(dmadev->lldev);
> + if (rc) {
> + dev_err(dmadev->ddev.dev, "channel did not pause\n");
> + goto out;
> + }
> +
> + /* return all user requests */
> + list_for_each_entry_safe(mdesc, tmp, &list, node) {
> + struct dma_async_tx_descriptor *txd = &mdesc->desc;
> + dma_async_tx_callback callback = mdesc->desc.callback;
> + void *param = mdesc->desc.callback_param;
> + enum dma_status status;
> +
> + dma_descriptor_unmap(txd);
> +
> + status = hidma_ll_status(dmadev->lldev, mdesc->tre_ch);
> + /*
> + * The API requires that no submissions are done from a
> + * callback, so we don't need to drop the lock here
> + */
> + if (callback && (status == DMA_COMPLETE))
> + callback(param);
> +
> + dma_run_dependencies(txd);
> +
> + /* move myself to free_list */
> + list_move(&mdesc->node, &mchan->free);
> + }
> +
> + /* reinitialize the hardware */
> + rc = hidma_ll_setup(dmadev->lldev);
> +
> +out:
> + pm_runtime_mark_last_busy(dmadev->ddev.dev);
> + pm_runtime_put_autosuspend(dmadev->ddev.dev);
> + return rc;
> +}
> +
> +static int hidma_pause(struct dma_chan *chan)
> +{
> + struct hidma_chan *mchan;
> + struct hidma_dev *dmadev;
> +
> + mchan = to_hidma_chan(chan);
> + dmadev = to_hidma_dev(mchan->chan.device);
> + dev_dbg(dmadev->ddev.dev, "pause: chan:0x%p\n", mchan);
> +
> + pm_runtime_get_sync(dmadev->ddev.dev);

Why it's here? Here is nothing to do with the device, move it to _pause().

> + if (!mchan->paused) {
> + if (hidma_ll_pause(dmadev->lldev))
> + dev_warn(dmadev->ddev.dev, "channel did not stop\n");
> + mchan->paused = true;
> + }
> + pm_runtime_mark_last_busy(dmadev->ddev.dev);
> + pm_runtime_put_autosuspend(dmadev->ddev.dev);
> + return 0;
> +}
> +
> +static int hidma_resume(struct dma_chan *chan)
> +{
> + struct hidma_chan *mchan;
> + struct hidma_dev *dmadev;
> + int rc = 0;
> +
> + mchan = to_hidma_chan(chan);
> + dmadev = to_hidma_dev(mchan->chan.device);
> + dev_dbg(dmadev->ddev.dev, "resume: chan:0x%p\n", mchan);
> +
> + pm_runtime_get_sync(dmadev->ddev.dev);

Ditto.

> + if (mchan->paused) {
> + rc = hidma_ll_resume(dmadev->lldev);
> + if (!rc)
> + mchan->paused = false;
> + else
> + dev_err(dmadev->ddev.dev,
> + "failed to resume the channel");
> + }
> + pm_runtime_mark_last_busy(dmadev->ddev.dev);
> + pm_runtime_put_autosuspend(dmadev->ddev.dev);
> + return rc;
> +}
> +
> +static irqreturn_t hidma_chirq_handler(int chirq, void *arg)
> +{
> + struct hidma_lldev **lldev_ptr = arg;
> + irqreturn_t ret;
> + struct hidma_dev *dmadev = to_hidma_dev_from_lldev(lldev_ptr);
> +
> + pm_runtime_get_sync(dmadev->ddev.dev);

Hmm... Do you have shared IRQ line or wakeup able one?
Otherwise I can't see ways how device can generate interrupts.
If there is a case other than described, put comment why it might happen.

> + ret = hidma_ll_inthandler(chirq, *lldev_ptr);
> + pm_runtime_mark_last_busy(dmadev->ddev.dev);
> + pm_runtime_put_autosuspend(dmadev->ddev.dev);
> + return ret;
> +}
> +
> +static int hidma_probe(struct platform_device *pdev)
> +{
> + struct hidma_dev *dmadev;
> + int rc = 0;
> + struct resource *trca_resource;
> + struct resource *evca_resource;
> + int chirq;
> + int current_channel_index = atomic_read(&channel_ref_count);
> +
> + pm_runtime_set_autosuspend_delay(&pdev->dev, AUTOSUSPEND_TIMEOUT);
> + pm_runtime_use_autosuspend(&pdev->dev);
> + pm_runtime_set_active(&pdev->dev);
> + pm_runtime_enable(&pdev->dev);
> +
> + trca_resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!trca_resource) {
> + rc = -ENODEV;
> + goto bailout;
> + }
> +
> + evca_resource = platform_get_resource(pdev, IORESOURCE_MEM, 1);
> + if (!evca_resource) {
> + rc = -ENODEV;
> + goto bailout;
> + }

Consolidate these with devm_ioremap_resource();

> +
> + /* This driver only handles the channel IRQs.
> + * Common IRQ is handled by the management driver.
> + */
> + chirq = platform_get_irq(pdev, 0);
> + if (chirq < 0) {
> + rc = -ENODEV;
> + goto bailout;
> + }
> +
> + dmadev = devm_kzalloc(&pdev->dev, sizeof(*dmadev), GFP_KERNEL);
> + if (!dmadev) {
> + rc = -ENOMEM;
> + goto bailout;
> + }
> +
> + INIT_LIST_HEAD(&dmadev->ddev.channels);
> + spin_lock_init(&dmadev->lock);
> + dmadev->ddev.dev = &pdev->dev;
> + pm_runtime_get_sync(dmadev->ddev.dev);
> +
> + dma_cap_set(DMA_MEMCPY, dmadev->ddev.cap_mask);
> + if (WARN_ON(!pdev->dev.dma_mask)) {
> + rc = -ENXIO;
> + goto dmafree;
> + }
> +
> + dmadev->dev_evca = devm_ioremap_resource(&pdev->dev,
> + evca_resource);
> + if (IS_ERR(dmadev->dev_evca)) {
> + rc = -ENOMEM;
> + goto dmafree;
> + }
> +
> + dmadev->dev_trca = devm_ioremap_resource(&pdev->dev,
> + trca_resource);
> + if (IS_ERR(dmadev->dev_trca)) {
> + rc = -ENOMEM;
> + goto dmafree;
> + }
> + dmadev->ddev.device_prep_dma_memcpy = hidma_prep_dma_memcpy;
> + dmadev->ddev.device_alloc_chan_resources =
> + hidma_alloc_chan_resources;
> + dmadev->ddev.device_free_chan_resources = hidma_free_chan_resources;
> + dmadev->ddev.device_tx_status = hidma_tx_status;
> + dmadev->ddev.device_issue_pending = hidma_issue_pending;
> + dmadev->ddev.device_pause = hidma_pause;
> + dmadev->ddev.device_resume = hidma_resume;
> + dmadev->ddev.device_terminate_all = hidma_terminate_all;
> + dmadev->ddev.copy_align = 8;
> +
> + device_property_read_u32(&pdev->dev, "desc-count",
> + &dmadev->nr_descriptors);
> +
> + if (!dmadev->nr_descriptors && nr_desc_prm)
> + dmadev->nr_descriptors = nr_desc_prm;
> +
> + if (!dmadev->nr_descriptors)
> + goto dmafree;
> +
> + if (current_channel_index > MAX_HIDMA_CHANNELS)
> + goto dmafree;
> +
> + dmadev->evridx = -1;
> + device_property_read_u32(&pdev->dev, "event-channel", &dmadev->evridx);
> +
> + /* kernel command line override for the guest machine */
> + if (event_channel_idx[current_channel_index] != -1)
> + dmadev->evridx = event_channel_idx[current_channel_index];
> +
> + if (dmadev->evridx == -1)
> + goto dmafree;
> +
> + /* Set DMA mask to 64 bits. */
> + rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
> + if (rc) {
> + dev_warn(&pdev->dev, "unable to set coherent mask to 64");
> + rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
> + }
> + if (rc)
> + goto dmafree;
> +
> + dmadev->lldev = hidma_ll_init(dmadev->ddev.dev,
> + dmadev->nr_descriptors, dmadev->dev_trca,
> + dmadev->dev_evca, dmadev->evridx);
> + if (!dmadev->lldev) {
> + rc = -EPROBE_DEFER;
> + goto dmafree;
> + }
> +
> + rc = devm_request_irq(&pdev->dev, chirq, hidma_chirq_handler, 0,
> + "qcom-hidma", &dmadev->lldev);

Better to use request_irq().

> + if (rc)
> + goto uninit;
> +
> + INIT_LIST_HEAD(&dmadev->ddev.channels);
> + rc = hidma_chan_init(dmadev, 0);
> + if (rc)
> + goto uninit;
> +
> + rc = dma_selftest_memcpy(&dmadev->ddev);
> + if (rc)
> + goto uninit;
> +
> + rc = dma_async_device_register(&dmadev->ddev);
> + if (rc)
> + goto uninit;
> +
> + dev_info(&pdev->dev, "HI-DMA engine driver registration complete\n");
> + platform_set_drvdata(pdev, dmadev);
> + pm_runtime_mark_last_busy(dmadev->ddev.dev);
> + pm_runtime_put_autosuspend(dmadev->ddev.dev);
> + atomic_inc(&channel_ref_count);
> + return 0;
> +
> +uninit:
> + hidma_ll_uninit(dmadev->lldev);
> +dmafree:
> + if (dmadev)
> + hidma_free(dmadev);
> +bailout:
> + pm_runtime_disable(&pdev->dev);
> + pm_runtime_put_sync_suspend(&pdev->dev);
> + return rc;
> +}
> +
> +static int hidma_remove(struct platform_device *pdev)
> +{
> + struct hidma_dev *dmadev = platform_get_drvdata(pdev);
> +
> + dev_dbg(&pdev->dev, "removing\n");
> + pm_runtime_get_sync(dmadev->ddev.dev);
> +
> + dma_async_device_unregister(&dmadev->ddev);
> + hidma_ll_uninit(dmadev->lldev);
> + hidma_free(dmadev);
> +
> + dev_info(&pdev->dev, "HI-DMA engine removed\n");
> + pm_runtime_put_sync_suspend(&pdev->dev);
> + pm_runtime_disable(&pdev->dev);
> +
> + return 0;
> +}
> +
> +#if IS_ENABLED(CONFIG_ACPI)
> +static const struct acpi_device_id hidma_acpi_ids[] = {
> + {"QCOM8061"},
> + {},
> +};
> +#endif
> +
> +static const struct of_device_id hidma_match[] = {
> + { .compatible = "qcom,hidma-1.0", },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, hidma_match);
> +
> +static struct platform_driver hidma_driver = {
> + .probe = hidma_probe,
> + .remove = hidma_remove,
> + .driver = {
> + .name = "hidma",
> + .of_match_table = hidma_match,
> + .acpi_match_table = ACPI_PTR(hidma_acpi_ids),
> + },
> +};
> +module_platform_driver(hidma_driver);
> +MODULE_LICENSE("GPL v2");
> diff --git a/drivers/dma/qcom_hidma.h b/drivers/dma/qcom_hidma.h
> new file mode 100644
> index 0000000..d671b39
> --- /dev/null
> +++ b/drivers/dma/qcom_hidma.h
> @@ -0,0 +1,45 @@
> +/*
> + * Qualcomm Technologies HIDMA data structures
> + *
> + * Copyright (c) 2014, The Linux Foundation. All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 and
> + * only version 2 as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + */
> +
> +#ifndef QCOM_HIDMA_H
> +#define QCOM_HIDMA_H
> +
> +struct hidma_lldev;
> +struct hidma_llchan;
> +struct seq_file;
> +struct hidma_lldev;
> +
> +int hidma_ll_request(struct hidma_lldev *llhndl, u32 dev_id,
> + const char *dev_name,
> + void (*callback)(void *data), void *data, u32 *tre_ch);
> +
> +void hidma_ll_free(struct hidma_lldev *llhndl, u32 tre_ch);
> +enum dma_status hidma_ll_status(struct hidma_lldev *llhndl, u32 tre_ch);
> +bool hidma_ll_isenabled(struct hidma_lldev *llhndl);
> +int hidma_ll_queue_request(struct hidma_lldev *llhndl, u32 tre_ch);
> +int hidma_ll_start(struct hidma_lldev *llhndl);
> +int hidma_ll_pause(struct hidma_lldev *llhndl);
> +int hidma_ll_resume(struct hidma_lldev *llhndl);
> +void hidma_ll_set_transfer_params(struct hidma_lldev *llhndl, u32 tre_ch,
> + dma_addr_t src, dma_addr_t dest, u32 len, u32 flags);
> +int hidma_ll_setup(struct hidma_lldev *lldev);
> +struct hidma_lldev *hidma_ll_init(struct device *dev, u32 max_channels,
> + void __iomem *trca, void __iomem *evca,
> + u8 evridx);
> +int hidma_ll_uninit(struct hidma_lldev *llhndl);
> +irqreturn_t hidma_ll_inthandler(int irq, void *arg);
> +void hidma_cleanup_pending_tre(struct hidma_lldev *llhndl, u8 err_info,
> + u8 err_code);
> +#endif
> diff --git a/drivers/dma/qcom_hidma_ll.c b/drivers/dma/qcom_hidma_ll.c
> new file mode 100644
> index 0000000..1e8b4aa
> --- /dev/null
> +++ b/drivers/dma/qcom_hidma_ll.c
> @@ -0,0 +1,972 @@
> +/*
> + * Qualcomm Technologies HIDMA DMA engine low level code
> + *
> + * Copyright (c) 2015, The Linux Foundation. All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 and
> + * only version 2 as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/dmaengine.h>
> +#include <linux/slab.h>
> +#include <linux/interrupt.h>
> +#include <linux/mm.h>
> +#include <linux/highmem.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/delay.h>
> +#include <linux/atomic.h>
> +#include <linux/iopoll.h>
> +#include "qcom_hidma.h"
> +
> +#define TRE_SIZE 32 /* each TRE is 32 bytes */
> +#define EVRE_SIZE 16 /* each EVRE is 16 bytes */
> +
> +#define TRCA_CTRLSTS_OFFSET 0x0
> +#define TRCA_RING_LOW_OFFSET 0x8
> +#define TRCA_RING_HIGH_OFFSET 0xC
> +#define TRCA_RING_LEN_OFFSET 0x10
> +#define TRCA_READ_PTR_OFFSET 0x18
> +#define TRCA_WRITE_PTR_OFFSET 0x20
> +#define TRCA_DOORBELL_OFFSET 0x400
> +
> +#define EVCA_CTRLSTS_OFFSET 0x0
> +#define EVCA_INTCTRL_OFFSET 0x4
> +#define EVCA_RING_LOW_OFFSET 0x8
> +#define EVCA_RING_HIGH_OFFSET 0xC
> +#define EVCA_RING_LEN_OFFSET 0x10
> +#define EVCA_READ_PTR_OFFSET 0x18
> +#define EVCA_WRITE_PTR_OFFSET 0x20
> +#define EVCA_DOORBELL_OFFSET 0x400
> +
> +#define EVCA_IRQ_STAT_OFFSET 0x100
> +#define EVCA_IRQ_CLR_OFFSET 0x108
> +#define EVCA_IRQ_EN_OFFSET 0x110
> +
> +#define TRE_CFG_IDX 0
> +#define TRE_LEN_IDX 1
> +#define TRE_SRC_LOW_IDX 2
> +#define TRE_SRC_HI_IDX 3
> +#define TRE_DEST_LOW_IDX 4
> +#define TRE_DEST_HI_IDX 5
> +
> +#define EVRE_CFG_IDX 0
> +#define EVRE_LEN_IDX 1
> +#define EVRE_DEST_LOW_IDX 2
> +#define EVRE_DEST_HI_IDX 3
> +
> +#define EVRE_ERRINFO_BIT_POS 24
> +#define EVRE_CODE_BIT_POS 28
> +
> +#define EVRE_ERRINFO_MASK 0xF
> +#define EVRE_CODE_MASK 0xF
> +
> +#define CH_CONTROL_MASK 0xFF
> +#define CH_STATE_MASK 0xFF
> +#define CH_STATE_BIT_POS 0x8
> +
> +#define MAKE64(high, low) (((u64)(high) << 32) | (low))
> +
> +#define IRQ_EV_CH_EOB_IRQ_BIT_POS 0
> +#define IRQ_EV_CH_WR_RESP_BIT_POS 1
> +#define IRQ_TR_CH_TRE_RD_RSP_ER_BIT_POS 9
> +#define IRQ_TR_CH_DATA_RD_ER_BIT_POS 10
> +#define IRQ_TR_CH_DATA_WR_ER_BIT_POS 11
> +#define IRQ_TR_CH_INVALID_TRE_BIT_POS 14
> +
> +#define ENABLE_IRQS (BIT(IRQ_EV_CH_EOB_IRQ_BIT_POS) | \
> + BIT(IRQ_EV_CH_WR_RESP_BIT_POS) | \
> + BIT(IRQ_TR_CH_TRE_RD_RSP_ER_BIT_POS) | \
> + BIT(IRQ_TR_CH_DATA_RD_ER_BIT_POS) | \
> + BIT(IRQ_TR_CH_DATA_WR_ER_BIT_POS) | \
> + BIT(IRQ_TR_CH_INVALID_TRE_BIT_POS))
> +
> +enum ch_command {
> + CH_DISABLE = 0,
> + CH_ENABLE = 1,
> + CH_SUSPEND = 2,
> + CH_RESET = 9,
> +};
> +
> +enum ch_state {
> + CH_DISABLED = 0,
> + CH_ENABLED = 1,
> + CH_RUNNING = 2,
> + CH_SUSPENDED = 3,
> + CH_STOPPED = 4,
> + CH_ERROR = 5,
> + CH_IN_RESET = 9,
> +};
> +
> +enum tre_type {
> + TRE_MEMCPY = 3,
> + TRE_MEMSET = 4,
> +};
> +
> +enum evre_type {
> + EVRE_DMA_COMPLETE = 0x23,
> + EVRE_IMM_DATA = 0x24,
> +};
> +
> +enum err_code {
> + EVRE_STATUS_COMPLETE = 1,
> + EVRE_STATUS_ERROR = 4,
> +};
> +
> +struct hidma_tx_status {
> + u8 err_info; /* error record in this transfer */
> + u8 err_code; /* completion code */
> +};
> +
> +struct hidma_lldev {
> + bool initialized; /* initialized flag */
> + u8 trch_state; /* trch_state of the device */
> + u8 evch_state; /* evch_state of the device */
> + u8 evridx; /* event channel to notify */
> + u32 nr_tres; /* max number of configs */
> + spinlock_t lock; /* reentrancy */
> + struct hidma_tre *trepool; /* trepool of user configs */
> + struct device *dev; /* device */
> + void __iomem *trca; /* Transfer Channel address */
> + void __iomem *evca; /* Event Channel address */
> + struct hidma_tre
> + **pending_tre_list; /* Pointers to pending TREs */
> + struct hidma_tx_status
> + *tx_status_list; /* Pointers to pending TREs status*/
> + s32 pending_tre_count; /* Number of TREs pending */
> +
> + void *tre_ring; /* TRE ring */
> + dma_addr_t tre_ring_handle; /* TRE ring to be shared with HW */
> + u32 tre_ring_size; /* Byte size of the ring */
> + u32 tre_processed_off; /* last processed TRE */
> +
> + void *evre_ring; /* EVRE ring */
> + dma_addr_t evre_ring_handle; /* EVRE ring to be shared with HW */
> + u32 evre_ring_size; /* Byte size of the ring */
> + u32 evre_processed_off; /* last processed EVRE */
> +
> + u32 tre_write_offset; /* TRE write location */
> +};
> +
> +struct hidma_tre {
> + atomic_t allocated; /* if this channel is allocated */
> + bool queued; /* flag whether this is pending */
> + u16 status; /* status */
> + u32 chidx; /* index of the tre */
> + u32 dma_sig; /* signature of the tre */
> + const char *dev_name; /* name of the device */
> + void (*callback)(void *data); /* requester callback */
> + void *data; /* Data associated with this channel*/
> + struct hidma_lldev *lldev; /* lldma device pointer */
> + u32 tre_local[TRE_SIZE / sizeof(u32) + 1]; /* TRE local copy */
> + struct tasklet_struct task; /* task delivering notifications */
> + u32 tre_index; /* the offset where this was written*/
> + u32 int_flags; /* interrupt flags*/
> +};
> +
> +void hidma_ll_free(struct hidma_lldev *lldev, u32 tre_ch)
> +{
> + struct hidma_tre *tre;
> +
> + if (tre_ch >= lldev->nr_tres) {
> + dev_err(lldev->dev, "invalid TRE number in free:%d", tre_ch);
> + return;
> + }
> +
> + tre = &lldev->trepool[tre_ch];
> + if (atomic_read(&tre->allocated) != true) {
> + dev_err(lldev->dev, "trying to free an unused TRE:%d",
> + tre_ch);
> + return;
> + }
> +
> + atomic_set(&tre->allocated, 0);
> + dev_dbg(lldev->dev, "free_dma: allocated:%d tre_ch:%d\n",
> + atomic_read(&tre->allocated), tre_ch);
> +}
> +
> +int hidma_ll_request(struct hidma_lldev *lldev, u32 dma_sig,
> + const char *dev_name,
> + void (*callback)(void *data), void *data, u32 *tre_ch)
> +{
> + u32 i;
> + struct hidma_tre *tre = NULL;
> + u32 *tre_local;
> +
> + if (!tre_ch || !lldev)
> + return -EINVAL;
> +
> + /* need to have at least one empty spot in the queue */
> + for (i = 0; i < lldev->nr_tres - 1; i++) {
> + if (atomic_add_unless(&lldev->trepool[i].allocated, 1, 1))
> + break;
> + }
> +
> + if (i == (lldev->nr_tres - 1))
> + return -ENOMEM;
> +
> + tre = &lldev->trepool[i];
> + tre->dma_sig = dma_sig;
> + tre->dev_name = dev_name;
> + tre->callback = callback;
> + tre->data = data;
> + tre->chidx = i;
> + tre->status = 0;
> + tre->queued = 0;
> + lldev->tx_status_list[i].err_code = 0;
> + tre->lldev = lldev;
> + tre_local = &tre->tre_local[0];
> + tre_local[TRE_CFG_IDX] = TRE_MEMCPY;
> + tre_local[TRE_CFG_IDX] |= ((lldev->evridx & 0xFF) << 8);
> + tre_local[TRE_CFG_IDX] |= BIT(16); /* set IEOB */
> + *tre_ch = i;
> + if (callback)
> + callback(data);
> + return 1;
> +}
> +
> +/*
> + * Multiple TREs may be queued and waiting in the
> + * pending queue.
> + */
> +static void hidma_ll_tre_complete(unsigned long arg)
> +{
> + struct hidma_tre *tre = (struct hidma_tre *)arg;
> +
> + /* call the user if it has been read by the hardware*/
> + if (tre->callback)
> + tre->callback(tre->data);
> +}
> +
> +/*
> + * Called to handle the interrupt for the channel.
> + * Return a positive number if TRE or EVRE were consumed on this run.
> + * Return a positive number if there are pending TREs or EVREs.
> + * Return 0 if there is nothing to consume or no pending TREs/EVREs found.
> + */
> +static int hidma_handle_tre_completion(struct hidma_lldev *lldev)
> +{
> + struct hidma_tre *tre;
> + u32 evre_write_off;
> + u32 evre_ring_size = lldev->evre_ring_size;
> + u32 tre_ring_size = lldev->tre_ring_size;
> + u32 num_completed = 0, tre_iterator, evre_iterator;
> + unsigned long flags;
> +
> + evre_write_off = readl_relaxed(lldev->evca + EVCA_WRITE_PTR_OFFSET);
> + tre_iterator = lldev->tre_processed_off;
> + evre_iterator = lldev->evre_processed_off;
> +
> + if ((evre_write_off > evre_ring_size) ||
> + ((evre_write_off % EVRE_SIZE) != 0)) {
> + dev_err(lldev->dev, "HW reports invalid EVRE write offset\n");
> + return 0;
> + }
> +
> + /* By the time control reaches here the number of EVREs and TREs
> + * may not match. Only consume the ones that hardware told us.
> + */
> + while ((evre_iterator != evre_write_off)) {
> + u32 *current_evre = lldev->evre_ring + evre_iterator;
> + u32 cfg;
> + u8 err_info;
> +
> + spin_lock_irqsave(&lldev->lock, flags);
> + tre = lldev->pending_tre_list[tre_iterator / TRE_SIZE];
> + if (!tre) {
> + spin_unlock_irqrestore(&lldev->lock, flags);
> + dev_warn(lldev->dev,
> + "tre_index [%d] and tre out of sync\n",
> + tre_iterator / TRE_SIZE);
> + tre_iterator += TRE_SIZE;
> + if (tre_iterator >= tre_ring_size)
> + tre_iterator -= tre_ring_size;
> + evre_iterator += EVRE_SIZE;
> + if (evre_iterator >= evre_ring_size)
> + evre_iterator -= evre_ring_size;
> +
> + continue;
> + }
> + lldev->pending_tre_list[tre->tre_index] = NULL;
> +
> + /* Keep track of pending TREs that SW is expecting to receive
> + * from HW. We got one now. Decrement our counter.
> + */
> + lldev->pending_tre_count--;
> + if (lldev->pending_tre_count < 0) {
> + dev_warn(lldev->dev,
> + "tre count mismatch on completion");
> + lldev->pending_tre_count = 0;
> + }
> +
> + spin_unlock_irqrestore(&lldev->lock, flags);
> +
> + cfg = current_evre[EVRE_CFG_IDX];
> + err_info = (cfg >> EVRE_ERRINFO_BIT_POS);
> + err_info = err_info & EVRE_ERRINFO_MASK;
> + lldev->tx_status_list[tre->chidx].err_info = err_info;
> + lldev->tx_status_list[tre->chidx].err_code =
> + (cfg >> EVRE_CODE_BIT_POS) & EVRE_CODE_MASK;
> + tre->queued = 0;
> +
> + tasklet_schedule(&tre->task);
> +
> + tre_iterator += TRE_SIZE;
> + if (tre_iterator >= tre_ring_size)
> + tre_iterator -= tre_ring_size;
> + evre_iterator += EVRE_SIZE;
> + if (evre_iterator >= evre_ring_size)
> + evre_iterator -= evre_ring_size;
> +
> + /* Read the new event descriptor written by the HW.
> + * As we are processing the delivered events, other events
> + * get queued to the SW for processing.
> + */
> + evre_write_off =
> + readl_relaxed(lldev->evca + EVCA_WRITE_PTR_OFFSET);
> + num_completed++;
> + }
> +
> + if (num_completed) {
> + u32 evre_read_off = (lldev->evre_processed_off +
> + EVRE_SIZE * num_completed);
> + u32 tre_read_off = (lldev->tre_processed_off +
> + TRE_SIZE * num_completed);
> +
> + evre_read_off = evre_read_off % evre_ring_size;
> + tre_read_off = tre_read_off % tre_ring_size;
> +
> + writel(evre_read_off, lldev->evca + EVCA_DOORBELL_OFFSET);
> +
> + /* record the last processed tre offset */
> + lldev->tre_processed_off = tre_read_off;
> + lldev->evre_processed_off = evre_read_off;
> + }
> +
> + return num_completed;
> +}
> +
> +void hidma_cleanup_pending_tre(struct hidma_lldev *lldev, u8 err_info,
> + u8 err_code)
> +{
> + u32 tre_iterator;
> + struct hidma_tre *tre;
> + u32 tre_ring_size = lldev->tre_ring_size;
> + int num_completed = 0;
> + u32 tre_read_off;
> + unsigned long flags;
> +
> + tre_iterator = lldev->tre_processed_off;
> + while (lldev->pending_tre_count) {
> + int tre_index = tre_iterator / TRE_SIZE;
> +
> + spin_lock_irqsave(&lldev->lock, flags);
> + tre = lldev->pending_tre_list[tre_index];
> + if (!tre) {
> + spin_unlock_irqrestore(&lldev->lock, flags);
> + tre_iterator += TRE_SIZE;
> + if (tre_iterator >= tre_ring_size)
> + tre_iterator -= tre_ring_size;
> + continue;
> + }
> + lldev->pending_tre_list[tre_index] = NULL;
> + lldev->pending_tre_count--;
> + if (lldev->pending_tre_count < 0) {
> + dev_warn(lldev->dev,
> + "tre count mismatch on completion");
> + lldev->pending_tre_count = 0;
> + }
> + spin_unlock_irqrestore(&lldev->lock, flags);
> +
> + lldev->tx_status_list[tre->chidx].err_info = err_info;
> + lldev->tx_status_list[tre->chidx].err_code = err_code;
> + tre->queued = 0;
> +
> + tasklet_schedule(&tre->task);
> +
> + tre_iterator += TRE_SIZE;
> + if (tre_iterator >= tre_ring_size)
> + tre_iterator -= tre_ring_size;
> +
> + num_completed++;
> + }
> + tre_read_off = (lldev->tre_processed_off +
> + TRE_SIZE * num_completed);
> +
> + tre_read_off = tre_read_off % tre_ring_size;
> +
> + /* record the last processed tre offset */
> + lldev->tre_processed_off = tre_read_off;
> +}
> +
> +static int hidma_ll_reset(struct hidma_lldev *lldev)
> +{
> + u32 val;
> + int ret;
> +
> + val = readl_relaxed(lldev->trca + TRCA_CTRLSTS_OFFSET);
> + val = val & ~(CH_CONTROL_MASK << 16);
> + val = val | (CH_RESET << 16);
> + writel(val, lldev->trca + TRCA_CTRLSTS_OFFSET);
> +
> + /* Delay 10ms after reset to allow DMA logic to quiesce.
> + * Do a polled read up to 1ms and 10ms maximum.
> + */
> + ret = readl_poll_timeout(lldev->trca + TRCA_CTRLSTS_OFFSET, val,
> + (((val >> CH_STATE_BIT_POS) & CH_STATE_MASK) == CH_DISABLED),
> + 1000, 10000);
> + if (ret) {
> + dev_err(lldev->dev,
> + "transfer channel did not reset\n");
> + return ret;
> + }
> +
> + val = readl_relaxed(lldev->evca + EVCA_CTRLSTS_OFFSET);
> + val = val & ~(CH_CONTROL_MASK << 16);
> + val = val | (CH_RESET << 16);
> + writel(val, lldev->evca + EVCA_CTRLSTS_OFFSET);
> +
> + /* Delay 10ms after reset to allow DMA logic to quiesce.
> + * Do a polled read up to 1ms and 10ms maximum.
> + */
> + ret = readl_poll_timeout(lldev->evca + EVCA_CTRLSTS_OFFSET, val,
> + (((val >> CH_STATE_BIT_POS) & CH_STATE_MASK) == CH_DISABLED),
> + 1000, 10000);
> + if (ret)
> + return ret;
> +
> + lldev->trch_state = CH_DISABLED;
> + lldev->evch_state = CH_DISABLED;
> + return 0;
> +}
> +
> +static void hidma_ll_enable_irq(struct hidma_lldev *lldev, u32 irq_bits)
> +{
> + writel(irq_bits, lldev->evca + EVCA_IRQ_EN_OFFSET);
> + dev_dbg(lldev->dev, "enableirq\n");
> +}
> +
> +/*
> + * The interrupt handler for HIDMA will try to consume as many pending
> + * EVRE from the event queue as possible. Each EVRE has an associated
> + * TRE that holds the user interface parameters. EVRE reports the
> + * result of the transaction. Hardware guarantees ordering between EVREs
> + * and TREs. We use last processed offset to figure out which TRE is
> + * associated with which EVRE. If two TREs are consumed by HW, the EVREs
> + * are in order in the event ring.
> + * This handler will do a one pass for consuming EVREs. Other EVREs may
> + * be delivered while we are working. It will try to consume incoming
> + * EVREs one more time and return.
> + * For unprocessed EVREs, hardware will trigger another interrupt until
> + * all the interrupt bits are cleared.
> + *
> + * Hardware guarantees that by the time interrupt is observed, all data
> + * transactions in flight are delivered to their respective places and
> + * are visible to the CPU.
> + *
> + * On demand paging for IOMMU is only supported for PCIe via PRI
> + * (Page Request Interface) not for HIDMA. All other hardware instances
> + * including HIDMA work on pinned DMA addresses.
> + *
> + */
> +static void hidma_ll_int_handler_internal(struct hidma_lldev *lldev)
> +{
> + u32 status;
> + u32 enable;
> + u32 cause;
> + int repeat = 2;
> + unsigned long timeout;
> +
> + status = readl_relaxed(lldev->evca + EVCA_IRQ_STAT_OFFSET);
> + enable = readl_relaxed(lldev->evca + EVCA_IRQ_EN_OFFSET);
> + cause = status & enable;
> +
> + if ((cause & (BIT(IRQ_TR_CH_INVALID_TRE_BIT_POS))) ||
> + (cause & BIT(IRQ_TR_CH_TRE_RD_RSP_ER_BIT_POS)) ||
> + (cause & BIT(IRQ_EV_CH_WR_RESP_BIT_POS)) ||
> + (cause & BIT(IRQ_TR_CH_DATA_RD_ER_BIT_POS)) ||
> + (cause & BIT(IRQ_TR_CH_DATA_WR_ER_BIT_POS))) {
> + u8 err_code = EVRE_STATUS_ERROR;
> + u8 err_info = 0xFF;
> +
> + /* Clear out pending interrupts */
> + writel(cause, lldev->evca + EVCA_IRQ_CLR_OFFSET);
> +
> + dev_err(lldev->dev,
> + "error 0x%x, resetting...\n", cause);
> +
> + hidma_cleanup_pending_tre(lldev, err_info, err_code);
> +
> + /* reset the channel for recovery */
> + if (hidma_ll_setup(lldev)) {
> + dev_err(lldev->dev,
> + "channel reinitialize failed after error\n");
> + return;
> + }
> + hidma_ll_enable_irq(lldev, ENABLE_IRQS);
> + return;
> + }
> +
> + /* Try to consume as many EVREs as possible.
> + * skip this loop if the interrupt is spurious.
> + */
> + while (cause && repeat) {
> + unsigned long start = jiffies;
> +
> + /* This timeout should be sufficent for core to finish */
> + timeout = start + msecs_to_jiffies(500);
> +
> + while (lldev->pending_tre_count) {
> + hidma_handle_tre_completion(lldev);
> + if (time_is_before_jiffies(timeout)) {
> + dev_warn(lldev->dev,
> + "ISR timeout %lx-%lx from %lx [%d]\n",
> + jiffies, timeout, start,
> + lldev->pending_tre_count);
> + break;
> + }
> + }
> +
> + /* We consumed TREs or there are pending TREs or EVREs. */
> + writel_relaxed(cause, lldev->evca + EVCA_IRQ_CLR_OFFSET);
> +
> + /* Another interrupt might have arrived while we are
> + * processing this one. Read the new cause.
> + */
> + status = readl_relaxed(lldev->evca + EVCA_IRQ_STAT_OFFSET);
> + enable = readl_relaxed(lldev->evca + EVCA_IRQ_EN_OFFSET);
> + cause = status & enable;
> +
> + repeat--;
> + }
> +}
> +
> +
> +static int hidma_ll_enable(struct hidma_lldev *lldev)
> +{
> + u32 val;
> + int ret;
> +
> + val = readl_relaxed(lldev->evca + EVCA_CTRLSTS_OFFSET);
> + val &= ~(CH_CONTROL_MASK << 16);
> + val |= (CH_ENABLE << 16);
> + writel(val, lldev->evca + EVCA_CTRLSTS_OFFSET);
> +
> + ret = readl_poll_timeout(lldev->evca + EVCA_CTRLSTS_OFFSET, val,
> + ((((val >> CH_STATE_BIT_POS) & CH_STATE_MASK) == CH_ENABLED) ||
> + (((val >> CH_STATE_BIT_POS) & CH_STATE_MASK) == CH_RUNNING)),
> + 1000, 10000);
> + if (ret) {
> + dev_err(lldev->dev,
> + "event channel did not get enabled\n");
> + return ret;
> + }
> +
> + val = readl_relaxed(lldev->trca + TRCA_CTRLSTS_OFFSET);
> + val = val & ~(CH_CONTROL_MASK << 16);
> + val = val | (CH_ENABLE << 16);
> + writel(val, lldev->trca + TRCA_CTRLSTS_OFFSET);
> +
> + ret = readl_poll_timeout(lldev->trca + TRCA_CTRLSTS_OFFSET, val,
> + ((((val >> CH_STATE_BIT_POS) & CH_STATE_MASK) == CH_ENABLED) ||
> + (((val >> CH_STATE_BIT_POS) & CH_STATE_MASK) == CH_RUNNING)),
> + 1000, 10000);
> + if (ret) {
> + dev_err(lldev->dev,
> + "transfer channel did not get enabled\n");
> + return ret;
> + }
> +
> + lldev->trch_state = CH_ENABLED;
> + lldev->evch_state = CH_ENABLED;
> +
> + return 0;
> +}
> +
> +int hidma_ll_resume(struct hidma_lldev *lldev)
> +{
> + return hidma_ll_enable(lldev);
> +}
> +
> +static int hidma_ll_hw_start(struct hidma_lldev *lldev)
> +{
> + int rc = 0;
> + unsigned long irqflags;
> +
> + spin_lock_irqsave(&lldev->lock, irqflags);
> + writel(lldev->tre_write_offset, lldev->trca + TRCA_DOORBELL_OFFSET);
> + spin_unlock_irqrestore(&lldev->lock, irqflags);
> +
> + return rc;
> +}
> +
> +bool hidma_ll_isenabled(struct hidma_lldev *lldev)
> +{
> + u32 val;
> +
> + val = readl_relaxed(lldev->trca + TRCA_CTRLSTS_OFFSET);
> + lldev->trch_state = (val >> CH_STATE_BIT_POS) & CH_STATE_MASK;
> + val = readl_relaxed(lldev->evca + EVCA_CTRLSTS_OFFSET);
> + lldev->evch_state = (val >> CH_STATE_BIT_POS) & CH_STATE_MASK;
> +
> + /* both channels have to be enabled before calling this function*/
> + if (((lldev->trch_state == CH_ENABLED) ||
> + (lldev->trch_state == CH_RUNNING)) &&
> + ((lldev->evch_state == CH_ENABLED) ||
> + (lldev->evch_state == CH_RUNNING)))
> + return true;
> +
> + dev_dbg(lldev->dev, "channels are not enabled or are in error state");
> + return false;
> +}
> +
> +int hidma_ll_queue_request(struct hidma_lldev *lldev, u32 tre_ch)
> +{
> + struct hidma_tre *tre;
> + int rc = 0;
> + unsigned long flags;
> +
> + tre = &lldev->trepool[tre_ch];
> +
> + /* copy the TRE into its location in the TRE ring */
> + spin_lock_irqsave(&lldev->lock, flags);
> + tre->tre_index = lldev->tre_write_offset / TRE_SIZE;
> + lldev->pending_tre_list[tre->tre_index] = tre;
> + memcpy(lldev->tre_ring + lldev->tre_write_offset, &tre->tre_local[0],
> + TRE_SIZE);
> + lldev->tx_status_list[tre->chidx].err_code = 0;
> + lldev->tx_status_list[tre->chidx].err_info = 0;
> + tre->queued = 1;
> + lldev->pending_tre_count++;
> + lldev->tre_write_offset = (lldev->tre_write_offset + TRE_SIZE)
> + % lldev->tre_ring_size;
> + spin_unlock_irqrestore(&lldev->lock, flags);
> + return rc;
> +}
> +
> +int hidma_ll_start(struct hidma_lldev *lldev)
> +{
> + return hidma_ll_hw_start(lldev);
> +}
> +
> +/*
> + * Note that even though we stop this channel
> + * if there is a pending transaction in flight
> + * it will complete and follow the callback.
> + * This request will prevent further requests
> + * to be made.
> + */
> +int hidma_ll_pause(struct hidma_lldev *lldev)
> +{
> + u32 val;
> + int ret;
> +
> + val = readl_relaxed(lldev->evca + EVCA_CTRLSTS_OFFSET);
> + lldev->evch_state = (val >> CH_STATE_BIT_POS) & CH_STATE_MASK;
> + val = readl_relaxed(lldev->trca + TRCA_CTRLSTS_OFFSET);
> + lldev->trch_state = (val >> CH_STATE_BIT_POS) & CH_STATE_MASK;
> +
> + /* already suspended by this OS */
> + if ((lldev->trch_state == CH_SUSPENDED) ||
> + (lldev->evch_state == CH_SUSPENDED))
> + return 0;
> +
> + /* already stopped by the manager */
> + if ((lldev->trch_state == CH_STOPPED) ||
> + (lldev->evch_state == CH_STOPPED))
> + return 0;
> +
> + val = readl_relaxed(lldev->trca + TRCA_CTRLSTS_OFFSET);
> + val = val & ~(CH_CONTROL_MASK << 16);
> + val = val | (CH_SUSPEND << 16);
> + writel(val, lldev->trca + TRCA_CTRLSTS_OFFSET);
> +
> + /* Start the wait right after the suspend is confirmed.
> + * Do a polled read up to 1ms and 10ms maximum.
> + */
> + ret = readl_poll_timeout(lldev->trca + TRCA_CTRLSTS_OFFSET, val,
> + (((val >> CH_STATE_BIT_POS) & CH_STATE_MASK) == CH_SUSPENDED),
> + 1000, 10000);
> + if (ret)
> + return ret;
> +
> + val = readl_relaxed(lldev->evca + EVCA_CTRLSTS_OFFSET);
> + val = val & ~(CH_CONTROL_MASK << 16);
> + val = val | (CH_SUSPEND << 16);
> + writel(val, lldev->evca + EVCA_CTRLSTS_OFFSET);
> +
> + /* Start the wait right after the suspend is confirmed
> + * Delay up to 10ms after reset to allow DMA logic to quiesce.
> + */
> + ret = readl_poll_timeout(lldev->evca + EVCA_CTRLSTS_OFFSET, val,
> + (((val >> CH_STATE_BIT_POS) & CH_STATE_MASK) == CH_SUSPENDED),
> + 1000, 10000);
> + if (ret)
> + return ret;
> +
> + lldev->trch_state = CH_SUSPENDED;
> + lldev->evch_state = CH_SUSPENDED;
> + dev_dbg(lldev->dev, "stop\n");
> +
> + return 0;
> +}
> +
> +void hidma_ll_set_transfer_params(struct hidma_lldev *lldev, u32 tre_ch,
> + dma_addr_t src, dma_addr_t dest, u32 len, u32 flags)
> +{
> + struct hidma_tre *tre;
> + u32 *tre_local;
> +
> + if (tre_ch >= lldev->nr_tres) {
> + dev_err(lldev->dev,
> + "invalid TRE number in transfer params:%d", tre_ch);
> + return;
> + }
> +
> + tre = &lldev->trepool[tre_ch];
> + if (atomic_read(&tre->allocated) != true) {
> + dev_err(lldev->dev,
> + "trying to set params on an unused TRE:%d", tre_ch);
> + return;
> + }
> +
> + tre_local = &tre->tre_local[0];
> + tre_local[TRE_LEN_IDX] = len;
> + tre_local[TRE_SRC_LOW_IDX] = lower_32_bits(src);
> + tre_local[TRE_SRC_HI_IDX] = upper_32_bits(src);
> + tre_local[TRE_DEST_LOW_IDX] = lower_32_bits(dest);
> + tre_local[TRE_DEST_HI_IDX] = upper_32_bits(dest);
> + tre->int_flags = flags;
> +
> + dev_dbg(lldev->dev, "transferparams: tre_ch:%d %pap->%pap len:%u\n",
> + tre_ch, &src, &dest, len);
> +}
> +
> +/* Called during initialization and after an error condition
> + * to restore hardware state.
> + */
> +int hidma_ll_setup(struct hidma_lldev *lldev)
> +{
> + int rc;
> + u64 addr;
> + u32 val;
> + u32 nr_tres = lldev->nr_tres;
> +
> + lldev->pending_tre_count = 0;
> + lldev->tre_processed_off = 0;
> + lldev->evre_processed_off = 0;
> + lldev->tre_write_offset = 0;
> +
> + /* disable interrupts */
> + hidma_ll_enable_irq(lldev, 0);
> +
> + /* clear all pending interrupts */
> + val = readl_relaxed(lldev->evca + EVCA_IRQ_STAT_OFFSET);
> + writel_relaxed(val, lldev->evca + EVCA_IRQ_CLR_OFFSET);
> +
> + rc = hidma_ll_reset(lldev);
> + if (rc)
> + return rc;
> +
> + /* Clear all pending interrupts again.
> + * Otherwise, we observe reset complete interrupts.
> + */
> + val = readl_relaxed(lldev->evca + EVCA_IRQ_STAT_OFFSET);
> + writel_relaxed(val, lldev->evca + EVCA_IRQ_CLR_OFFSET);
> +
> + /* disable interrupts again after reset */
> + hidma_ll_enable_irq(lldev, 0);
> +
> + addr = lldev->tre_ring_handle;
> + writel_relaxed(lower_32_bits(addr),
> + lldev->trca + TRCA_RING_LOW_OFFSET);
> + writel_relaxed(upper_32_bits(addr),
> + lldev->trca + TRCA_RING_HIGH_OFFSET);
> + writel_relaxed(lldev->tre_ring_size,
> + lldev->trca + TRCA_RING_LEN_OFFSET);
> +
> + addr = lldev->evre_ring_handle;
> + writel_relaxed(lower_32_bits(addr),
> + lldev->evca + EVCA_RING_LOW_OFFSET);
> + writel_relaxed(upper_32_bits(addr),
> + lldev->evca + EVCA_RING_HIGH_OFFSET);
> + writel_relaxed(EVRE_SIZE * nr_tres,
> + lldev->evca + EVCA_RING_LEN_OFFSET);
> +
> + /* support IRQ only for now */
> + val = readl_relaxed(lldev->evca + EVCA_INTCTRL_OFFSET);
> + val = val & ~(0xF);
> + val = val | 0x1;
> + writel_relaxed(val, lldev->evca + EVCA_INTCTRL_OFFSET);
> +
> + /* clear all pending interrupts and enable them*/
> + writel_relaxed(ENABLE_IRQS, lldev->evca + EVCA_IRQ_CLR_OFFSET);
> + hidma_ll_enable_irq(lldev, ENABLE_IRQS);
> +
> + rc = hidma_ll_enable(lldev);
> + if (rc)
> + return rc;
> +
> + return rc;
> +}
> +
> +struct hidma_lldev *hidma_ll_init(struct device *dev, u32 nr_tres,
> + void __iomem *trca, void __iomem *evca,
> + u8 evridx)
> +{
> + u32 required_bytes;
> + struct hidma_lldev *lldev;
> + int rc;
> + u32 i;
> +
> + if (!trca || !evca || !dev || !nr_tres)
> + return NULL;
> +
> + /* need at least four TREs */
> + if (nr_tres < 4)
> + return NULL;
> +
> + /* need an extra space */
> + nr_tres += 1;
> +
> + lldev = devm_kzalloc(dev, sizeof(struct hidma_lldev), GFP_KERNEL);
> + if (!lldev)
> + return NULL;
> +
> + lldev->evca = evca;
> + lldev->trca = trca;
> + lldev->dev = dev;
> + required_bytes = sizeof(struct hidma_tre) * nr_tres;
> + lldev->trepool = devm_kzalloc(lldev->dev, required_bytes, GFP_KERNEL);
> + if (!lldev->trepool)
> + return NULL;
> +
> + required_bytes = sizeof(lldev->pending_tre_list[0]) * nr_tres;
> + lldev->pending_tre_list = devm_kzalloc(dev, required_bytes,
> + GFP_KERNEL);
> + if (!lldev->pending_tre_list)
> + return NULL;
> +
> + required_bytes = sizeof(lldev->tx_status_list[0]) * nr_tres;
> + lldev->tx_status_list = devm_kzalloc(dev, required_bytes, GFP_KERNEL);
> + if (!lldev->tx_status_list)
> + return NULL;
> +
> + lldev->tre_ring = dmam_alloc_coherent(dev, (TRE_SIZE + 1) * nr_tres,
> + &lldev->tre_ring_handle, GFP_KERNEL);
> + if (!lldev->tre_ring)
> + return NULL;
> +
> + memset(lldev->tre_ring, 0, (TRE_SIZE + 1) * nr_tres);
> + lldev->tre_ring_size = TRE_SIZE * nr_tres;
> + lldev->nr_tres = nr_tres;
> +
> + /* the TRE ring has to be TRE_SIZE aligned */
> + if (!IS_ALIGNED(lldev->tre_ring_handle, TRE_SIZE)) {
> + u8 tre_ring_shift;
> +
> + tre_ring_shift = lldev->tre_ring_handle % TRE_SIZE;
> + tre_ring_shift = TRE_SIZE - tre_ring_shift;
> + lldev->tre_ring_handle += tre_ring_shift;
> + lldev->tre_ring += tre_ring_shift;
> + }
> +
> + lldev->evre_ring = dmam_alloc_coherent(dev, (EVRE_SIZE + 1) * nr_tres,
> + &lldev->evre_ring_handle, GFP_KERNEL);
> + if (!lldev->evre_ring)
> + return NULL;
> +
> + memset(lldev->evre_ring, 0, (EVRE_SIZE + 1) * nr_tres);
> + lldev->evre_ring_size = EVRE_SIZE * nr_tres;
> +
> + /* the EVRE ring has to be EVRE_SIZE aligned */
> + if (!IS_ALIGNED(lldev->evre_ring_handle, EVRE_SIZE)) {
> + u8 evre_ring_shift;
> +
> + evre_ring_shift = lldev->evre_ring_handle % EVRE_SIZE;
> + evre_ring_shift = EVRE_SIZE - evre_ring_shift;
> + lldev->evre_ring_handle += evre_ring_shift;
> + lldev->evre_ring += evre_ring_shift;
> + }
> + lldev->nr_tres = nr_tres;
> + lldev->evridx = evridx;
> +
> + rc = hidma_ll_setup(lldev);
> + if (rc)
> + return NULL;
> +
> + spin_lock_init(&lldev->lock);
> + for (i = 0; i < nr_tres; i++)
> + tasklet_init(&lldev->trepool[i].task, hidma_ll_tre_complete,
> + (unsigned long)&lldev->trepool[i]);
> + lldev->initialized = 1;
> + hidma_ll_enable_irq(lldev, ENABLE_IRQS);
> + return lldev;
> +}
> +
> +int hidma_ll_uninit(struct hidma_lldev *lldev)
> +{
> + int rc = 0;
> + u32 val;
> +
> + if (!lldev)
> + return -ENODEV;
> +
> + if (lldev->initialized) {
> + u32 required_bytes;
> + u32 i;
> +
> + lldev->initialized = 0;
> +
> + required_bytes = sizeof(struct hidma_tre) * lldev->nr_tres;
> + for (i = 0; i < lldev->nr_tres; i++)
> + tasklet_kill(&lldev->trepool[i].task);
> + memset(lldev->trepool, 0, required_bytes);
> + lldev->trepool = NULL;
> + lldev->pending_tre_count = 0;
> + lldev->tre_write_offset = 0;
> +
> + rc = hidma_ll_reset(lldev);
> +
> + /* Clear all pending interrupts again.
> + * Otherwise, we observe reset complete interrupts.
> + */
> + val = readl_relaxed(lldev->evca + EVCA_IRQ_STAT_OFFSET);
> + writel_relaxed(val, lldev->evca + EVCA_IRQ_CLR_OFFSET);
> + hidma_ll_enable_irq(lldev, 0);
> + }
> + return rc;
> +}
> +
> +irqreturn_t hidma_ll_inthandler(int chirq, void *arg)
> +{
> + struct hidma_lldev *lldev = arg;
> +
> + hidma_ll_int_handler_internal(lldev);
> + return IRQ_HANDLED;
> +}
> +
> +enum dma_status hidma_ll_status(struct hidma_lldev *lldev, u32 tre_ch)
> +{
> + enum dma_status ret = DMA_ERROR;
> + unsigned long flags;
> + u8 err_code;
> +
> + spin_lock_irqsave(&lldev->lock, flags);
> + err_code = lldev->tx_status_list[tre_ch].err_code;
> +
> + if (err_code & EVRE_STATUS_COMPLETE)
> + ret = DMA_COMPLETE;
> + else if (err_code & EVRE_STATUS_ERROR)
> + ret = DMA_ERROR;
> + else
> + ret = DMA_IN_PROGRESS;
> + spin_unlock_irqrestore(&lldev->lock, flags);
> +
> + return ret;
> +}
> --
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> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project
>
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--
With Best Regards,
Andy Shevchenko