Add support for processing the command rings. Command ring is used by the
host to issue channel specific commands to the ep device. Following
commands are supported:
1. Start channel
2. Stop channel
3. Reset channel
Once the device receives the command doorbell interrupt from host, it
executes the command and generates a command completion event to the
host in the primary event ring.
Reviewed-by: Alex Elder <elder@xxxxxxxxxx>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
---
drivers/bus/mhi/ep/main.c | 190 +++++++++++++++++++++++++++++++++++++-
include/linux/mhi_ep.h | 2 +
2 files changed, 191 insertions(+), 1 deletion(-)
diff --git a/drivers/bus/mhi/ep/main.c b/drivers/bus/mhi/ep/main.c
index 706473ea4918..32ac567e0f67 100644
--- a/drivers/bus/mhi/ep/main.c
+++ b/drivers/bus/mhi/ep/main.c
@@ -22,6 +22,7 @@
static DEFINE_IDA(mhi_ep_cntrl_ida);
+static int mhi_ep_create_device(struct mhi_ep_cntrl *mhi_cntrl, u32 ch_id);
static int mhi_ep_destroy_device(struct device *dev, void *data);
static int mhi_ep_send_event(struct mhi_ep_cntrl *mhi_cntrl, u32 ring_idx,
@@ -111,6 +112,156 @@ static int mhi_ep_send_cmd_comp_event(struct mhi_ep_cntrl *mhi_cntrl, enum mhi_e
return mhi_ep_send_event(mhi_cntrl, 0, &event, 0);
}
+static int mhi_ep_process_cmd_ring(struct mhi_ep_ring *ring, struct mhi_ring_element *el)
+{
+ struct mhi_ep_cntrl *mhi_cntrl = ring->mhi_cntrl;
+ struct device *dev = &mhi_cntrl->mhi_dev->dev;
+ struct mhi_result result = {};
+ struct mhi_ep_chan *mhi_chan;
+ struct mhi_ep_ring *ch_ring;
+ u32 tmp, ch_id;
+ int ret;
+
+ ch_id = MHI_TRE_GET_CMD_CHID(el);
+ mhi_chan = &mhi_cntrl->mhi_chan[ch_id];
+ ch_ring = &mhi_cntrl->mhi_chan[ch_id].ring;
+
+ switch (MHI_TRE_GET_CMD_TYPE(el)) {
+ case MHI_PKT_TYPE_START_CHAN_CMD:
+ dev_dbg(dev, "Received START command for channel (%u)\n", ch_id);
+
+ mutex_lock(&mhi_chan->lock);
+ /* Initialize and configure the corresponding channel ring */
+ if (!ch_ring->started) {
+ ret = mhi_ep_ring_start(mhi_cntrl, ch_ring,
+ (union mhi_ep_ring_ctx *)&mhi_cntrl->ch_ctx_cache[ch_id]);
+ if (ret) {
+ dev_err(dev, "Failed to start ring for channel (%u)\n", ch_id);
+ ret = mhi_ep_send_cmd_comp_event(mhi_cntrl,
+ MHI_EV_CC_UNDEFINED_ERR);
+ if (ret)
+ dev_err(dev, "Error sending completion event: %d\n", ret);
+
+ goto err_unlock;
+ }
+ }
+
+ /* Set channel state to RUNNING */
+ mhi_chan->state = MHI_CH_STATE_RUNNING;
+ tmp = le32_to_cpu(mhi_cntrl->ch_ctx_cache[ch_id].chcfg);
+ tmp &= ~CHAN_CTX_CHSTATE_MASK;
+ tmp |= FIELD_PREP(CHAN_CTX_CHSTATE_MASK, MHI_CH_STATE_RUNNING);
+ mhi_cntrl->ch_ctx_cache[ch_id].chcfg = cpu_to_le32(tmp);
+
+ ret = mhi_ep_send_cmd_comp_event(mhi_cntrl, MHI_EV_CC_SUCCESS);
+ if (ret) {
+ dev_err(dev, "Error sending command completion event (%u)\n",
+ MHI_EV_CC_SUCCESS);
+ goto err_unlock;
+ }
+
+ mutex_unlock(&mhi_chan->lock);
+
+ /*
+ * Create MHI device only during UL channel start. Since the MHI
+ * channels operate in a pair, we'll associate both UL and DL
+ * channels to the same device.
+ *
+ * We also need to check for mhi_dev != NULL because, the host
+ * will issue START_CHAN command during resume and we don't
+ * destroy the device during suspend.
+ */
+ if (!(ch_id % 2) && !mhi_chan->mhi_dev) {
+ ret = mhi_ep_create_device(mhi_cntrl, ch_id);
+ if (ret) {
+ dev_err(dev, "Error creating device for channel (%u)\n", ch_id);
+ mhi_ep_handle_syserr(mhi_cntrl);
+ return ret;
+ }
+ }
+
+ /* Finally, enable DB for the channel */
+ mhi_ep_mmio_enable_chdb(mhi_cntrl, ch_id);
+
+ break;
+ case MHI_PKT_TYPE_STOP_CHAN_CMD:
+ dev_dbg(dev, "Received STOP command for channel (%u)\n", ch_id);
+ if (!ch_ring->started) {
+ dev_err(dev, "Channel (%u) not opened\n", ch_id);
+ return -ENODEV;
+ }
+
+ mutex_lock(&mhi_chan->lock);
+ /* Disable DB for the channel */
+ mhi_ep_mmio_disable_chdb(mhi_cntrl, ch_id);
+
+ /* Send channel disconnect status to client drivers */
+ result.transaction_status = -ENOTCONN;
+ result.bytes_xferd = 0;
+ mhi_chan->xfer_cb(mhi_chan->mhi_dev, &result);
+
+ /* Set channel state to STOP */
+ mhi_chan->state = MHI_CH_STATE_STOP;
+ tmp = le32_to_cpu(mhi_cntrl->ch_ctx_cache[ch_id].chcfg);
+ tmp &= ~CHAN_CTX_CHSTATE_MASK;
+ tmp |= FIELD_PREP(CHAN_CTX_CHSTATE_MASK, MHI_CH_STATE_STOP);
+ mhi_cntrl->ch_ctx_cache[ch_id].chcfg = cpu_to_le32(tmp);
+
+ ret = mhi_ep_send_cmd_comp_event(mhi_cntrl, MHI_EV_CC_SUCCESS);
+ if (ret) {
+ dev_err(dev, "Error sending command completion event (%u)\n",
+ MHI_EV_CC_SUCCESS);
+ goto err_unlock;
+ }
+
+ mutex_unlock(&mhi_chan->lock);
+ break;
+ case MHI_PKT_TYPE_RESET_CHAN_CMD:
+ dev_dbg(dev, "Received STOP command for channel (%u)\n", ch_id);
+ if (!ch_ring->started) {
+ dev_err(dev, "Channel (%u) not opened\n", ch_id);
+ return -ENODEV;
+ }
+
+ mutex_lock(&mhi_chan->lock);
+ /* Stop and reset the transfer ring */
+ mhi_ep_ring_reset(mhi_cntrl, ch_ring);
+
+ /* Send channel disconnect status to client driver */
+ result.transaction_status = -ENOTCONN;
+ result.bytes_xferd = 0;
+ mhi_chan->xfer_cb(mhi_chan->mhi_dev, &result);
+
+ /* Set channel state to DISABLED */
+ mhi_chan->state = MHI_CH_STATE_DISABLED;
+ tmp = le32_to_cpu(mhi_cntrl->ch_ctx_cache[ch_id].chcfg);
+ tmp &= ~CHAN_CTX_CHSTATE_MASK;
+ tmp |= FIELD_PREP(CHAN_CTX_CHSTATE_MASK, MHI_CH_STATE_DISABLED);
+ mhi_cntrl->ch_ctx_cache[ch_id].chcfg = cpu_to_le32(tmp);
+
+ ret = mhi_ep_send_cmd_comp_event(mhi_cntrl, MHI_EV_CC_SUCCESS);
+ if (ret) {
+ dev_err(dev, "Error sending command completion event (%u)\n",
+ MHI_EV_CC_SUCCESS);
+ goto err_unlock;
+ }
+
+ mutex_unlock(&mhi_chan->lock);
+ break;
+ default:
+ dev_err(dev, "Invalid command received: %lu for channel (%u)\n",
+ MHI_TRE_GET_CMD_TYPE(el), ch_id);
+ return -EINVAL;
+ }
+
+ return 0;
+
+err_unlock:
+ mutex_unlock(&mhi_chan->lock);
+
+ return ret;
+}
+
static int mhi_ep_cache_host_cfg(struct mhi_ep_cntrl *mhi_cntrl)
{
size_t cmd_ctx_host_size, ch_ctx_host_size, ev_ctx_host_size;
@@ -259,6 +410,40 @@ static int mhi_ep_enable(struct mhi_ep_cntrl *mhi_cntrl)
return 0;
}
+static void mhi_ep_cmd_ring_worker(struct work_struct *work)
+{
+ struct mhi_ep_cntrl *mhi_cntrl = container_of(work, struct mhi_ep_cntrl, cmd_ring_work);
+ struct mhi_ep_ring *ring = &mhi_cntrl->mhi_cmd->ring;
+ struct device *dev = &mhi_cntrl->mhi_dev->dev;
+ struct mhi_ring_element *el;
+ int ret;
+
+ /* Update the write offset for the ring */
+ ret = mhi_ep_update_wr_offset(ring);
+ if (ret) {
+ dev_err(dev, "Error updating write offset for ring\n");
+ return;
+ }
+
+ /* Sanity check to make sure there are elements in the ring */
+ if (ring->rd_offset == ring->wr_offset)
+ return;
+
+ /*
+ * Process command ring element till write offset. In case of an error, just try to
+ * process next element.
+ */
+ while (ring->rd_offset != ring->wr_offset) {
+ el = &ring->ring_cache[ring->rd_offset];
+
+ ret = mhi_ep_process_cmd_ring(ring, el);
+ if (ret)
+ dev_err(dev, "Error processing cmd ring element: %zu\n", ring->rd_offset);
+
+ mhi_ep_ring_inc_index(ring);
+ }
+}
+
static void mhi_ep_state_worker(struct work_struct *work)
{
struct mhi_ep_cntrl *mhi_cntrl = container_of(work, struct mhi_ep_cntrl, state_work);
@@ -402,8 +587,10 @@ static irqreturn_t mhi_ep_irq(int irq, void *data)
}
/* Check for command doorbell interrupt */
- if (FIELD_GET(MHI_CTRL_INT_STATUS_CRDB_MSK, int_value))
+ if (FIELD_GET(MHI_CTRL_INT_STATUS_CRDB_MSK, int_value)) {
dev_dbg(dev, "Processing command doorbell interrupt\n");
+ queue_work(mhi_cntrl->wq, &mhi_cntrl->cmd_ring_work);
+ }
/* Check for channel interrupts */
mhi_ep_check_channel_interrupt(mhi_cntrl);
@@ -811,6 +998,7 @@ int mhi_ep_register_controller(struct mhi_ep_cntrl *mhi_cntrl,
INIT_WORK(&mhi_cntrl->state_work, mhi_ep_state_worker);
INIT_WORK(&mhi_cntrl->reset_work, mhi_ep_reset_worker);
+ INIT_WORK(&mhi_cntrl->cmd_ring_work, mhi_ep_cmd_ring_worker);
mhi_cntrl->wq = alloc_workqueue("mhi_ep_wq", 0, 0);
if (!mhi_cntrl->wq) {
diff --git a/include/linux/mhi_ep.h b/include/linux/mhi_ep.h
index 2f31a54c205f..8c6406d9c51f 100644
--- a/include/linux/mhi_ep.h
+++ b/include/linux/mhi_ep.h
@@ -77,6 +77,7 @@ struct mhi_ep_db_info {
* @wq: Dedicated workqueue for handling rings and state changes
* @state_work: State transition worker
* @reset_work: Worker for MHI Endpoint reset
+ * @cmd_ring_work: Worker for processing command rings
* @raise_irq: CB function for raising IRQ to the host
* @alloc_map: CB function for allocating memory in endpoint for storing host context and mapping it
* @unmap_free: CB function to unmap and free the allocated memory in endpoint for storing host context
@@ -124,6 +125,7 @@ struct mhi_ep_cntrl {
struct workqueue_struct *wq;
struct work_struct state_work;
struct work_struct reset_work;
+ struct work_struct cmd_ring_work;
void (*raise_irq)(struct mhi_ep_cntrl *mhi_cntrl, u32 vector);
int (*alloc_map)(struct mhi_ep_cntrl *mhi_cntrl, u64 pci_addr, phys_addr_t *phys_ptr,
--
2.25.1
