[PATCH v3 20/25] bus: mhi: ep: Add support for processing command ring

Manivannan Sadhasivam
2022-02-12T18:23:43Z

Add support for processing the command ring. 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.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
---
drivers/bus/mhi/ep/main.c | 151 ++++++++++++++++++++++++++++++++++++++
1 file changed, 151 insertions(+)

diff --git a/drivers/bus/mhi/ep/main.c b/drivers/bus/mhi/ep/main.c
index 6378ac5c7e37..4c2ee517832c 100644
--- a/drivers/bus/mhi/ep/main.c
+++ b/drivers/bus/mhi/ep/main.c
@@ -21,6 +21,7 @@

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,
@@ -185,6 +186,156 @@ void mhi_ep_unmap_free(struct mhi_ep_cntrl *mhi_cntrl, u64 pci_addr, phys_addr_t
mhi_cntrl->free_addr(mhi_cntrl, phys - offset, virt - offset, size);
}

+int mhi_ep_process_cmd_ring(struct mhi_ep_ring *ring, struct mhi_ep_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 (%d)\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 (%d)\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",
+ MHI_EV_CC_UNDEFINED_ERR);
+
+ goto err_unlock;
+ }
+ }
+
+ /* Enable DB for the channel */
+ mhi_ep_mmio_enable_chdb_a7(mhi_cntrl, ch_id);
+
+ /* 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 (%d)\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 (%d)\n", ch_id);
+ return ret;
+ }
+ }
+
+ break;
+ case MHI_PKT_TYPE_STOP_CHAN_CMD:
+ dev_dbg(dev, "Received STOP command for channel (%d)\n", ch_id);
+ if (!ch_ring->started) {
+ dev_err(dev, "Channel (%d) not opened\n", ch_id);
+ return -ENODEV;
+ }
+
+ mutex_lock(&mhi_chan->lock);
+ /* Disable DB for the channel */
+ mhi_ep_mmio_disable_chdb_a7(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 (%d)\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 (%d)\n", ch_id);
+ if (!ch_ring->started) {
+ dev_err(dev, "Channel (%d) 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 (%d)\n",
+ MHI_EV_CC_SUCCESS);
+ goto err_unlock;
+ }
+
+ mutex_unlock(&mhi_chan->lock);
+ break;
+ default:
+ dev_err(dev, "Invalid command received: %d for channel (%d)\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)
{
struct device *dev = &mhi_cntrl->mhi_dev->dev;
--
2.25.1