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authorManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>2021-11-29 14:19:29 +0530
committerManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>2022-04-04 10:17:50 +0530
commitb6c52d410cb464f5cc5d962b92205f7232cb18b8 (patch)
treea791c24cc13e6ea8b613488cfa6365522f77fa6d /drivers/bus
parentbus: mhi: ep: Add support for managing MHI state machine (diff)
downloadlinux-dev-b6c52d410cb464f5cc5d962b92205f7232cb18b8.tar.xz
linux-dev-b6c52d410cb464f5cc5d962b92205f7232cb18b8.zip
bus: mhi: ep: Add support for processing MHI endpoint interrupts
Add support for processing MHI endpoint interrupts such as control interrupt, command interrupt and channel interrupt from the host. The interrupts will be generated in the endpoint device whenever host writes to the corresponding doorbell registers. The doorbell logic is handled inside the hardware internally. Reviewed-by: Alex Elder <elder@linaro.org> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Diffstat (limited to 'drivers/bus')
-rw-r--r--drivers/bus/mhi/ep/main.c124
1 files changed, 122 insertions, 2 deletions
diff --git a/drivers/bus/mhi/ep/main.c b/drivers/bus/mhi/ep/main.c
index c912daf6dc65..4e82006bd83b 100644
--- a/drivers/bus/mhi/ep/main.c
+++ b/drivers/bus/mhi/ep/main.c
@@ -11,6 +11,7 @@
#include <linux/dma-direction.h>
#include <linux/interrupt.h>
#include <linux/io.h>
+#include <linux/irq.h>
#include <linux/mhi_ep.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
@@ -142,6 +143,112 @@ static void mhi_ep_state_worker(struct work_struct *work)
}
}
+static void mhi_ep_queue_channel_db(struct mhi_ep_cntrl *mhi_cntrl, unsigned long ch_int,
+ u32 ch_idx)
+{
+ struct mhi_ep_ring_item *item;
+ struct mhi_ep_ring *ring;
+ bool work = !!ch_int;
+ LIST_HEAD(head);
+ u32 i;
+
+ /* First add the ring items to a local list */
+ for_each_set_bit(i, &ch_int, 32) {
+ /* Channel index varies for each register: 0, 32, 64, 96 */
+ u32 ch_id = ch_idx + i;
+
+ ring = &mhi_cntrl->mhi_chan[ch_id].ring;
+ item = kzalloc(sizeof(*item), GFP_ATOMIC);
+ if (!item)
+ return;
+
+ item->ring = ring;
+ list_add_tail(&item->node, &head);
+ }
+
+ /* Now, splice the local list into ch_db_list and queue the work item */
+ if (work) {
+ spin_lock(&mhi_cntrl->list_lock);
+ list_splice_tail_init(&head, &mhi_cntrl->ch_db_list);
+ spin_unlock(&mhi_cntrl->list_lock);
+ }
+}
+
+/*
+ * Channel interrupt statuses are contained in 4 registers each of 32bit length.
+ * For checking all interrupts, we need to loop through each registers and then
+ * check for bits set.
+ */
+static void mhi_ep_check_channel_interrupt(struct mhi_ep_cntrl *mhi_cntrl)
+{
+ u32 ch_int, ch_idx, i;
+
+ /* Bail out if there is no channel doorbell interrupt */
+ if (!mhi_ep_mmio_read_chdb_status_interrupts(mhi_cntrl))
+ return;
+
+ for (i = 0; i < MHI_MASK_ROWS_CH_DB; i++) {
+ ch_idx = i * MHI_MASK_CH_LEN;
+
+ /* Only process channel interrupt if the mask is enabled */
+ ch_int = mhi_cntrl->chdb[i].status & mhi_cntrl->chdb[i].mask;
+ if (ch_int) {
+ mhi_ep_queue_channel_db(mhi_cntrl, ch_int, ch_idx);
+ mhi_ep_mmio_write(mhi_cntrl, MHI_CHDB_INT_CLEAR_n(i),
+ mhi_cntrl->chdb[i].status);
+ }
+ }
+}
+
+static void mhi_ep_process_ctrl_interrupt(struct mhi_ep_cntrl *mhi_cntrl,
+ enum mhi_state state)
+{
+ struct mhi_ep_state_transition *item;
+
+ item = kzalloc(sizeof(*item), GFP_ATOMIC);
+ if (!item)
+ return;
+
+ item->state = state;
+ spin_lock(&mhi_cntrl->list_lock);
+ list_add_tail(&item->node, &mhi_cntrl->st_transition_list);
+ spin_unlock(&mhi_cntrl->list_lock);
+
+ queue_work(mhi_cntrl->wq, &mhi_cntrl->state_work);
+}
+
+/*
+ * Interrupt handler that services interrupts raised by the host writing to
+ * MHICTRL and Command ring doorbell (CRDB) registers for state change and
+ * channel interrupts.
+ */
+static irqreturn_t mhi_ep_irq(int irq, void *data)
+{
+ struct mhi_ep_cntrl *mhi_cntrl = data;
+ struct device *dev = &mhi_cntrl->mhi_dev->dev;
+ enum mhi_state state;
+ u32 int_value;
+
+ /* Acknowledge the ctrl interrupt */
+ int_value = mhi_ep_mmio_read(mhi_cntrl, MHI_CTRL_INT_STATUS);
+ mhi_ep_mmio_write(mhi_cntrl, MHI_CTRL_INT_CLEAR, int_value);
+
+ /* Check for ctrl interrupt */
+ if (FIELD_GET(MHI_CTRL_INT_STATUS_MSK, int_value)) {
+ dev_dbg(dev, "Processing ctrl interrupt\n");
+ mhi_ep_process_ctrl_interrupt(mhi_cntrl, state);
+ }
+
+ /* Check for command doorbell interrupt */
+ if (FIELD_GET(MHI_CTRL_INT_STATUS_CRDB_MSK, int_value))
+ dev_dbg(dev, "Processing command doorbell interrupt\n");
+
+ /* Check for channel interrupts */
+ mhi_ep_check_channel_interrupt(mhi_cntrl);
+
+ return IRQ_HANDLED;
+}
+
static void mhi_ep_release_device(struct device *dev)
{
struct mhi_ep_device *mhi_dev = to_mhi_ep_device(dev);
@@ -338,7 +445,7 @@ int mhi_ep_register_controller(struct mhi_ep_cntrl *mhi_cntrl,
struct mhi_ep_device *mhi_dev;
int ret;
- if (!mhi_cntrl || !mhi_cntrl->cntrl_dev || !mhi_cntrl->mmio)
+ if (!mhi_cntrl || !mhi_cntrl->cntrl_dev || !mhi_cntrl->mmio || !mhi_cntrl->irq)
return -EINVAL;
ret = mhi_ep_chan_init(mhi_cntrl, config);
@@ -360,6 +467,7 @@ int mhi_ep_register_controller(struct mhi_ep_cntrl *mhi_cntrl,
}
INIT_LIST_HEAD(&mhi_cntrl->st_transition_list);
+ INIT_LIST_HEAD(&mhi_cntrl->ch_db_list);
spin_lock_init(&mhi_cntrl->state_lock);
spin_lock_init(&mhi_cntrl->list_lock);
mutex_init(&mhi_cntrl->event_lock);
@@ -375,12 +483,20 @@ int mhi_ep_register_controller(struct mhi_ep_cntrl *mhi_cntrl,
mhi_cntrl->index = ret;
+ irq_set_status_flags(mhi_cntrl->irq, IRQ_NOAUTOEN);
+ ret = request_irq(mhi_cntrl->irq, mhi_ep_irq, IRQF_TRIGGER_HIGH,
+ "doorbell_irq", mhi_cntrl);
+ if (ret) {
+ dev_err(mhi_cntrl->cntrl_dev, "Failed to request Doorbell IRQ\n");
+ goto err_ida_free;
+ }
+
/* Allocate the controller device */
mhi_dev = mhi_ep_alloc_device(mhi_cntrl, MHI_DEVICE_CONTROLLER);
if (IS_ERR(mhi_dev)) {
dev_err(mhi_cntrl->cntrl_dev, "Failed to allocate controller device\n");
ret = PTR_ERR(mhi_dev);
- goto err_ida_free;
+ goto err_free_irq;
}
dev_set_name(&mhi_dev->dev, "mhi_ep%u", mhi_cntrl->index);
@@ -397,6 +513,8 @@ int mhi_ep_register_controller(struct mhi_ep_cntrl *mhi_cntrl,
err_put_dev:
put_device(&mhi_dev->dev);
+err_free_irq:
+ free_irq(mhi_cntrl->irq, mhi_cntrl);
err_ida_free:
ida_free(&mhi_ep_cntrl_ida, mhi_cntrl->index);
err_destroy_wq:
@@ -416,6 +534,8 @@ void mhi_ep_unregister_controller(struct mhi_ep_cntrl *mhi_cntrl)
destroy_workqueue(mhi_cntrl->wq);
+ free_irq(mhi_cntrl->irq, mhi_cntrl);
+
kfree(mhi_cntrl->mhi_cmd);
kfree(mhi_cntrl->mhi_chan);