bus: mhi: core: Add support for data transfer

Add support for transferring data between external modem and host
processor using MHI protocol.

This is based on the patch submitted by Sujeev Dias:
https://lkml.org/lkml/2018/7/9/988

Signed-off-by: Sujeev Dias <sdias@codeaurora.org>
Signed-off-by: Siddartha Mohanadoss <smohanad@codeaurora.org>
[mani: splitted the data transfer patch and cleaned up for upstream]
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Jeffrey Hugo <jhugo@codeaurora.org>
Tested-by: Jeffrey Hugo <jhugo@codeaurora.org>
Link: https://lore.kernel.org/r/20200220095854.4804-12-manivannan.sadhasivam@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/bus/mhi/core/init.c

@@ -491,6 +491,73 @@ int mhi_init_mmio(struct mhi_controller *mhi_cntrl)
 	return 0;
 }
 
+void mhi_deinit_chan_ctxt(struct mhi_controller *mhi_cntrl,
+			  struct mhi_chan *mhi_chan)
+{
+	struct mhi_ring *buf_ring;
+	struct mhi_ring *tre_ring;
+	struct mhi_chan_ctxt *chan_ctxt;
+
+	buf_ring = &mhi_chan->buf_ring;
+	tre_ring = &mhi_chan->tre_ring;
+	chan_ctxt = &mhi_cntrl->mhi_ctxt->chan_ctxt[mhi_chan->chan];
+
+	mhi_free_coherent(mhi_cntrl, tre_ring->alloc_size,
+			  tre_ring->pre_aligned, tre_ring->dma_handle);
+	vfree(buf_ring->base);
+
+	buf_ring->base = tre_ring->base = NULL;
+	chan_ctxt->rbase = 0;
+}
+
+int mhi_init_chan_ctxt(struct mhi_controller *mhi_cntrl,
+		       struct mhi_chan *mhi_chan)
+{
+	struct mhi_ring *buf_ring;
+	struct mhi_ring *tre_ring;
+	struct mhi_chan_ctxt *chan_ctxt;
+	u32 tmp;
+	int ret;
+
+	buf_ring = &mhi_chan->buf_ring;
+	tre_ring = &mhi_chan->tre_ring;
+	tre_ring->el_size = sizeof(struct mhi_tre);
+	tre_ring->len = tre_ring->el_size * tre_ring->elements;
+	chan_ctxt = &mhi_cntrl->mhi_ctxt->chan_ctxt[mhi_chan->chan];
+	ret = mhi_alloc_aligned_ring(mhi_cntrl, tre_ring, tre_ring->len);
+	if (ret)
+		return -ENOMEM;
+
+	buf_ring->el_size = sizeof(struct mhi_buf_info);
+	buf_ring->len = buf_ring->el_size * buf_ring->elements;
+	buf_ring->base = vzalloc(buf_ring->len);
+
+	if (!buf_ring->base) {
+		mhi_free_coherent(mhi_cntrl, tre_ring->alloc_size,
+				  tre_ring->pre_aligned, tre_ring->dma_handle);
+		return -ENOMEM;
+	}
+
+	tmp = chan_ctxt->chcfg;
+	tmp &= ~CHAN_CTX_CHSTATE_MASK;
+	tmp |= (MHI_CH_STATE_ENABLED << CHAN_CTX_CHSTATE_SHIFT);
+	chan_ctxt->chcfg = tmp;
+
+	chan_ctxt->rbase = tre_ring->iommu_base;
+	chan_ctxt->rp = chan_ctxt->wp = chan_ctxt->rbase;
+	chan_ctxt->rlen = tre_ring->len;
+	tre_ring->ctxt_wp = &chan_ctxt->wp;
+
+	tre_ring->rp = tre_ring->wp = tre_ring->base;
+	buf_ring->rp = buf_ring->wp = buf_ring->base;
+	mhi_chan->db_cfg.db_mode = 1;
+
+	/* Update to all cores */
+	smp_wmb();
+
+	return 0;
+}
+
 static int parse_ev_cfg(struct mhi_controller *mhi_cntrl,
 			struct mhi_controller_config *config)
 {
@@ -799,6 +866,14 @@ int mhi_register_controller(struct mhi_controller *mhi_cntrl,
 		rwlock_init(&mhi_chan->lock);
 	}
 
+	if (mhi_cntrl->bounce_buf) {
+		mhi_cntrl->map_single = mhi_map_single_use_bb;
+		mhi_cntrl->unmap_single = mhi_unmap_single_use_bb;
+	} else {
+		mhi_cntrl->map_single = mhi_map_single_no_bb;
+		mhi_cntrl->unmap_single = mhi_unmap_single_no_bb;
+	}
+
 	/* Register controller with MHI bus */
 	mhi_dev = mhi_alloc_device(mhi_cntrl);
 	if (IS_ERR(mhi_dev)) {
@@ -969,6 +1044,14 @@ static int mhi_driver_probe(struct device *dev)
 	struct mhi_event *mhi_event;
 	struct mhi_chan *ul_chan = mhi_dev->ul_chan;
 	struct mhi_chan *dl_chan = mhi_dev->dl_chan;
+	int ret;
+
+	/* Bring device out of LPM */
+	ret = mhi_device_get_sync(mhi_dev);
+	if (ret)
+		return ret;
+
+	ret = -EINVAL;
 
 	if (ul_chan) {
 		/*
@@ -976,13 +1059,18 @@ static int mhi_driver_probe(struct device *dev)
 		 * be provided
 		 */
 		if (ul_chan->lpm_notify && !mhi_drv->status_cb)
-			return -EINVAL;
+			goto exit_probe;
 
 		/* For non-offload channels then xfer_cb should be provided */
 		if (!ul_chan->offload_ch && !mhi_drv->ul_xfer_cb)
-			return -EINVAL;
+			goto exit_probe;
 
 		ul_chan->xfer_cb = mhi_drv->ul_xfer_cb;
+		if (ul_chan->auto_start) {
+			ret = mhi_prepare_channel(mhi_cntrl, ul_chan);
+			if (ret)
+				goto exit_probe;
+		}
 	}
 
 	if (dl_chan) {
@@ -991,11 +1079,11 @@ static int mhi_driver_probe(struct device *dev)
 		 * be provided
 		 */
 		if (dl_chan->lpm_notify && !mhi_drv->status_cb)
-			return -EINVAL;
+			goto exit_probe;
 
 		/* For non-offload channels then xfer_cb should be provided */
 		if (!dl_chan->offload_ch && !mhi_drv->dl_xfer_cb)
-			return -EINVAL;
+			goto exit_probe;
 
 		mhi_event = &mhi_cntrl->mhi_event[dl_chan->er_index];
 
@@ -1005,19 +1093,36 @@ static int mhi_driver_probe(struct device *dev)
 		 * notify pending data
 		 */
 		if (mhi_event->cl_manage && !mhi_drv->status_cb)
-			return -EINVAL;
+			goto exit_probe;
 
 		dl_chan->xfer_cb = mhi_drv->dl_xfer_cb;
 	}
 
 	/* Call the user provided probe function */
-	return mhi_drv->probe(mhi_dev, mhi_dev->id);
+	ret = mhi_drv->probe(mhi_dev, mhi_dev->id);
+	if (ret)
+		goto exit_probe;
+
+	if (dl_chan && dl_chan->auto_start)
+		mhi_prepare_channel(mhi_cntrl, dl_chan);
+
+	mhi_device_put(mhi_dev);
+
+	return ret;
+
+exit_probe:
+	mhi_unprepare_from_transfer(mhi_dev);
+
+	mhi_device_put(mhi_dev);
+
+	return ret;
 }
 
 static int mhi_driver_remove(struct device *dev)
 {
 	struct mhi_device *mhi_dev = to_mhi_device(dev);
 	struct mhi_driver *mhi_drv = to_mhi_driver(dev->driver);
+	struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
 	struct mhi_chan *mhi_chan;
 	enum mhi_ch_state ch_state[] = {
 		MHI_CH_STATE_DISABLED,
@@ -1049,6 +1154,10 @@ static int mhi_driver_remove(struct device *dev)
 		mhi_chan->ch_state = MHI_CH_STATE_SUSPENDED;
 		write_unlock_irq(&mhi_chan->lock);
 
+		/* Reset the non-offload channel */
+		if (!mhi_chan->offload_ch)
+			mhi_reset_chan(mhi_cntrl, mhi_chan);
+
 		mutex_unlock(&mhi_chan->mutex);
 	}
 
@@ -1063,11 +1172,20 @@ static int mhi_driver_remove(struct device *dev)
 
 		mutex_lock(&mhi_chan->mutex);
 
+		if (ch_state[dir] == MHI_CH_STATE_ENABLED &&
+		    !mhi_chan->offload_ch)
+			mhi_deinit_chan_ctxt(mhi_cntrl, mhi_chan);
+
 		mhi_chan->ch_state = MHI_CH_STATE_DISABLED;
 
 		mutex_unlock(&mhi_chan->mutex);
 	}
 
+	read_lock_bh(&mhi_cntrl->pm_lock);
+	while (mhi_dev->dev_wake)
+		mhi_device_put(mhi_dev);
+	read_unlock_bh(&mhi_cntrl->pm_lock);
+
 	return 0;
 }
 

drivers/bus/mhi/core/internal.h

@@ -587,6 +587,8 @@ int mhi_pm_m0_transition(struct mhi_controller *mhi_cntrl);
 void mhi_pm_m1_transition(struct mhi_controller *mhi_cntrl);
 int mhi_pm_m3_transition(struct mhi_controller *mhi_cntrl);
 int __mhi_device_get_sync(struct mhi_controller *mhi_cntrl);
+int mhi_send_cmd(struct mhi_controller *mhi_cntrl, struct mhi_chan *mhi_chan,
+		 enum mhi_cmd_type cmd);
 
 /* Register access methods */
 void mhi_db_brstmode(struct mhi_controller *mhi_cntrl, struct db_cfg *db_cfg,
@@ -618,6 +620,14 @@ int mhi_init_irq_setup(struct mhi_controller *mhi_cntrl);
 void mhi_deinit_free_irq(struct mhi_controller *mhi_cntrl);
 void mhi_rddm_prepare(struct mhi_controller *mhi_cntrl,
 		      struct image_info *img_info);
+int mhi_prepare_channel(struct mhi_controller *mhi_cntrl,
+			struct mhi_chan *mhi_chan);
+int mhi_init_chan_ctxt(struct mhi_controller *mhi_cntrl,
+		       struct mhi_chan *mhi_chan);
+void mhi_deinit_chan_ctxt(struct mhi_controller *mhi_cntrl,
+			  struct mhi_chan *mhi_chan);
+void mhi_reset_chan(struct mhi_controller *mhi_cntrl,
+		    struct mhi_chan *mhi_chan);
 
 /* Memory allocation methods */
 static inline void *mhi_alloc_coherent(struct mhi_controller *mhi_cntrl,
@@ -652,4 +662,16 @@ irqreturn_t mhi_irq_handler(int irq_number, void *dev);
 irqreturn_t mhi_intvec_threaded_handler(int irq_number, void *dev);
 irqreturn_t mhi_intvec_handler(int irq_number, void *dev);
 
+int mhi_gen_tre(struct mhi_controller *mhi_cntrl, struct mhi_chan *mhi_chan,
+		void *buf, void *cb, size_t buf_len, enum mhi_flags flags);
+
+int mhi_map_single_no_bb(struct mhi_controller *mhi_cntrl,
+			 struct mhi_buf_info *buf_info);
+int mhi_map_single_use_bb(struct mhi_controller *mhi_cntrl,
+			  struct mhi_buf_info *buf_info);
+void mhi_unmap_single_no_bb(struct mhi_controller *mhi_cntrl,
+			    struct mhi_buf_info *buf_info);
+void mhi_unmap_single_use_bb(struct mhi_controller *mhi_cntrl,
+			     struct mhi_buf_info *buf_info);
+
 #endif /* _MHI_INT_H */

drivers/bus/mhi/core/pm.c

@@ -927,3 +927,43 @@ int mhi_force_rddm_mode(struct mhi_controller *mhi_cntrl)
 	return ret;
 }
 EXPORT_SYMBOL_GPL(mhi_force_rddm_mode);
+
+void mhi_device_get(struct mhi_device *mhi_dev)
+{
+	struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
+
+	mhi_dev->dev_wake++;
+	read_lock_bh(&mhi_cntrl->pm_lock);
+	mhi_cntrl->wake_get(mhi_cntrl, true);
+	read_unlock_bh(&mhi_cntrl->pm_lock);
+}
+EXPORT_SYMBOL_GPL(mhi_device_get);
+
+int mhi_device_get_sync(struct mhi_device *mhi_dev)
+{
+	struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
+	int ret;
+
+	ret = __mhi_device_get_sync(mhi_cntrl);
+	if (!ret)
+		mhi_dev->dev_wake++;
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(mhi_device_get_sync);
+
+void mhi_device_put(struct mhi_device *mhi_dev)
+{
+	struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
+
+	mhi_dev->dev_wake--;
+	read_lock_bh(&mhi_cntrl->pm_lock);
+	if (MHI_PM_IN_SUSPEND_STATE(mhi_cntrl->pm_state)) {
+		mhi_cntrl->runtime_get(mhi_cntrl);
+		mhi_cntrl->runtime_put(mhi_cntrl);
+	}
+
+	mhi_cntrl->wake_put(mhi_cntrl, false);
+	read_unlock_bh(&mhi_cntrl->pm_lock);
+}
+EXPORT_SYMBOL_GPL(mhi_device_put);

include/linux/mhi.h

@@ -10,6 +10,7 @@
 #include <linux/dma-direction.h>
 #include <linux/mutex.h>
 #include <linux/rwlock_types.h>
+#include <linux/skbuff.h>
 #include <linux/slab.h>
 #include <linux/spinlock_types.h>
 #include <linux/wait.h>
@@ -336,6 +337,8 @@ struct mhi_controller_config {
  * @wake_toggle: CB function to assert and de-assert device wake (optional)
  * @runtime_get: CB function to controller runtime resume (required)
  * @runtimet_put: CB function to decrement pm usage (required)
+ * @map_single: CB function to create TRE buffer
+ * @unmap_single: CB function to destroy TRE buffer
  * @buffer_len: Bounce buffer length
  * @bounce_buf: Use of bounce buffer
  * @fbc_download: MHI host needs to do complete image transfer (optional)
@@ -403,6 +406,10 @@ struct mhi_controller {
 	void (*wake_toggle)(struct mhi_controller *mhi_cntrl);
 	int (*runtime_get)(struct mhi_controller *mhi_cntrl);
 	void (*runtime_put)(struct mhi_controller *mhi_cntrl);
+	int (*map_single)(struct mhi_controller *mhi_cntrl,
+			  struct mhi_buf_info *buf);
+	void (*unmap_single)(struct mhi_controller *mhi_cntrl,
+			     struct mhi_buf_info *buf);
 
 	size_t buffer_len;
 	bool bounce_buf;
@@ -583,4 +590,77 @@ int mhi_force_rddm_mode(struct mhi_controller *mhi_cntrl);
  */
 enum mhi_state mhi_get_mhi_state(struct mhi_controller *mhi_cntrl);
 
+/**
+ * mhi_device_get - Disable device low power mode
+ * @mhi_dev: Device associated with the channel
+ */
+void mhi_device_get(struct mhi_device *mhi_dev);
+
+/**
+ * mhi_device_get_sync - Disable device low power mode. Synchronously
+ *                       take the controller out of suspended state
+ * @mhi_dev: Device associated with the channel
+ */
+int mhi_device_get_sync(struct mhi_device *mhi_dev);
+
+/**
+ * mhi_device_put - Re-enable device low power mode
+ * @mhi_dev: Device associated with the channel
+ */
+void mhi_device_put(struct mhi_device *mhi_dev);
+
+/**
+ * mhi_prepare_for_transfer - Setup channel for data transfer
+ * @mhi_dev: Device associated with the channels
+ */
+int mhi_prepare_for_transfer(struct mhi_device *mhi_dev);
+
+/**
+ * mhi_unprepare_from_transfer - Unprepare the channels
+ * @mhi_dev: Device associated with the channels
+ */
+void mhi_unprepare_from_transfer(struct mhi_device *mhi_dev);
+
+/**
+ * mhi_poll - Poll for any available data in DL direction
+ * @mhi_dev: Device associated with the channels
+ * @budget: # of events to process
+ */
+int mhi_poll(struct mhi_device *mhi_dev, u32 budget);
+
+/**
+ * mhi_queue_dma - Send or receive DMA mapped buffers from client device
+ *                 over MHI channel
+ * @mhi_dev: Device associated with the channels
+ * @dir: DMA direction for the channel
+ * @mhi_buf: Buffer for holding the DMA mapped data
+ * @len: Buffer length
+ * @mflags: MHI transfer flags used for the transfer
+ */
+int mhi_queue_dma(struct mhi_device *mhi_dev, enum dma_data_direction dir,
+		  struct mhi_buf *mhi_buf, size_t len, enum mhi_flags mflags);
+
+/**
+ * mhi_queue_buf - Send or receive raw buffers from client device over MHI
+ *                 channel
+ * @mhi_dev: Device associated with the channels
+ * @dir: DMA direction for the channel
+ * @buf: Buffer for holding the data
+ * @len: Buffer length
+ * @mflags: MHI transfer flags used for the transfer
+ */
+int mhi_queue_buf(struct mhi_device *mhi_dev, enum dma_data_direction dir,
+		  void *buf, size_t len, enum mhi_flags mflags);
+
+/**
+ * mhi_queue_skb - Send or receive SKBs from client device over MHI channel
+ * @mhi_dev: Device associated with the channels
+ * @dir: DMA direction for the channel
+ * @skb: Buffer for holding SKBs
+ * @len: Buffer length
+ * @mflags: MHI transfer flags used for the transfer
+ */
+int mhi_queue_skb(struct mhi_device *mhi_dev, enum dma_data_direction dir,
+		  struct sk_buff *skb, size_t len, enum mhi_flags mflags);
+
 #endif /* _MHI_H_ */