usb: renesas_usbhs: add support for USB-DMAC

Some Renesas SoCs have the USB-DMAC. It is able to terminate transfers
when a short packet is received, even if less bytes than the transfer
counter size have been received. Also, it is able to send a short
packet even if the packet size is not multiples of 8bytes.

Since the previous code has used the interruption of USBHS controller
when receiving packets even if this driver has used a dmac, a lot of
interruptions has happened. This patch will reduce such interruptions.

This patch allows to use the USB-DMAC on R-Car H2 and M2.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

1 files changed, 159 insertions, 6 deletions

diff --git a/drivers/usb/renesas_usbhs/fifo.c b/drivers/usb/renesas_usbhs/fifo.c
index b737661b10a2..8597cf9cfceb 100644
--- a/drivers/usb/renesas_usbhs/fifo.c
+++ b/drivers/usb/renesas_usbhs/fifo.c
@@ -813,7 +813,8 @@ static void xfer_work(struct work_struct *work)
 	desc->callback		= usbhsf_dma_complete;
 	desc->callback_param	= pipe;
 
-	if (dmaengine_submit(desc) < 0) {
+	pkt->cookie = dmaengine_submit(desc);
+	if (pkt->cookie < 0) {
 		dev_err(dev, "Failed to submit dma descriptor\n");
 		return;
 	}
@@ -838,6 +839,7 @@ static int usbhsf_dma_prepare_push(struct usbhs_pkt *pkt, int *is_done)
 	struct usbhs_fifo *fifo;
 	int len = pkt->length - pkt->actual;
 	int ret;
+	uintptr_t align_mask;
 
 	if (usbhs_pipe_is_busy(pipe))
 		return 0;
@@ -847,10 +849,14 @@ static int usbhsf_dma_prepare_push(struct usbhs_pkt *pkt, int *is_done)
 	    usbhs_pipe_is_dcp(pipe))
 		goto usbhsf_pio_prepare_push;
 
-	if (len & 0x7) /* 8byte alignment */
+	/* check data length if this driver don't use USB-DMAC */
+	if (!usbhs_get_dparam(priv, has_usb_dmac) && len & 0x7)
 		goto usbhsf_pio_prepare_push;
 
-	if ((uintptr_t)(pkt->buf + pkt->actual) & 0x7) /* 8byte alignment */
+	/* check buffer alignment */
+	align_mask = usbhs_get_dparam(priv, has_usb_dmac) ?
+					USBHS_USB_DMAC_XFER_SIZE - 1 : 0x7;
+	if ((uintptr_t)(pkt->buf + pkt->actual) & align_mask)
 		goto usbhsf_pio_prepare_push;
 
 	/* return at this time if the pipe is running */
@@ -924,7 +930,85 @@ struct usbhs_pkt_handle usbhs_fifo_dma_push_handler = {
 /*
  *		DMA pop handler
  */
-static int usbhsf_dma_try_pop(struct usbhs_pkt *pkt, int *is_done)
+
+static int usbhsf_dma_prepare_pop_with_rx_irq(struct usbhs_pkt *pkt,
+					      int *is_done)
+{
+	return usbhsf_prepare_pop(pkt, is_done);
+}
+
+static int usbhsf_dma_prepare_pop_with_usb_dmac(struct usbhs_pkt *pkt,
+						int *is_done)
+{
+	struct usbhs_pipe *pipe = pkt->pipe;
+	struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);
+	struct usbhs_fifo *fifo;
+	int ret;
+
+	if (usbhs_pipe_is_busy(pipe))
+		return 0;
+
+	/* use PIO if packet is less than pio_dma_border or pipe is DCP */
+	if ((pkt->length < usbhs_get_dparam(priv, pio_dma_border)) ||
+	    usbhs_pipe_is_dcp(pipe))
+		goto usbhsf_pio_prepare_pop;
+
+	fifo = usbhsf_get_dma_fifo(priv, pkt);
+	if (!fifo)
+		goto usbhsf_pio_prepare_pop;
+
+	if ((uintptr_t)pkt->buf & (USBHS_USB_DMAC_XFER_SIZE - 1))
+		goto usbhsf_pio_prepare_pop;
+
+	usbhs_pipe_config_change_bfre(pipe, 1);
+
+	ret = usbhsf_fifo_select(pipe, fifo, 0);
+	if (ret < 0)
+		goto usbhsf_pio_prepare_pop;
+
+	if (usbhsf_dma_map(pkt) < 0)
+		goto usbhsf_pio_prepare_pop_unselect;
+
+	/* DMA */
+
+	/*
+	 * usbhs_fifo_dma_pop_handler :: prepare
+	 * enabled irq to come here.
+	 * but it is no longer needed for DMA. disable it.
+	 */
+	usbhsf_rx_irq_ctrl(pipe, 0);
+
+	pkt->trans = pkt->length;
+
+	INIT_WORK(&pkt->work, xfer_work);
+	schedule_work(&pkt->work);
+
+	return 0;
+
+usbhsf_pio_prepare_pop_unselect:
+	usbhsf_fifo_unselect(pipe, fifo);
+usbhsf_pio_prepare_pop:
+
+	/*
+	 * change handler to PIO
+	 */
+	pkt->handler = &usbhs_fifo_pio_pop_handler;
+	usbhs_pipe_config_change_bfre(pipe, 0);
+
+	return pkt->handler->prepare(pkt, is_done);
+}
+
+static int usbhsf_dma_prepare_pop(struct usbhs_pkt *pkt, int *is_done)
+{
+	struct usbhs_priv *priv = usbhs_pipe_to_priv(pkt->pipe);
+
+	if (usbhs_get_dparam(priv, has_usb_dmac))
+		return usbhsf_dma_prepare_pop_with_usb_dmac(pkt, is_done);
+	else
+		return usbhsf_dma_prepare_pop_with_rx_irq(pkt, is_done);
+}
+
+static int usbhsf_dma_try_pop_with_rx_irq(struct usbhs_pkt *pkt, int *is_done)
 {
 	struct usbhs_pipe *pipe = pkt->pipe;
 	struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);
@@ -993,7 +1077,16 @@ usbhsf_pio_prepare_pop:
 	return pkt->handler->try_run(pkt, is_done);
 }
 
-static int usbhsf_dma_pop_done(struct usbhs_pkt *pkt, int *is_done)
+static int usbhsf_dma_try_pop(struct usbhs_pkt *pkt, int *is_done)
+{
+	struct usbhs_priv *priv = usbhs_pipe_to_priv(pkt->pipe);
+
+	BUG_ON(usbhs_get_dparam(priv, has_usb_dmac));
+
+	return usbhsf_dma_try_pop_with_rx_irq(pkt, is_done);
+}
+
+static int usbhsf_dma_pop_done_with_rx_irq(struct usbhs_pkt *pkt, int *is_done)
 {
 	struct usbhs_pipe *pipe = pkt->pipe;
 	int maxp = usbhs_pipe_get_maxpacket(pipe);
@@ -1017,8 +1110,68 @@ static int usbhsf_dma_pop_done(struct usbhs_pkt *pkt, int *is_done)
 	return 0;
 }
 
+static size_t usbhs_dma_calc_received_size(struct usbhs_pkt *pkt,
+					   struct dma_chan *chan, int dtln)
+{
+	struct usbhs_pipe *pipe = pkt->pipe;
+	struct dma_tx_state state;
+	size_t received_size;
+	int maxp = usbhs_pipe_get_maxpacket(pipe);
+
+	dmaengine_tx_status(chan, pkt->cookie, &state);
+	received_size = pkt->length - state.residue;
+
+	if (dtln) {
+		received_size -= USBHS_USB_DMAC_XFER_SIZE;
+		received_size &= ~(maxp - 1);
+		received_size += dtln;
+	}
+
+	return received_size;
+}
+
+static int usbhsf_dma_pop_done_with_usb_dmac(struct usbhs_pkt *pkt,
+					     int *is_done)
+{
+	struct usbhs_pipe *pipe = pkt->pipe;
+	struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);
+	struct usbhs_fifo *fifo = usbhs_pipe_to_fifo(pipe);
+	struct dma_chan *chan = usbhsf_dma_chan_get(fifo, pkt);
+	int rcv_len;
+
+	/*
+	 * Since the driver disables rx_irq in DMA mode, the interrupt handler
+	 * cannot the BRDYSTS. So, the function clears it here because the
+	 * driver may use PIO mode next time.
+	 */
+	usbhs_xxxsts_clear(priv, BRDYSTS, usbhs_pipe_number(pipe));
+
+	rcv_len = usbhsf_fifo_rcv_len(priv, fifo);
+	usbhsf_fifo_clear(pipe, fifo);
+	pkt->actual = usbhs_dma_calc_received_size(pkt, chan, rcv_len);
+
+	usbhsf_dma_stop(pipe, fifo);
+	usbhsf_dma_unmap(pkt);
+	usbhsf_fifo_unselect(pipe, pipe->fifo);
+
+	/* The driver can assume the rx transaction is always "done" */
+	*is_done = 1;
+
+	return 0;
+}
+
+static int usbhsf_dma_pop_done(struct usbhs_pkt *pkt, int *is_done)
+{
+	struct usbhs_priv *priv = usbhs_pipe_to_priv(pkt->pipe);
+
+	if (usbhs_get_dparam(priv, has_usb_dmac))
+		return usbhsf_dma_pop_done_with_usb_dmac(pkt, is_done);
+	else
+		return usbhsf_dma_pop_done_with_rx_irq(pkt, is_done);
+}
+
 struct usbhs_pkt_handle usbhs_fifo_dma_pop_handler = {
-	.prepare	= usbhsf_prepare_pop,
+	.prepare	= usbhsf_dma_prepare_pop,
 	.try_run	= usbhsf_dma_try_pop,
 	.dma_done	= usbhsf_dma_pop_done
 };