usb: musb: jz4740: Add support for DMA

Add support for using the DMA channels built into the Inventra IP.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Tested-by: Artur Rojek <contact@artur-rojek.eu>
Signed-off-by: Bin Liu <b-liu@ti.com>
Link: https://lore.kernel.org/r/20200316211136.2274-4-b-liu@ti.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/musb/Kconfig

@@ -144,7 +144,7 @@ config USB_UX500_DMA
 
 config USB_INVENTRA_DMA
 	bool 'Inventra'
-	depends on USB_MUSB_OMAP2PLUS || USB_MUSB_MEDIATEK
+	depends on USB_MUSB_OMAP2PLUS || USB_MUSB_MEDIATEK || USB_MUSB_JZ4740
 	help
 	  Enable DMA transfers using Mentor's engine.
 

drivers/usb/musb/jz4740.c

@@ -24,11 +24,14 @@ struct jz4740_glue {
 static irqreturn_t jz4740_musb_interrupt(int irq, void *__hci)
 {
 	unsigned long	flags;
-	irqreturn_t	retval = IRQ_NONE;
+	irqreturn_t	retval = IRQ_NONE, retval_dma = IRQ_NONE;
 	struct musb	*musb = __hci;
 
 	spin_lock_irqsave(&musb->lock, flags);
 
+	if (IS_ENABLED(CONFIG_USB_INVENTRA_DMA) && musb->dma_controller)
+		retval_dma = dma_controller_irq(irq, musb->dma_controller);
+
 	musb->int_usb = musb_readb(musb->mregs, MUSB_INTRUSB);
 	musb->int_tx = musb_readw(musb->mregs, MUSB_INTRTX);
 	musb->int_rx = musb_readw(musb->mregs, MUSB_INTRRX);
@@ -46,7 +49,10 @@ static irqreturn_t jz4740_musb_interrupt(int irq, void *__hci)
 
 	spin_unlock_irqrestore(&musb->lock, flags);
 
-	return retval;
+	if (retval == IRQ_HANDLED || retval_dma == IRQ_HANDLED)
+		return IRQ_HANDLED;
+
+	return IRQ_NONE;
 }
 
 static struct musb_fifo_cfg jz4740_musb_fifo_cfg[] = {
@@ -93,14 +99,14 @@ static int jz4740_musb_init(struct musb *musb)
 	return 0;
 }
 
-/*
- * DMA has not been confirmed to work with CONFIG_USB_INVENTRA_DMA,
- * so let's not set up the dma function pointers yet.
- */
 static const struct musb_platform_ops jz4740_musb_ops = {
 	.quirks		= MUSB_DMA_INVENTRA | MUSB_INDEXED_EP,
 	.fifo_mode	= 2,
 	.init		= jz4740_musb_init,
+#ifdef CONFIG_USB_INVENTRA_DMA
+	.dma_init	= musbhs_dma_controller_create_noirq,
+	.dma_exit	= musbhs_dma_controller_destroy,
+#endif
 };
 
 static const struct musb_hdrc_platform_data jz4740_musb_pdata = {
@@ -142,6 +148,8 @@ static int jz4740_probe(struct platform_device *pdev)
 	}
 
 	musb->dev.parent		= dev;
+	musb->dev.dma_mask		= &musb->dev.coherent_dma_mask;
+	musb->dev.coherent_dma_mask	= DMA_BIT_MASK(32);
 
 	glue->pdev			= musb;
 	glue->clk			= clk;