serial: 8250_mid: add support for DMA engine handling from UART MMIO

The platforms that have this UART, but that don't have
separate PCI device for the DMA Engine, need to create the
HSU DMA Engine device separately.
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_mid.c

@@ -21,6 +21,7 @@
 #define PCI_DEVICE_ID_INTEL_PNW_UART2	0x081c
 #define PCI_DEVICE_ID_INTEL_PNW_UART3	0x081d
 #define PCI_DEVICE_ID_INTEL_TNG_UART	0x1191
+#define PCI_DEVICE_ID_INTEL_DNV_UART	0x19d8
 
 /* Intel MID Specific registers */
 #define INTEL_MID_UART_PS		0x30
@@ -33,6 +34,7 @@ struct mid8250_board {
 	unsigned long freq;
 	unsigned int base_baud;
 	int (*setup)(struct mid8250 *, struct uart_port *p);
+	void (*exit)(struct mid8250 *);
 };
 
 struct mid8250 {
@@ -41,6 +43,7 @@ struct mid8250 {
 	struct pci_dev *dma_dev;
 	struct uart_8250_dma dma;
 	struct mid8250_board *board;
+	struct hsu_dma_chip dma_chip;
 };
 
 /*****************************************************************************/
@@ -82,6 +85,53 @@ static int tng_setup(struct mid8250 *mid, struct uart_port *p)
 	return 0;
 }
 
+static int dnv_handle_irq(struct uart_port *p)
+{
+	struct mid8250 *mid = p->private_data;
+	int ret;
+
+	ret = hsu_dma_irq(&mid->dma_chip, 0);
+	ret |= hsu_dma_irq(&mid->dma_chip, 1);
+
+	/* For now, letting the HW generate separate interrupt for the UART */
+	if (ret)
+		return ret;
+
+	return serial8250_handle_irq(p, serial_port_in(p, UART_IIR));
+}
+
+#define DNV_DMA_CHAN_OFFSET 0x80
+
+static int dnv_setup(struct mid8250 *mid, struct uart_port *p)
+{
+	struct hsu_dma_chip *chip = &mid->dma_chip;
+	struct pci_dev *pdev = to_pci_dev(p->dev);
+	int ret;
+
+	chip->dev = &pdev->dev;
+	chip->irq = pdev->irq;
+	chip->regs = p->membase;
+	chip->length = pci_resource_len(pdev, 0);
+	chip->offset = DNV_DMA_CHAN_OFFSET;
+
+	/* Falling back to PIO mode if DMA probing fails */
+	ret = hsu_dma_probe(chip);
+	if (ret)
+		return 0;
+
+	mid->dma_dev = pdev;
+
+	p->handle_irq = dnv_handle_irq;
+	return 0;
+}
+
+static void dnv_exit(struct mid8250 *mid)
+{
+	if (!mid->dma_dev)
+		return;
+	hsu_dma_remove(&mid->dma_chip);
+}
+
 /*****************************************************************************/
 
 static void mid8250_set_termios(struct uart_port *p,
@@ -135,6 +185,9 @@ static int mid8250_dma_setup(struct mid8250 *mid, struct uart_8250_port *port)
 	struct hsu_dma_slave *rx_param;
 	struct hsu_dma_slave *tx_param;
 
+	if (!mid->dma_dev)
+		return 0;
+
 	rx_param = devm_kzalloc(dev, sizeof(*rx_param), GFP_KERNEL);
 	if (!rx_param)
 		return -ENOMEM;
@@ -202,22 +255,29 @@ static int mid8250_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 
 	ret = mid8250_dma_setup(mid, &uart);
 	if (ret)
-		return ret;
+		goto err;
 
 	ret = serial8250_register_8250_port(&uart);
 	if (ret < 0)
-		return ret;
+		goto err;
 
 	mid->line = ret;
 
 	pci_set_drvdata(pdev, mid);
 	return 0;
+err:
+	if (mid->board->exit)
+		mid->board->exit(mid);
+	return ret;
 }
 
 static void mid8250_remove(struct pci_dev *pdev)
 {
 	struct mid8250 *mid = pci_get_drvdata(pdev);
 
+	if (mid->board->exit)
+		mid->board->exit(mid);
+
 	serial8250_unregister_port(mid->line);
 }
 
@@ -233,6 +293,13 @@ static const struct mid8250_board tng_board = {
 	.setup = tng_setup,
 };
 
+static const struct mid8250_board dnv_board = {
+	.freq = 133333333,
+	.base_baud = 115200,
+	.setup = dnv_setup,
+	.exit = dnv_exit,
+};
+
 #define MID_DEVICE(id, board) { PCI_VDEVICE(INTEL, id), (kernel_ulong_t)&board }
 
 static const struct pci_device_id pci_ids[] = {
@@ -240,6 +307,7 @@ static const struct pci_device_id pci_ids[] = {
 	MID_DEVICE(PCI_DEVICE_ID_INTEL_PNW_UART2, pnw_board),
 	MID_DEVICE(PCI_DEVICE_ID_INTEL_PNW_UART3, pnw_board),
 	MID_DEVICE(PCI_DEVICE_ID_INTEL_TNG_UART, tng_board),
+	MID_DEVICE(PCI_DEVICE_ID_INTEL_DNV_UART, dnv_board),
 	{ },
 };
 MODULE_DEVICE_TABLE(pci, pci_ids);

drivers/tty/serial/8250/8250_pci.c

@@ -3809,6 +3809,7 @@ static const struct pci_device_id blacklist[] = {
 	{ PCI_VDEVICE(INTEL, 0x081c), },
 	{ PCI_VDEVICE(INTEL, 0x081d), },
 	{ PCI_VDEVICE(INTEL, 0x1191), },
+	{ PCI_VDEVICE(INTEL, 0x19d8), },
 };
 
 /*