serial: 8250_ingenic: Enable FIFO for Ingenic UARTs

Enable the TX/RX FIFOs present on UARTs in Ingenic SoCs.
FIFO sizes vary per device so match these based on
the OF compatible string

Enabling the FIFOs permits much faster transfer with
lower CPU overhead.

Tested on Ingenic JZ4780 on the MIPS Ci20 Creator board

Signed-off-by: Matt Redfearn <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/tty/serial/8250/8250_ingenic.c

···
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_fdt.h>
+#include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/serial_8250.h>
 #include <linux/serial_core.h>
 #include <linux/serial_reg.h>
+
+#include "8250.h"
+
+/** ingenic_uart_config: SOC specific config data. */
+struct ingenic_uart_config {
+	int tx_loadsz;
+	int fifosize;
+};
 
 struct ingenic_uart_data {
 	struct clk	*clk_module;
 	struct clk	*clk_baud;
 	int		line;
 };
+
+static const struct of_device_id of_match[];
 
 #define UART_FCR_UME	BIT(4)
 
···
 	struct resource *regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	struct resource *irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 	struct ingenic_uart_data *data;
+	const struct ingenic_uart_config *cdata;
+	const struct of_device_id *match;
 	int err, line;
+
+	match = of_match_device(of_match, &pdev->dev);
+	if (!match) {
+		dev_err(&pdev->dev, "Error: No device match found\n");
+		return -ENODEV;
+	}
+	cdata = match->data;
 
 	if (!regs || !irq) {
 		dev_err(&pdev->dev, "no registers/irq defined\n");
···
 		return -ENOMEM;
 
 	spin_lock_init(&uart.port.lock);
-	uart.port.type = PORT_16550;
+	uart.port.type = PORT_16550A;
 	uart.port.flags = UPF_SKIP_TEST | UPF_IOREMAP | UPF_FIXED_TYPE;
 	uart.port.iotype = UPIO_MEM;
 	uart.port.mapbase = regs->start;
···
 	uart.port.serial_in = ingenic_uart_serial_in;
 	uart.port.irq = irq->start;
 	uart.port.dev = &pdev->dev;
+	uart.port.fifosize = cdata->fifosize;
+	uart.tx_loadsz = cdata->tx_loadsz;
+	uart.capabilities = UART_CAP_FIFO | UART_CAP_RTOIE;
 
 	/* Check for a fixed line number */
 	line = of_alias_get_id(pdev->dev.of_node, "serial");
···
 	return 0;
 }
 
+static const struct ingenic_uart_config jz4740_uart_config = {
+	.tx_loadsz = 8,
+	.fifosize = 16,
+};
+
+static const struct ingenic_uart_config jz4760_uart_config = {
+	.tx_loadsz = 16,
+	.fifosize = 32,
+};
+
+static const struct ingenic_uart_config jz4780_uart_config = {
+	.tx_loadsz = 32,
+	.fifosize = 64,
+};
+
 static const struct of_device_id of_match[] = {
-	{ .compatible = "ingenic,jz4740-uart" },
-	{ .compatible = "ingenic,jz4775-uart" },
-	{ .compatible = "ingenic,jz4780-uart" },
+	{ .compatible = "ingenic,jz4740-uart", .data = &jz4740_uart_config },
+	{ .compatible = "ingenic,jz4760-uart", .data = &jz4760_uart_config },
+	{ .compatible = "ingenic,jz4775-uart", .data = &jz4760_uart_config },
+	{ .compatible = "ingenic,jz4780-uart", .data = &jz4780_uart_config },
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, of_match);