--- /dev/null
+/*
+ * xen/drivers/char/mvebu3700-uart.c
+ *
+ * Driver for Marvell MVEBU UART.
+ *
+ * Copyright (c) 2018, Amit Singh Tomar <amittomer25@gmail.com>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms and conditions of the GNU General Public
+ * License, version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <xen/irq.h>
+#include <xen/serial.h>
+#include <xen/vmap.h>
+#include <asm/io.h>
+
+/* Register offsets */
+#define UART_RX_REG 0x00
+
+#define UART_TX_REG 0x04
+
+#define UART_CTRL_REG 0x08
+#define CTRL_TXFIFO_RST BIT(15)
+#define CTRL_RXFIFO_RST BIT(14)
+#define CTRL_TX_RDY_INT BIT(5)
+#define CTRL_RX_RDY_INT BIT(4)
+#define CTRL_BRK_DET_INT BIT(3)
+#define CTRL_FRM_ERR_INT BIT(2)
+#define CTRL_PAR_ERR_INT BIT(1)
+#define CTRL_OVR_ERR_INT BIT(0)
+#define CTRL_ERR_INT (CTRL_BRK_DET_INT | CTRL_FRM_ERR_INT | \
+ CTRL_PAR_ERR_INT | CTRL_OVR_ERR_INT)
+
+#define UART_STATUS_REG 0x0c
+#define STATUS_TXFIFO_EMP BIT(13)
+#define STATUS_TXFIFO_FUL BIT(11)
+#define STATUS_TXFIFO_HFL BIT(10)
+#define STATUS_TX_RDY BIT(5)
+#define STATUS_RX_RDY BIT(4)
+#define STATUS_BRK_DET BIT(3)
+#define STATUS_FRM_ERR BIT(2)
+#define STATUS_PAR_ERR BIT(1)
+#define STATUS_OVR_ERR BIT(0)
+#define STATUS_BRK_ERR (STATUS_BRK_DET | STATUS_FRM_ERR | \
+ STATUS_PAR_ERR | STATUS_OVR_ERR)
+
+#define TX_FIFO_SIZE 32
+
+static struct mvebu3700_uart {
+ unsigned int irq;
+ void __iomem *regs;
+ struct irqaction irqaction;
+ struct vuart_info vuart;
+} mvebu3700_com = {0};
+
+#define mvebu3700_read(uart, off) readl((uart)->regs + off)
+#define mvebu3700_write(uart, off, val) writel(val, (uart->regs) + off)
+
+static void mvebu3700_uart_interrupt(int irq, void *data,
+ struct cpu_user_regs *regs)
+{
+ struct serial_port *port = data;
+ struct mvebu3700_uart *uart = port->uart;
+ uint32_t st = mvebu3700_read(uart, UART_STATUS_REG);
+
+ if ( st & (STATUS_RX_RDY | STATUS_OVR_ERR | STATUS_FRM_ERR |
+ STATUS_BRK_DET) )
+ serial_rx_interrupt(port, regs);
+
+ if ( st & STATUS_TX_RDY )
+ serial_tx_interrupt(port, regs);
+}
+
+static void __init mvebu3700_uart_init_preirq(struct serial_port *port)
+{
+ struct mvebu3700_uart *uart = port->uart;
+ uint32_t reg;
+
+ reg = mvebu3700_read(uart, UART_CTRL_REG);
+ reg |= (CTRL_TXFIFO_RST | CTRL_RXFIFO_RST);
+ mvebu3700_write(uart, UART_CTRL_REG, reg);
+
+ /* Before we make IRQ request, clear the error bits of state register. */
+ reg = mvebu3700_read(uart, UART_STATUS_REG);
+ reg |= STATUS_BRK_ERR;
+ mvebu3700_write(uart, UART_STATUS_REG, reg);
+
+ /* Clear error interrupts. */
+ mvebu3700_write(uart, UART_CTRL_REG, CTRL_ERR_INT);
+
+ /* Disable Rx/Tx interrupts. */
+ reg = mvebu3700_read(uart, UART_CTRL_REG);
+ reg &= ~(CTRL_RX_RDY_INT | CTRL_TX_RDY_INT);
+ mvebu3700_write(uart, UART_CTRL_REG, reg);
+}
+
+static void __init mvebu3700_uart_init_postirq(struct serial_port *port)
+{
+ struct mvebu3700_uart *uart = port->uart;
+ uint32_t reg;
+
+ uart->irqaction.handler = mvebu3700_uart_interrupt;
+ uart->irqaction.name = "mvebu3700_uart";
+ uart->irqaction.dev_id = port;
+
+ if ( setup_irq(uart->irq, 0, &uart->irqaction) != 0 )
+ {
+ printk("Failed to allocated mvebu3700_uart IRQ %d\n", uart->irq);
+ return;
+ }
+
+ /* Make sure Rx/Tx interrupts are enabled now */
+ reg = mvebu3700_read(uart, UART_CTRL_REG);
+ reg |= (CTRL_RX_RDY_INT | CTRL_TX_RDY_INT);
+ mvebu3700_write(uart, UART_CTRL_REG, reg);
+}
+
+static void mvebu3700_uart_suspend(struct serial_port *port)
+{
+ BUG();
+}
+
+static void mvebu3700_uart_resume(struct serial_port *port)
+{
+ BUG();
+}
+
+static void mvebu3700_uart_putc(struct serial_port *port, char c)
+{
+ struct mvebu3700_uart *uart = port->uart;
+
+ mvebu3700_write(uart, UART_TX_REG, c);
+}
+
+static int mvebu3700_uart_getc(struct serial_port *port, char *c)
+{
+ struct mvebu3700_uart *uart = port->uart;
+
+ if ( !(mvebu3700_read(uart, UART_STATUS_REG) & STATUS_RX_RDY) )
+ return 0;
+
+ *c = mvebu3700_read(uart, UART_RX_REG) & 0xff;
+
+ return 1;
+}
+
+static int __init mvebu3700_irq(struct serial_port *port)
+{
+ struct mvebu3700_uart *uart = port->uart;
+
+ return uart->irq;
+}
+
+static const struct vuart_info *mvebu3700_vuart_info(struct serial_port *port)
+{
+ struct mvebu3700_uart *uart = port->uart;
+
+ return &uart->vuart;
+}
+
+static void mvebu3700_uart_stop_tx(struct serial_port *port)
+{
+ struct mvebu3700_uart *uart = port->uart;
+ uint32_t reg;
+
+ reg = mvebu3700_read(uart, UART_CTRL_REG);
+ reg &= ~CTRL_TX_RDY_INT;
+ mvebu3700_write(uart, UART_CTRL_REG, reg);
+}
+
+static void mvebu3700_uart_start_tx(struct serial_port *port)
+{
+ struct mvebu3700_uart *uart = port->uart;
+ uint32_t reg;
+
+ reg = mvebu3700_read(uart, UART_CTRL_REG);
+ reg |= CTRL_TX_RDY_INT;
+ mvebu3700_write(uart, UART_CTRL_REG, reg);
+}
+
+static int mvebu3700_uart_tx_ready(struct serial_port *port)
+{
+ struct mvebu3700_uart *uart = port->uart;
+ uint32_t reg;
+
+ reg = mvebu3700_read(uart, UART_STATUS_REG);
+
+ if ( reg & STATUS_TXFIFO_EMP )
+ return TX_FIFO_SIZE;
+ if ( reg & STATUS_TXFIFO_FUL )
+ return 0;
+ if ( reg & STATUS_TXFIFO_HFL )
+ return TX_FIFO_SIZE / 2;
+
+ /*
+ * If we reach here, we don't know the number of free char in FIFO
+ * but we are sure that neither the FIFO is full nor empty.
+ * So, let's just return at least 1.
+ */
+ return 1;
+}
+
+static struct uart_driver __read_mostly mvebu3700_uart_driver = {
+ .init_preirq = mvebu3700_uart_init_preirq,
+ .init_postirq = mvebu3700_uart_init_postirq,
+ .endboot = NULL,
+ .suspend = mvebu3700_uart_suspend,
+ .resume = mvebu3700_uart_resume,
+ .putc = mvebu3700_uart_putc,
+ .getc = mvebu3700_uart_getc,
+ .tx_ready = mvebu3700_uart_tx_ready,
+ .stop_tx = mvebu3700_uart_stop_tx,
+ .start_tx = mvebu3700_uart_start_tx,
+ .irq = mvebu3700_irq,
+ .vuart_info = mvebu3700_vuart_info,
+};
+
+static int __init mvebu_uart_init(struct dt_device_node *dev, const void *data)
+{
+ const char *config = data;
+ struct mvebu3700_uart *uart;
+ int res;
+ u64 addr, size;
+
+ if ( strcmp(config, "") )
+ printk("WARNING: UART configuration is not supported\n");
+
+ uart = &mvebu3700_com;
+
+ res = dt_device_get_address(dev, 0, &addr, &size);
+ if ( res )
+ {
+ printk("mvebu3700: Unable to retrieve the base address of the UART\n");
+ return res;
+ }
+
+ res = platform_get_irq(dev, 0);
+ if ( res < 0 )
+ {
+ printk("mvebu3700: Unable to retrieve the IRQ\n");
+ return -EINVAL;
+ }
+
+ uart->irq = res;
+
+ uart->regs = ioremap_nocache(addr, size);
+ if ( !uart->regs )
+ {
+ printk("mvebu3700: Unable to map the UART memory\n");
+ return -ENOMEM;
+ }
+
+ uart->vuart.base_addr = addr;
+ uart->vuart.size = size;
+ uart->vuart.data_off = UART_CTRL_REG;
+ uart->vuart.status_off = UART_STATUS_REG;
+ uart->vuart.status = STATUS_TX_RDY | STATUS_RX_RDY;
+
+ /* Register with generic serial driver. */
+ serial_register_uart(SERHND_DTUART, &mvebu3700_uart_driver, uart);
+
+ dt_device_set_used_by(dev, DOMID_XEN);
+
+ return 0;
+}
+
+static const struct dt_device_match mvebu_dt_match[] __initconst =
+{
+ DT_MATCH_COMPATIBLE("marvell,armada-3700-uart"),
+ { /* sentinel */ },
+};
+
+DT_DEVICE_START(mvebu, "Marvell Armada-3700 UART", DEVICE_SERIAL)
+ .dt_match = mvebu_dt_match,
+ .init = mvebu_uart_init,
+DT_DEVICE_END
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
projects / people / iwj / xen.git / commitdiff