--- /dev/null
+/*
+ * xen/drivers/char/meson-uart.c
+ *
+ * Driver for Amlogic MESON UART
+ *
+ * Copyright (c) 2019, 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 AML_UART_WFIFO_REG 0x00
+#define AML_UART_RFIFO_REG 0x04
+#define AML_UART_CONTROL_REG 0x08
+#define AML_UART_STATUS_REG 0x0c
+#define AML_UART_MISC_REG 0x10
+
+/* UART_CONTROL bits */
+#define AML_UART_TX_RST BIT(22)
+#define AML_UART_RX_RST BIT(23)
+#define AML_UART_CLEAR_ERR BIT(24)
+#define AML_UART_RX_INT_EN BIT(27)
+#define AML_UART_TX_INT_EN BIT(28)
+
+/* UART_STATUS bits */
+#define AML_UART_RX_FIFO_EMPTY BIT(20)
+#define AML_UART_TX_FIFO_FULL BIT(21)
+#define AML_UART_TX_FIFO_EMPTY BIT(22)
+#define AML_UART_TX_CNT_MASK GENMASK(14, 8)
+
+/* AML_UART_MISC bits */
+#define AML_UART_XMIT_IRQ(c) (((c) & 0xff) << 8)
+#define AML_UART_RECV_IRQ(c) ((c) & 0xff)
+
+#define TX_FIFO_SIZE 64
+
+#define setbits(addr, set) writel((readl(addr) | (set)), (addr))
+#define clrbits(addr, clear) writel((readl(addr) & ~(clear)), (addr))
+
+static struct meson_uart {
+ unsigned int irq;
+ void __iomem *regs;
+ struct irqaction irqaction;
+ struct vuart_info vuart;
+} meson_com;
+
+static void meson_uart_interrupt(int irq, void *data,
+ struct cpu_user_regs *regs)
+{
+ struct serial_port *port = data;
+ struct meson_uart *uart = port->uart;
+ uint32_t st = readl(uart->regs + AML_UART_STATUS_REG);
+
+ if ( !(st & AML_UART_RX_FIFO_EMPTY) )
+ serial_rx_interrupt(port, regs);
+
+ if ( !(st & AML_UART_TX_FIFO_FULL) )
+ serial_tx_interrupt(port, regs);
+}
+
+static void __init meson_uart_init_preirq(struct serial_port *port)
+{
+ struct meson_uart *uart = port->uart;
+
+ /* Reset UART */
+ setbits(uart->regs + AML_UART_CONTROL_REG,
+ (AML_UART_RX_RST | AML_UART_TX_RST | AML_UART_CLEAR_ERR));
+
+ clrbits(uart->regs + AML_UART_CONTROL_REG,
+ (AML_UART_RX_RST | AML_UART_TX_RST | AML_UART_CLEAR_ERR));
+
+ /* Disable Rx/Tx interrupts */
+ clrbits(uart->regs + AML_UART_CONTROL_REG,
+ (AML_UART_RX_INT_EN | AML_UART_TX_INT_EN));
+}
+
+static void __init meson_uart_init_postirq(struct serial_port *port)
+{
+ struct meson_uart *uart = port->uart;
+
+ uart->irqaction.handler = meson_uart_interrupt;
+ uart->irqaction.name = "meson_uart";
+ uart->irqaction.dev_id = port;
+
+ if ( setup_irq(uart->irq, 0, &uart->irqaction) != 0 )
+ {
+ printk("Failed to allocated Meson UART IRQ %d\n", uart->irq);
+ return;
+ }
+
+ /*
+ * Configure Rx/Tx interrupts based on bytes in FIFO, these bits have
+ * taken from Linux driver
+ */
+ writel((AML_UART_RECV_IRQ(1) | AML_UART_XMIT_IRQ(TX_FIFO_SIZE / 2)),
+ uart->regs + AML_UART_MISC_REG);
+
+ /* Make sure Rx/Tx interrupts are enabled now */
+ setbits(uart->regs + AML_UART_CONTROL_REG,
+ (AML_UART_RX_INT_EN | AML_UART_TX_INT_EN));
+}
+
+static void meson_uart_suspend(struct serial_port *port)
+{
+ BUG();
+}
+
+static void meson_uart_resume(struct serial_port *port)
+{
+ BUG();
+}
+
+static void meson_uart_putc(struct serial_port *port, char c)
+{
+ struct meson_uart *uart = port->uart;
+
+ writel(c, uart->regs + AML_UART_WFIFO_REG);
+}
+
+static int meson_uart_getc(struct serial_port *port, char *c)
+{
+ struct meson_uart *uart = port->uart;
+
+ if ( (readl(uart->regs + AML_UART_STATUS_REG) & AML_UART_RX_FIFO_EMPTY) )
+ return 0;
+
+ *c = readl(uart->regs + AML_UART_RFIFO_REG) & 0xff;
+
+ return 1;
+}
+
+static int __init meson_irq(struct serial_port *port)
+{
+ struct meson_uart *uart = port->uart;
+
+ return uart->irq;
+}
+
+static const struct vuart_info *meson_vuart_info(struct serial_port *port)
+{
+ struct meson_uart *uart = port->uart;
+
+ return &uart->vuart;
+}
+
+static void meson_uart_stop_tx(struct serial_port *port)
+{
+ struct meson_uart *uart = port->uart;
+
+ clrbits(uart->regs + AML_UART_CONTROL_REG, AML_UART_TX_INT_EN);
+}
+
+static void meson_uart_start_tx(struct serial_port *port)
+{
+ struct meson_uart *uart = port->uart;
+
+ setbits(uart->regs + AML_UART_CONTROL_REG, AML_UART_TX_INT_EN);
+}
+
+static int meson_uart_tx_ready(struct serial_port *port)
+{
+ struct meson_uart *uart = port->uart;
+ uint32_t reg;
+
+ reg = readl(uart->regs + AML_UART_STATUS_REG);
+
+ if ( reg & AML_UART_TX_FIFO_EMPTY )
+ return TX_FIFO_SIZE;
+ if ( reg & AML_UART_TX_FIFO_FULL )
+ return 0;
+
+ return (reg & AML_UART_TX_CNT_MASK) >> 8;
+}
+
+static struct uart_driver __read_mostly meson_uart_driver = {
+ .init_preirq = meson_uart_init_preirq,
+ .init_postirq = meson_uart_init_postirq,
+ .endboot = NULL,
+ .suspend = meson_uart_suspend,
+ .resume = meson_uart_resume,
+ .putc = meson_uart_putc,
+ .getc = meson_uart_getc,
+ .tx_ready = meson_uart_tx_ready,
+ .stop_tx = meson_uart_stop_tx,
+ .start_tx = meson_uart_start_tx,
+ .irq = meson_irq,
+ .vuart_info = meson_vuart_info,
+};
+
+static int __init meson_uart_init(struct dt_device_node *dev, const void *data)
+{
+ const char *config = data;
+ struct meson_uart *uart;
+ int res;
+ u64 addr, size;
+
+ if ( strcmp(config, "") )
+ printk("WARNING: UART configuration is not supported\n");
+
+ uart = &meson_com;
+
+ res = dt_device_get_address(dev, 0, &addr, &size);
+ if ( res )
+ {
+ printk("meson: Unable to retrieve the base address of the UART\n");
+ return res;
+ }
+
+ res = platform_get_irq(dev, 0);
+ if ( res < 0 )
+ {
+ printk("meson: Unable to retrieve the IRQ\n");
+ return -EINVAL;
+ }
+
+ uart->irq = res;
+
+ uart->regs = ioremap_nocache(addr, size);
+ if ( !uart->regs )
+ {
+ printk("meson: Unable to map the UART\n");
+ return -ENOMEM;
+ }
+
+ uart->vuart.base_addr = addr;
+ uart->vuart.size = size;
+ uart->vuart.data_off = AML_UART_WFIFO_REG;
+ uart->vuart.status_off = AML_UART_STATUS_REG;
+ uart->vuart.status = AML_UART_RX_FIFO_EMPTY | AML_UART_TX_FIFO_EMPTY;
+
+ /* Register with generic serial driver. */
+ serial_register_uart(SERHND_DTUART, &meson_uart_driver, uart);
+
+ dt_device_set_used_by(dev, DOMID_XEN);
+
+ return 0;
+}
+
+static const struct dt_device_match meson_dt_match[] __initconst =
+{
+ DT_MATCH_COMPATIBLE("amlogic,meson-uart"),
+ DT_MATCH_COMPATIBLE("amlogic,meson6-uart"),
+ DT_MATCH_COMPATIBLE("amlogic,meson8-uart"),
+ DT_MATCH_COMPATIBLE("amlogic,meson8b-uart"),
+ DT_MATCH_COMPATIBLE("amlogic,meson-gx-uart"),
+ { /* sentinel */ },
+};
+
+DT_DEVICE_START(meson, "Amlogic UART", DEVICE_SERIAL)
+ .dt_match = meson_dt_match,
+ .init = meson_uart_init,
+DT_DEVICE_END
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+*/
projects / people / sstabellini / xen-unstable.git / .git / commitdiff