xen/arm: Add Cadence UART driver

Reviewed-by: Julien Grall <julien.grall@linaro.org>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>

config/arm64.mk

@@ -7,6 +7,7 @@ CONFIG_XEN_INSTALL_SUFFIX :=
 CFLAGS += #-marm -march= -mcpu= etc
 
 HAS_PL011 := y
+HAS_CADENCE_UART := y
 HAS_NS16550 := y
 
 # Use only if calling $(LD) directly.

xen/drivers/char/Makefile

@@ -1,5 +1,6 @@
 obj-y += console.o
 obj-$(HAS_NS16550) += ns16550.o
+obj-$(HAS_CADENCE_UART) += cadence-uart.o
 obj-$(HAS_PL011) += pl011.o
 obj-$(HAS_EXYNOS4210) += exynos4210-uart.o
 obj-$(HAS_OMAP) += omap-uart.o

xen/drivers/char/cadence-uart.c

@@ -0,0 +1,224 @@
+/*
+ * xen/drivers/char/cadence-uart.c
+ *
+ * Driver for Cadence UART in Xilinx ZynqMP.
+ *
+ * Written by Edgar E. Iglesias <edgar.iglesias@gmail.com>
+ * Copyright (c) 2015 Xilinx Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ */
+
+#include <xen/config.h>
+#include <xen/console.h>
+#include <xen/serial.h>
+#include <xen/init.h>
+#include <xen/irq.h>
+#include <xen/device_tree.h>
+#include <xen/errno.h>
+#include <asm/device.h>
+#include <xen/mm.h>
+#include <xen/vmap.h>
+#include <asm/cadence-uart.h>
+#include <asm/io.h>
+
+static struct cuart {
+    unsigned int irq;
+    void __iomem *regs;
+    /* UART with IRQ line: interrupt-driven I/O. */
+    struct irqaction irqaction;
+    struct vuart_info vuart;
+} cuart_com = {0};
+
+#define cuart_read(uart, off)           readl((uart)->regs + (off))
+#define cuart_write(uart, off,val)      writel((val), (uart)->regs + (off))
+
+static void cuart_interrupt(int irq, void *data, struct cpu_user_regs *regs)
+{
+    struct serial_port *port = data;
+    struct cuart *uart = port->uart;
+    unsigned int status;
+
+    do {
+        status = cuart_read(uart, R_UART_SR);
+        /* ACK.  */
+        if ( status & UART_SR_INTR_RTRIG )
+        {
+            serial_rx_interrupt(port, regs);
+            cuart_write(uart, R_UART_CISR, UART_SR_INTR_RTRIG);
+        }
+    } while ( status & UART_SR_INTR_RTRIG );
+}
+
+static void __init cuart_init_preirq(struct serial_port *port)
+{
+    struct cuart *uart = port->uart;
+
+    cuart_write(uart, R_UART_MR, UART_MR_NO_PARITY);
+    /* Enable and Reset both the RX and TX paths.  */
+    cuart_write(uart, R_UART_CR, UART_CR_RX_RST | UART_CR_TX_RST |
+                      UART_CR_RX_ENABLE | UART_CR_TX_ENABLE);
+}
+
+static void __init cuart_init_postirq(struct serial_port *port)
+{
+    struct cuart *uart = port->uart;
+    int rc;
+
+    if ( uart->irq > 0 )
+    {
+        uart->irqaction.handler = cuart_interrupt;
+        uart->irqaction.name    = "cadence-uart";
+        uart->irqaction.dev_id  = port;
+        if ( (rc = setup_irq(uart->irq, 0, &uart->irqaction)) != 0 )
+            printk("ERROR: Failed to allocate cadence-uart IRQ %d\n", uart->irq);
+    }
+
+    /* Clear pending error interrupts */
+    cuart_write(uart, R_UART_RTRIG, 1);
+    cuart_write(uart, R_UART_CISR, ~0);
+
+    /* Unmask interrupts */
+    cuart_write(uart, R_UART_IDR, ~0);
+    cuart_write(uart, R_UART_IER, UART_SR_INTR_RTRIG);
+}
+
+static void cuart_suspend(struct serial_port *port)
+{
+    BUG();
+}
+
+static void cuart_resume(struct serial_port *port)
+{
+    BUG();
+}
+
+static int cuart_tx_ready(struct serial_port *port)
+{
+    struct cuart *uart = port->uart;
+    unsigned int status = cuart_read(uart, R_UART_SR);
+
+    return !( status & UART_SR_INTR_TFUL );
+}
+
+static void cuart_putc(struct serial_port *port, char c)
+{
+    struct cuart *uart = port->uart;
+
+    cuart_write(uart, R_UART_TX, (uint32_t)(unsigned char)c);
+}
+
+static int cuart_getc(struct serial_port *port, char *pc)
+{
+    struct cuart *uart = port->uart;
+
+    if ( cuart_read(uart, R_UART_SR) & UART_SR_INTR_REMPTY )
+        return 0;
+
+    *pc = cuart_read(uart, R_UART_RX) & 0xff;
+    return 1;
+}
+
+static int __init cuart_irq(struct serial_port *port)
+{
+    struct cuart *uart = port->uart;
+
+    return ( (uart->irq > 0) ? uart->irq : -1 );
+}
+
+static const struct vuart_info *cuart_vuart(struct serial_port *port)
+{
+    struct cuart *uart = port->uart;
+
+    return &uart->vuart;
+}
+
+static struct uart_driver __read_mostly cuart_driver = {
+    .init_preirq  = cuart_init_preirq,
+    .init_postirq = cuart_init_postirq,
+    .endboot      = NULL,
+    .suspend      = cuart_suspend,
+    .resume       = cuart_resume,
+    .tx_ready     = cuart_tx_ready,
+    .putc         = cuart_putc,
+    .getc         = cuart_getc,
+    .irq          = cuart_irq,
+    .vuart_info   = cuart_vuart,
+};
+
+static int __init cuart_init(struct dt_device_node *dev, const void *data)
+{
+    const char *config = data;
+    struct cuart *uart;
+    int res;
+    u64 addr, size;
+
+    if ( strcmp(config, "") )
+        printk("WARNING: UART configuration is not supported\n");
+
+    uart = &cuart_com;
+
+    res = dt_device_get_address(dev, 0, &addr, &size);
+    if ( res )
+    {
+        printk("cadence: Unable to retrieve the base"
+               " address of the UART\n");
+        return res;
+    }
+
+    res = platform_get_irq(dev, 0);
+    if ( res < 0 )
+    {
+        printk("cadence: Unable to retrieve the IRQ\n");
+        return -EINVAL;
+    }
+    uart->irq = res;
+
+    uart->regs = ioremap_nocache(addr, size);
+    if ( !uart->regs )
+    {
+        printk("cadence: Unable to map the UART memory\n");
+        return -ENOMEM;
+    }
+
+    uart->vuart.base_addr = addr;
+    uart->vuart.size = size;
+    uart->vuart.data_off = R_UART_RX;
+    uart->vuart.status_off = R_UART_SR;
+    uart->vuart.status = UART_SR_INTR_TEMPTY;
+
+    /* Register with generic serial driver. */
+    serial_register_uart(SERHND_DTUART, &cuart_driver, uart);
+
+    dt_device_set_used_by(dev, DOMID_XEN);
+
+    return 0;
+}
+
+static const struct dt_device_match cuart_dt_match[] __initconst =
+{
+    DT_MATCH_COMPATIBLE("cdns,uart-r1p8"),
+    { /* sentinel */ },
+};
+
+DT_DEVICE_START(cuart, "Cadence UART", DEVICE_SERIAL)
+    .dt_match = cuart_dt_match,
+    .init = cuart_init,
+DT_DEVICE_END
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */

xen/include/asm-arm/cadence-uart.h

@@ -0,0 +1,55 @@
+/*
+ * xen/include/asm-arm/cadence-uart.h
+ *
+ * Written by Edgar E. Iglesias <edgar.iglesias@xilinx.com>
+ * Copyright (C) 2015 Xilinx Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ */
+
+#ifndef __ASM_ARM_CADENCE_UART_H__
+#define __ASM_ARM_CADENCE_UART_H__
+
+#define R_UART_CR    0x00
+#define UART_CR_RX_RST       0x01
+#define UART_CR_TX_RST       0x02
+#define UART_CR_RX_ENABLE    0x04
+#define UART_CR_RX_DISABLE   0x08
+#define UART_CR_TX_ENABLE    0x10
+#define UART_CR_TX_DISABLE   0x20
+
+#define R_UART_MR    0x04
+#define UART_MR_NO_PARITY    0x20
+
+#define R_UART_IER   0x08
+#define R_UART_IDR   0x0C
+#define R_UART_IMR   0x10
+#define R_UART_CISR  0x14
+#define R_UART_RTRIG 0x20
+#define R_UART_SR    0x2C
+#define UART_SR_INTR_RTRIG   0x01
+#define UART_SR_INTR_REMPTY  0x02
+#define UART_SR_INTR_TEMPTY  0x08
+#define UART_SR_INTR_TFUL    0x10
+
+#define R_UART_TX    0x30
+#define R_UART_RX    0x30
+
+#endif /* __ASM_ARM_CADENCE_UART_H */
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */