[PATCH v1] xen/arm: Add MVEBU UART driver for Armada 3700 SoC

* [PATCH v1] xen/arm: Add MVEBU UART driver for Armada 3700 SoC
@ 2018-03-16 17:34 Amit Singh Tomar
  2018-03-21 17:09 ` Wei Liu
  2018-03-30  0:46 ` André Przywara
  0 siblings, 2 replies; 7+ messages in thread
From: Amit Singh Tomar @ 2018-03-16 17:34 UTC (permalink / raw)
  To: xen-devel
  Cc: sstabellini, wei.liu2, George.Dunlap, andre.przywara,
	ian.jackson, tim, julien.grall, jbeulich, andrew.cooper3,
	Amit Singh Tomar

This patch adds driver for UART controller found on Armada 3700 SoC.

There is no reference manuals available for 3700 SoC in public and this
driver is derived by looking at Linux driver.
https://github.com/torvalds/linux/blob/master/drivers/tty/serial/mvebu-uart.c

It allows XEN to boot on ESPRESSObin board based on Marvell's ARMADA 3700 SoC.

Signed-off-by: Amit Singh Tomar <amittomer25@gmail.com>
---
Changes since RFC:
	* Addressed Julien's Comments. 
TODO:
	* Wiki page to capture XEN boot info.
	* earlyprintk support.
---
 xen/drivers/char/Kconfig         |   8 ++
 xen/drivers/char/Makefile        |   1 +
 xen/drivers/char/mvebu-uart.c    | 260 +++++++++++++++++++++++++++++++++++++++
 xen/include/asm-arm/mvebu-uart.h |  60 +++++++++
 4 files changed, 329 insertions(+)
 create mode 100644 xen/drivers/char/mvebu-uart.c
 create mode 100644 xen/include/asm-arm/mvebu-uart.h

diff --git a/xen/drivers/char/Kconfig b/xen/drivers/char/Kconfig
index fb53dd8..690eda6 100644
--- a/xen/drivers/char/Kconfig
+++ b/xen/drivers/char/Kconfig
@@ -12,6 +12,14 @@ config HAS_CADENCE_UART
 	  This selects the Xilinx Zynq Cadence UART. If you have a Xilinx Zynq
 	  based board, say Y.
 
+config HAS_MVEBU
+        bool
+        default y
+        depends on ARM_64
+        help
+          This selects the Marvell MVEBU UART. if you have an ARMADA 3700
+          based board, say Y.
+
 config HAS_PL011
 	bool
 	default y
diff --git a/xen/drivers/char/Makefile b/xen/drivers/char/Makefile
index 0d48b16..b68c330 100644
--- a/xen/drivers/char/Makefile
+++ b/xen/drivers/char/Makefile
@@ -3,6 +3,7 @@ obj-$(CONFIG_HAS_NS16550) += ns16550.o
 obj-$(CONFIG_HAS_CADENCE_UART) += cadence-uart.o
 obj-$(CONFIG_HAS_PL011) += pl011.o
 obj-$(CONFIG_HAS_EXYNOS4210) += exynos4210-uart.o
+obj-$(CONFIG_HAS_MVEBU) += mvebu-uart.o
 obj-$(CONFIG_HAS_OMAP) += omap-uart.o
 obj-$(CONFIG_HAS_SCIF) += scif-uart.o
 obj-$(CONFIG_HAS_EHCI) += ehci-dbgp.o
diff --git a/xen/drivers/char/mvebu-uart.c b/xen/drivers/char/mvebu-uart.c
new file mode 100644
index 0000000..c88d5e7
--- /dev/null
+++ b/xen/drivers/char/mvebu-uart.c
@@ -0,0 +1,260 @@
+/*
+ * xen/drivers/char/mvebu3700-uart.c
+ *
+ * Driver for Marvell MVEBU UART.
+ *
+ * Amit Singh Tomar <amittomer25@gmail.com>
+ * Copyright (c) 2018.
+ *
+ * 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/console.h>
+#include <xen/errno.h>
+#include <xen/init.h>
+#include <xen/irq.h>
+#include <xen/mm.h>
+#include <xen/serial.h>
+#include <xen/vmap.h>
+#include <asm/device.h>
+#include <asm/io.h>
+#include <asm/mvebu-uart.h>
+
+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_TX_RDY )
+        serial_tx_interrupt(port, regs);
+
+    if ( st & (STATUS_RX_RDY | STATUS_OVR_ERR | STATUS_FRM_ERR |
+               STATUS_BRK_DET) )
+        serial_rx_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_RX_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;
+
+    if ( uart->irq > 0 )
+    {
+        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 > 0) ? uart->irq : -1 );
+}
+
+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);
+
+    return ( reg & STATUS_TXFIFO_EMP ? TX_FIFO_SIZE : 0 );
+}
+
+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:
+ */
diff --git a/xen/include/asm-arm/mvebu-uart.h b/xen/include/asm-arm/mvebu-uart.h
new file mode 100644
index 0000000..0405b1d
--- /dev/null
+++ b/xen/include/asm-arm/mvebu-uart.h
@@ -0,0 +1,60 @@
+/*
+ * xen/include/asm-arm/mvebu-uart.h
+ *
+ * Amit Singh Tomar <amittomer25@gmail.com>
+ * Copyright (c) 2018.
+ *
+ * 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_MVEBU_UART_H__
+#define __ASM_ARM_MVEBU_UART_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_RX_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_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
+
+#endif /* __ASM_ARM_MVEBU_UART_H */
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
-- 
1.9.1


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