Hi Amit,
On 07/08/18 18:07, Amit Singh Tomar wrote:
This patch adds driver for UART controller present on Amlogic S905 SoC.
https://dn.odroid.com/S905/DataSheet/S905_Public_Datasheet_V1.1.4.pdf
The spec does not seems to provide the offset register. Where did you
find them?
Signed-off-by: Amit Singh Tomar <amittome...@gmail.com>
---
xen/drivers/char/Kconfig | 8 ++
xen/drivers/char/Makefile | 1 +
xen/drivers/char/meson-uart.c | 290 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 299 insertions(+)
create mode 100644 xen/drivers/char/meson-uart.c
diff --git a/xen/drivers/char/Kconfig b/xen/drivers/char/Kconfig
index cc78ec3..b9fee4e 100644
--- a/xen/drivers/char/Kconfig
+++ b/xen/drivers/char/Kconfig
@@ -20,6 +20,14 @@ config HAS_MVEBU
This selects the Marvell MVEBU UART. If you have a ARMADA 3700
based board, say Y.
+config HAS_MESON
+ bool
+ default y
+ depends on ARM_64
+ help
+ This selects the Marvell MESON UART. If you have a Amlogic S905
+ based board, say Y.
+
config HAS_PL011
bool
default y
diff --git a/xen/drivers/char/Makefile b/xen/drivers/char/Makefile
index b68c330..7c646d7 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-$(CONFIG_HAS_MESON) += meson-uart.o
obj-$(CONFIG_HAS_MVEBU) += mvebu-uart.o
obj-$(CONFIG_HAS_OMAP) += omap-uart.o
obj-$(CONFIG_HAS_SCIF) += scif-uart.o
diff --git a/xen/drivers/char/meson-uart.c b/xen/drivers/char/meson-uart.c
new file mode 100644
index 0000000..8fe7e62
--- /dev/null
+++ b/xen/drivers/char/meson-uart.c
@@ -0,0 +1,290 @@
+/*
+ * xen/drivers/char/meson-uart.c
+ *
+ * Driver for Amlogic MESON UART
+ *
+ * Copyright (c) 2018, Amit Singh Tomar <amittome...@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_WFIFO 0x00
+#define UART_RFIFO 0x04
+#define UART_CONTROL 0x08
+#define UART_STATUS 0x0c
+#define UART_MISC 0x10
+#define UART_REG5 0x14
+
+/* UART_CONTROL bits */
+#define UART_TX_EN BIT(12)
+#define UART_RX_EN BIT(13)
+#define UART_TX_RST BIT(22)
+#define UART_RX_RST BIT(23)
+#define UART_CLEAR_ERR BIT(24)
+#define UART_RX_INT_EN BIT(27)
+#define UART_TX_INT_EN BIT(28)
+
+/* UART_STATUS bits */
+#define UART_PARITY_ERR BIT(16)
+#define UART_FRAME_ERR BIT(17)
+#define UART_TX_FIFO_WERR BIT(18)
+#define UART_RX_EMPTY BIT(20)
+#define UART_TX_FULL BIT(21)
+#define UART_TX_EMPTY BIT(22)
+#define UART_TX_CNT_MASK GENMASK(14, 8)
+
+
+#define UART_XMIT_IRQ_CNT_MASK GENMASK(15, 8)
+#define UART_RECV_IRQ_CNT_MASK GENMASK(7, 0)
+
+#define TX_FIFO_SIZE 64
+
+static struct meson_s905_uart {
+ unsigned int irq;
+ void __iomem *regs;
+ struct irqaction irqaction;
+ struct vuart_info vuart;
+} meson_s905_com = {0};
AFAIK, {0} is not necessary.
+
+#define meson_s905_read(uart, off) readl((uart)->regs + off)
+#define meson_s905_write(uart, off, val) writel(val, (uart->regs) + off)
s/(uart->regs)/(uart)->regs/
+
+static void meson_s905_uart_interrupt(int irq, void *data,
+ struct cpu_user_regs *regs)
The indentation looks wrong here.
+{
+ struct serial_port *port = data;
+ struct meson_s905_uart *uart = port->uart;
+ uint32_t st = meson_s905_read(uart, UART_STATUS);
+
+ if ( !(st & UART_RX_EMPTY) )
+ {
+ serial_rx_interrupt(port, regs);
+ }
+
+ if ( !(st & UART_TX_FULL) )
+ {
+ if ( st & UART_TX_INT_EN )
+ serial_tx_interrupt(port, regs);
+ }
+
NIT: No need for this newline.
+}
+
+static void __init meson_s905_uart_init_preirq(struct serial_port *port)
+{
+ struct meson_s905_uart *uart = port->uart;
+ uint32_t reg;
+
+ reg = meson_s905_read(uart, UART_CONTROL);
+ reg &= ~(UART_RX_RST | UART_TX_RST | UART_CLEAR_ERR);
I am not sure why you are clearing those bits. AFAIU, init_preirq will
reset the serials, so you want to set thoses bits. This seems to be
confirmed by Linux in meson_uart_reset.
+ meson_s905_write(uart, UART_CONTROL, reg);
+
+ /* Disbale Rx/Tx interrupts */
s/Disbale/Disable/
+ reg = meson_s905_read(uart, UART_CONTROL);
+ reg &= ~(UART_RX_INT_EN | UART_TX_INT_EN);
+ meson_s905_write(uart, UART_CONTROL, reg);
+}
+
+static void __init meson_s905_uart_init_postirq(struct serial_port *port)
+{
+ struct meson_s905_uart *uart = port->uart;
+ uint32_t reg;
+
+ uart->irqaction.handler = meson_s905_uart_interrupt;
+ uart->irqaction.name = "meson_s905_uart";
+ uart->irqaction.dev_id = port;
+
+ if ( setup_irq(uart->irq, 0, &uart->irqaction) != 0 )
+ {
+ printk("Failed to allocated meson_s905_uart IRQ %d\n", uart->irq);
+ return;
+ }
+
+ /* Configure Rx/Tx interrupts based on bytes in FIFO */
+ reg = meson_s905_read(uart, UART_MISC);
You read UART_MISC here but ...
+ reg = (UART_RECV_IRQ_CNT_MASK & 1) |
... override the value here. You either want to drop reading UART_MISC
or add | here.
+ (UART_XMIT_IRQ_CNT_MASK & ((TX_FIFO_SIZE / 2) << 8));
This is a bit difficult to read. It feels like you want to use a macro
with a parameter that will do the correct masking.
+ meson_s905_write(uart, UART_MISC, reg);
+
+ /* Make sure Rx/Tx interrupts are enabled now */
+ reg = meson_s905_read(uart, UART_CONTROL);
+ reg |= (UART_RX_INT_EN | UART_TX_INT_EN);
+ meson_s905_write(uart, UART_CONTROL, reg);
+}
+
+static void meson_s905_uart_suspend(struct serial_port *port)
+{
+ BUG();
+}
+
+static void meson_s905_uart_resume(struct serial_port *port)
+{
+ BUG();
+}
+
+static void meson_s905_uart_putc(struct serial_port *port, char c)
+{
+ struct meson_s905_uart *uart = port->uart;
+
+ meson_s905_write(uart, UART_WFIFO, c);
+}
+
+static int meson_s905_uart_getc(struct serial_port *port, char *c)
+{
+ struct meson_s905_uart *uart = port->uart;
+
+ if ( (meson_s905_read(uart, UART_STATUS) & UART_RX_EMPTY) )
+ return 0;
+
+ *c = meson_s905_read(uart, UART_RFIFO) & 0xff;
+
+ return 1;
+}
+
+static int __init meson_s905_irq(struct serial_port *port)
+{
+ struct meson_s905_uart *uart = port->uart;
+
+ return uart->irq;
+}
+
+static const struct vuart_info *meson_s905_vuart_info(struct serial_port *port)
+{
+ struct meson_s905_uart *uart = port->uart;
+
+ return &uart->vuart;
+}
+
+static void meson_s905_uart_stop_tx(struct serial_port *port)
+{
+ struct meson_s905_uart *uart = port->uart;
+ uint32_t reg;
+
+ reg = meson_s905_read(uart, UART_CONTROL);
+ reg &= ~UART_TX_INT_EN;
+ meson_s905_write(uart, UART_CONTROL, reg);
+}
+
+static void meson_s905_uart_start_tx(struct serial_port *port)
+{
+ struct meson_s905_uart *uart = port->uart;
+ uint32_t reg;
+
+ reg = meson_s905_read(uart, UART_CONTROL);
+ reg |= UART_TX_INT_EN;
+ meson_s905_write(uart, UART_CONTROL, reg);
+}
+
+static int meson_s905_uart_tx_ready(struct serial_port *port)
+{
+ struct meson_s905_uart *uart = port->uart;
+ uint32_t reg;
+
+ reg = meson_s905_read(uart, UART_STATUS);
+
+ if ( reg & UART_TX_EMPTY )
+ return TX_FIFO_SIZE;
+ if ( reg & UART_TX_FULL )
+ return 0;
+
+ return (reg & UART_TX_CNT_MASK) >> 8;
+}
+
+static struct uart_driver __read_mostly meson_uart_driver = {
+ .init_preirq = meson_s905_uart_init_preirq,
+ .init_postirq = meson_s905_uart_init_postirq,
+ .endboot = NULL,
+ .suspend = meson_s905_uart_suspend,
+ .resume = meson_s905_uart_resume,
+ .putc = meson_s905_uart_putc,
+ .getc = meson_s905_uart_getc,
+ .tx_ready = meson_s905_uart_tx_ready,
+ .stop_tx = meson_s905_uart_stop_tx,
+ .start_tx = meson_s905_uart_start_tx,
+ .irq = meson_s905_irq,
+ .vuart_info = meson_s905_vuart_info,
+};
+
+static int __init meson_uart_init(struct dt_device_node *dev, const void *data)
+{
+ const char *config = data;
+ struct meson_s905_uart *uart;
+ int res;
+ u64 addr, size;
+
+ if ( strcmp(config, "") )
+ printk("WARNING: UART configuration is not supported\n");
+
+ uart = &meson_s905_com;
+
+ res = dt_device_get_address(dev, 0, &addr, &size);
+ if ( res )
+ {
+ printk("meson_s905: Unable to retrieve the base address of the
UART\n");
+ return res;
+ }
+
+ res = platform_get_irq(dev, 0);
+ if ( res < 0 )
+ {
+ printk("meson_s905: Unable to retrieve the IRQ\n");
+ return -EINVAL;
+ }
+
+ uart->irq = res;
+
+ uart->regs = ioremap_nocache(addr, size);
+ if ( !uart->regs )
+ {
+ printk("meson_s905: Unable to map the UART memory\n");
+ return -ENOMEM;
+ }
+
+ uart->vuart.base_addr = addr;
+ uart->vuart.size = size;
+ uart->vuart.data_off = UART_CONTROL;
+ uart->vuart.status_off = UART_STATUS;
+ uart->vuart.status = UART_RX_EMPTY | UART_TX_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"),
Looking at Linux, this is considered as a legacy bindings. Would not it
be better to use stable bindings in Xen?
Cheers,
--
Julien Grall
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