Classification: Confidential
This driver patch adds the UART TTY serial support for the RISC-V based InCore Semiconductor's Chromite SoC family like Chromite M, Chromite H.
Signed-off-by: Sathish Kumar Balasubramaniam <b-sathishkumar@xxxxxxx>
---
drivers/tty/serial/Kconfig | 25 +
drivers/tty/serial/Makefile | 1 +
drivers/tty/serial/chromite_uart.c | 764 +++++++++++++++++++++++++++++
include/uapi/linux/serial_core.h | 3 +
4 files changed, 793 insertions(+)
create mode 100644 drivers/tty/serial/chromite_uart.c
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 24282ad99d85..f238bdb04ba6 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1009,6 +1009,31 @@ config SERIAL_SIFIVE_CONSOLE
your boot loader about how to pass options to the kernel at
boot time.)
+config SERIAL_CHROMITE
+ tristate "Chromite UART support"
+ depends on OF
+ select SERIAL_CORE
+ help
+ Select this option if you are building a kernel for a device that
+ contains a Chromite UART IP block. This type of UART is present on
+ Chromite-H SoC, among others.
+
+config SERIAL_CHROMITE_CONSOLE
+ bool "Console on Chromite UART"
+ depends on SERIAL_CHROMITE=y
+ select SERIAL_CORE_CONSOLE
+ select SERIAL_EARLYCON
+ help
+ Select this option if you would like to use a Chromite UART as the
+ system console.
+
+ Even if you say Y here, the currently visible virtual console
+ (/dev/tty0) will still be used as the system console by default, but
+ you can alter that using a kernel command line option such as
+ "console=ttyCRMTx". (Try "man bootparam" or see the documentation of
+ your boot loader about how to pass options to the kernel at
+ boot time.)
+
config SERIAL_LANTIQ
tristate "Lantiq serial driver"
depends on (LANTIQ || X86) || COMPILE_TEST
diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
index 7da0856cd198..dd0acc512714 100644
--- a/drivers/tty/serial/Makefile
+++ b/drivers/tty/serial/Makefile
@@ -86,6 +86,7 @@ obj-$(CONFIG_SERIAL_OWL) += owl-uart.o
obj-$(CONFIG_SERIAL_RDA) += rda-uart.o
obj-$(CONFIG_SERIAL_MILBEAUT_USIO) += milbeaut_usio.o
obj-$(CONFIG_SERIAL_SIFIVE) += sifive.o
+obj-$(CONFIG_SERIAL_CHROMITE) += chromite_uart.o
obj-$(CONFIG_SERIAL_LITEUART) += liteuart.o
# GPIOLIB helpers for modem control lines
diff --git a/drivers/tty/serial/chromite_uart.c b/drivers/tty/serial/chromite_uart.c
new file mode 100644
index 000000000000..0e9da1d0d725
--- /dev/null
+++ b/drivers/tty/serial/chromite_uart.c
@@ -0,0 +1,764 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Chromite UART driver
+ * Copyright (C) 2021 Sathish Kumar Balasubramaniam <b-sathishkumar@xxxxxxx>
+ * Copyright (C) 2021 InCore Semiconductors
+ *
+ * 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.
+ *
+ * Based on:
+ * - drivers/tty/serial/sifive.c
+ *
+ * See the following sources for documentation
+ * - https://chromiteh-soc.readthedocs.io/en/latest/uart.html
+ * - https://chromitem-soc.readthedocs.io/en/latest/uart.html
+ *
+ * Presently the Chromite UART supports only the following configuration
+ * 8-N-1: 8 data bits, no parity and 1 stop-bit
+ *
+ * Presently the Chromite UART does not have support for hardware flow control or other modem control signals
+ *
+ *
+ */
+
+
+#include <linux/clk.h>
+#include <linux/console.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/serial_core.h>
+#include <linux/serial_reg.h>
+#include <linux/slab.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+
+
+#define CHROMITE_SERIAL_MAX_PORTS 1
+#define CHROMITE_DEFAULT_BAUD_RATE 115200
+#define CHROMITE_TTY_PREFIX "ttyCRMT"
+#define CHROMITE_CLOCK 50000000
+#define TX_FIFO_DEPTH 16
+#define RX_FIFO_DEPTH 16
+
+#define BAUD_REG_OFF 0x00
+#define TX_DATA_REG_OFF 0x04
+#define RX_DATA_REG_OFF 0x08
+#define STATUS_REG_OFF 0x0C
+#define CONTROL_REG_OFF 0x10
+#define STATUS_CLEAR_REG_OFF 0x14
+#define INT_EN_REG_OFF 0x18
+
+#define STATUS_REG_TX_NOTFULL_MASK 0x02
+#define STATUS_REG_RX_NOTEMPTY_MASK 0x08
+#define STATUS_REG_TX_THLD_HIT_MASK 0x10
+#define STATUS_REG_RX_THLD_HIT_MASK 0x20
+
+#define CONTROL_REG_TX_THLD_AUTO_RST_SHIFT 10
+#define CONTROL_REG_RX_THLD_AUTO_RST_SHIFT 11
+#define CONTROL_REG_TX_THLD_MASK 0xF0000
+#define CONTROL_REG_RX_THLD_MASK 0xF00000
+#define CONTROL_REG_STOP_BITS_MASK 0x3
+#define CONTROL_REG_STOP_BITS_SHIFT 0
+
+#define STATUS_CLEAR_TX_THLD_HIT 0x10
+#define STATUS_CLEAR_RX_THLD_HIT 0x20
+
+#define INT_EN_TX_THLD_HIT_MASK 0x10
+#define INT_EN_RX_THLD_HIT_MASK 0x20
+
+
+struct chromite_serial_port {
+ struct uart_port port;
+ unsigned long clkin_rate;
+ unsigned long baud_rate;
+ unsigned char cread_flag;
+ struct device *dev;
+};
+
+#define port_to_chromite_serial_port(p) (container_of((p), \
+ struct chromite_serial_port, \
+ port))
+
+static void chromite_serial_stop_tx(struct uart_port *port);
+
+static int chromite_serial_is_tx_fifo_full(struct chromite_serial_port *csp)
+{
+ u32 ret = 0;
+
+ ret = readl_relaxed(csp->port.membase + STATUS_REG_OFF);
+ if ((ret & STATUS_REG_TX_NOTFULL_MASK) == 0)
+ return 1;
+
+ return 0;
+}
+
+static void chromite_serial_wait_for_xmitr(struct chromite_serial_port *csp)
+{
+ while (chromite_serial_is_tx_fifo_full(csp))
+ udelay(1);
+}
+
+static void chromite_serial_transmit_char(struct chromite_serial_port *csp,
+ unsigned char ch)
+{
+ writeb_relaxed(ch, csp->port.membase + TX_DATA_REG_OFF);
+}
+
+static void chromite_serial_transmit_chars(struct chromite_serial_port *csp)
+{
+ struct circ_buf *xmit = &csp->port.state->xmit;
+ int count = 0;
+
+ if (csp->port.x_char) {
+ chromite_serial_transmit_char(csp, csp->port.x_char);
+ csp->port.icount.tx++;
+ csp->port.x_char = 0;
+ return;
+ }
+ if (uart_circ_empty(xmit) || uart_tx_stopped(&csp->port)) {
+ chromite_serial_stop_tx(&csp->port);
+ return;
+ }
+ count = TX_FIFO_DEPTH;
+ do {
+ chromite_serial_transmit_char(csp, xmit->buf[xmit->tail]);
+ xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+ csp->port.icount.tx++;
+ if (uart_circ_empty(xmit))
+ break;
+ } while (--count > 0);
+
+ if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+ uart_write_wakeup(&csp->port);
+
+ if (uart_circ_empty(xmit))
+ chromite_serial_stop_tx(&csp->port);
+
+}
+
+static void chromite_serial_enable_tx_thld_hit(
+ struct chromite_serial_port *csp)
+{
+ u16 val = 0;
+
+ val = readw_relaxed(csp->port.membase + INT_EN_REG_OFF);
+ if (val & INT_EN_TX_THLD_HIT_MASK)
+ return;
+
+ val |= INT_EN_TX_THLD_HIT_MASK;
+ writew_relaxed(val, csp->port.membase + INT_EN_REG_OFF);
+}
+
+static void chromite_serial_disable_tx_thld_hit(
+ struct chromite_serial_port *csp)
+{
+ u16 val = 0;
+
+ val = readw_relaxed(csp->port.membase + INT_EN_REG_OFF);
+ if ((val & INT_EN_TX_THLD_HIT_MASK) == 0)
+ return;
+
+ val &= ~INT_EN_TX_THLD_HIT_MASK;
+ writew_relaxed(val, csp->port.membase + INT_EN_REG_OFF);
+}
+
+static void chromite_serial_enable_rx_thld_hit(
+ struct chromite_serial_port *csp)
+{
+ u16 val = 0;
+
+ val = readw_relaxed(csp->port.membase + INT_EN_REG_OFF);
+ if (val & INT_EN_RX_THLD_HIT_MASK)
+ return;
+
+ val |= INT_EN_RX_THLD_HIT_MASK;
+ writew_relaxed(val, csp->port.membase + INT_EN_REG_OFF);
+}
+
+static void chromite_serial_disable_rx_thld_hit(
+ struct chromite_serial_port *csp)
+{
+ u16 val = 0;
+
+ val = readw_relaxed(csp->port.membase + INT_EN_REG_OFF);
+ if ((val & INT_EN_RX_THLD_HIT_MASK) == 0)
+ return;
+
+ val &= ~INT_EN_RX_THLD_HIT_MASK;
+ writew_relaxed(val, csp->port.membase + INT_EN_REG_OFF);
+}
+
+static int chromite_serial_receive_char(struct chromite_serial_port *csp,
+ unsigned char *ch)
+{
+ u32 val = 0;
+
+ if (!ch) {
+ BUG_ON(1);
+ return (-1);
+ }
+
+ val = readl_relaxed(csp->port.membase + STATUS_REG_OFF);
+
+ // check if rx FIFO is empty
+ if ((val & STATUS_REG_RX_NOTEMPTY_MASK) == 0)
+ return 1;
+
+ // if CREAD is not set in TERMIOS, then ignore the receive characters
+ if (csp->cread_flag == 0)
+ return 1;
+
+ *ch = readb_relaxed(csp->port.membase + RX_DATA_REG_OFF);
+
+ return 0;
+}
+
+static void chromite_serial_receive_chars(struct chromite_serial_port *csp)
+{
+ int i = 0;
+ unsigned char ch = 0;
+
+ for (i = 0; i < RX_FIFO_DEPTH; i++) {
+ if (chromite_serial_receive_char(csp, &ch) == 0) {
+ csp->port.icount.rx++;
+ uart_insert_char(&csp->port, 0, 0, ch, TTY_NORMAL);
+ } else {
+ break;
+ }
+ }
+
+ spin_unlock(&csp->port.lock);
+ tty_flip_buffer_push(&csp->port.state->port);
+ spin_lock(&csp->port.lock);
+}
+
+static void chromite_serial_update_div(struct chromite_serial_port *csp)
+{
+ u16 div;
+
+ div = csp->clkin_rate / (16 * csp->baud_rate);
+ writew_relaxed(div, csp->port.membase + BAUD_REG_OFF);
+}
+
+static void chromite_serial_update_baud_rate(struct chromite_serial_port *csp,
+ unsigned int rate)
+{
+ if (csp->baud_rate == rate)
+ return;
+
+ csp->baud_rate = rate;
+ chromite_serial_update_div(csp);
+}
+
+static void chromite_serial_stop_tx(struct uart_port *port)
+{
+ struct chromite_serial_port *csp = port_to_chromite_serial_port(port);
+
+ chromite_serial_disable_tx_thld_hit(csp);
+}
+
+static void chromite_serial_stop_rx(struct uart_port *port)
+{
+ struct chromite_serial_port *csp = port_to_chromite_serial_port(port);
+
+ chromite_serial_disable_rx_thld_hit(csp);
+}
+
+static void chromite_serial_start_tx(struct uart_port *port)
+{
+ struct chromite_serial_port *csp = port_to_chromite_serial_port(port);
+
+ chromite_serial_enable_tx_thld_hit(csp);
+}
+
+static irqreturn_t chromite_serial_irq(int irq, void *dev_id)
+{
+ struct chromite_serial_port *csp = dev_id;
+ u32 status_reg;
+
+ spin_lock(&csp->port.lock);
+
+ status_reg = readl_relaxed(csp->port.membase + STATUS_REG_OFF);
+
+ if ((status_reg & (STATUS_REG_RX_THLD_HIT_MASK |
+ STATUS_REG_TX_THLD_HIT_MASK)) == 0) {
+ spin_unlock(&csp->port.lock);
+ return IRQ_NONE;
+ }
+ if (status_reg & STATUS_REG_RX_THLD_HIT_MASK) {
+ chromite_serial_receive_chars(csp);
+ writeb_relaxed(STATUS_CLEAR_RX_THLD_HIT, csp->port.membase +
+ STATUS_CLEAR_REG_OFF);
+ }
+ if (status_reg & STATUS_REG_TX_THLD_HIT_MASK) {
+ chromite_serial_transmit_chars(csp);
+ writeb_relaxed(STATUS_CLEAR_TX_THLD_HIT, csp->port.membase +
+ STATUS_CLEAR_REG_OFF);
+ }
+
+ spin_unlock(&csp->port.lock);
+
+ return IRQ_HANDLED;
+}
+
+
+static unsigned int chromite_serial_tx_empty(struct uart_port *port)
+{
+ return TIOCSER_TEMT;
+}
+
+static unsigned int chromite_serial_get_mctrl(struct uart_port *port)
+{
+ return TIOCM_CAR | TIOCM_CTS | TIOCM_DSR;
+}
+
+static void chromite_serial_set_mctrl(struct uart_port *port,
+ unsigned int mctrl)
+{
+ /* No support */
+}
+
+static void chromite_serial_break_ctl(struct uart_port *port, int break_state)
+{
+ /* No support */
+}
+
+static int chromite_serial_startup(struct uart_port *port)
+{
+ struct chromite_serial_port *csp = port_to_chromite_serial_port(port);
+
+ chromite_serial_enable_rx_thld_hit(csp);
+
+ return 0;
+}
+
+static void chromite_serial_shutdown(struct uart_port *port)
+{
+ struct chromite_serial_port *csp = port_to_chromite_serial_port(port);
+
+ chromite_serial_disable_rx_thld_hit(csp);
+ chromite_serial_disable_tx_thld_hit(csp);
+}
+
+static void chromite_serial_set_termios(struct uart_port *port,
+ struct ktermios *termios,
+ struct ktermios *old)
+{
+ struct chromite_serial_port *csp = port_to_chromite_serial_port(port);
+ unsigned long flags;
+ int rate;
+
+ if ((termios->c_cflag & CSIZE) != CS8)
+ dev_err_once(csp->port.dev, "only 8-bit words supported\n");
+ if (termios->c_cflag & CSTOPB)
+ dev_err_once(csp->port.dev, "only 1 stop-bit is supported\n");
+ if (termios->c_iflag & (INPCK | PARMRK))
+ dev_err_once(csp->port.dev, "parity checking not supported\n");
+ if (termios->c_iflag & BRKINT)
+ dev_err_once(csp->port.dev, "BREAK detection not supported\n");
+
+ /* Set line rate */
+ rate = uart_get_baud_rate(port, termios, old, 0, csp->clkin_rate / 16);
+ chromite_serial_update_baud_rate(csp, rate);
+
+ spin_lock_irqsave(&csp->port.lock, flags);
+
+ /* Update the per-port timeout */
+ uart_update_timeout(port, termios->c_cflag, rate);
+
+ csp->port.read_status_mask = 0;
+
+ /* Ignore all characters if CREAD is not set */
+ if ((termios->c_cflag & CREAD) == 0)
+ csp->cread_flag = 0;
+ else
+ csp->cread_flag = 1;
+
+ spin_unlock_irqrestore(&csp->port.lock, flags);
+}
+
+static void chromite_serial_release_port(struct uart_port *port)
+{
+}
+
+static int chromite_serial_request_port(struct uart_port *port)
+{
+ return 0;
+}
+
+static void chromite_serial_config_port(struct uart_port *port, int flags)
+{
+ struct chromite_serial_port *csp = port_to_chromite_serial_port(port);
+
+ csp->port.type = PORT_CHROMITE;
+}
+
+static int chromite_serial_verify_port(struct uart_port *port,
+ struct serial_struct *ser)
+{
+ return -EINVAL;
+}
+
+static const char *chromite_serial_type(struct uart_port *port)
+{
+ return port->type == PORT_CHROMITE ? "Chromite UART" : NULL;
+}
+
+#ifdef CONFIG_CONSOLE_POLL
+static int chromite_serial_poll_get_char(struct uart_port *port)
+{
+ struct chromite_serial_port *csp = port_to_chromite_serial_port(port);
+ char ch;
+
+ if (chromite_serial_receive_char(csp, &ch) != 0)
+ return NO_POLL_CHAR;
+
+ return ch;
+}
+
+static void chromite_serial_poll_put_char(struct uart_port *port,
+ unsigned char c)
+{
+ struct chromite_serial_port *csp = port_to_chromite_serial_port(port);
+
+ chromite_serial_wait_for_xmitr(csp);
+ chromite_serial_transmit_char(csp, c);
+}
+#endif /* CONFIG_CONSOLE_POLL */
+
+/*
+ * Early console support
+ */
+
+#ifdef CONFIG_SERIAL_EARLYCON
+static void early_chromite_serial_putc(struct uart_port *port, int c)
+{
+ while ((readl_relaxed(port->membase + STATUS_REG_OFF) &
+ STATUS_REG_TX_NOTFULL_MASK) == 0)
+ cpu_relax();
+
+ writeb_relaxed(c, port->membase + TX_DATA_REG_OFF);
+}
+
+static void early_chromite_serial_write(struct console *con, const char *s,
+ unsigned int n)
+{
+ struct earlycon_device *dev = con->data;
+ struct uart_port *port = &dev->port;
+
+ uart_console_write(port, s, n, early_chromite_serial_putc);
+}
+
+static int __init early_chromite_serial_setup(struct earlycon_device *dev,
+ const char *options)
+{
+ struct uart_port *port = &dev->port;
+
+ if (!port->membase)
+ return -ENODEV;
+
+ dev->con->write = early_chromite_serial_write;
+
+ return 0;
+}
+
+OF_EARLYCON_DECLARE(chromite, "chromite,uart0", early_chromite_serial_setup);
+#endif /* CONFIG_SERIAL_EARLYCON */
+
+/*
+ * Linux console interface
+ */
+
+#ifdef CONFIG_SERIAL_CHROMITE_CONSOLE
+
+static struct chromite_serial_port *chromite_serial_console_ports[CHROMITE_SERIAL_MAX_PORTS];
+
+static void chromite_serial_console_putchar(struct uart_port *port, int ch)
+{
+ struct chromite_serial_port *csp = port_to_chromite_serial_port(port);
+
+ chromite_serial_wait_for_xmitr(csp);
+ chromite_serial_transmit_char(csp, ch);
+}
+
+static void chromite_serial_console_write(struct console *co, const char *s,
+ unsigned int count)
+{
+ struct chromite_serial_port *csp = chromite_serial_console_ports[co->index];
+ unsigned long flags;
+ u16 ier;
+ int locked = 1;
+
+ if (!csp)
+ return;
+
+ local_irq_save(flags);
+ if (csp->port.sysrq)
+ locked = 0;
+ else if (oops_in_progress)
+ locked = spin_trylock(&csp->port.lock);
+ else
+ spin_lock(&csp->port.lock);
+
+ ier = readw_relaxed(csp->port.membase + INT_EN_REG_OFF);
+ writew_relaxed(0, csp->port.membase + INT_EN_REG_OFF);
+
+ uart_console_write(&csp->port, s, count, chromite_serial_console_putchar);
+
+ writew_relaxed(ier, csp->port.membase + INT_EN_REG_OFF);
+
+ if (locked)
+ spin_unlock(&csp->port.lock);
+ local_irq_restore(flags);
+}
+
+static int __init chromite_serial_console_setup(struct console *co, char *options)
+{
+ struct chromite_serial_port *csp;
+ int baud = CHROMITE_DEFAULT_BAUD_RATE;
+ int bits = 8;
+ int parity = 'n';
+ int flow = 'n';
+
+ if (co->index < 0 || co->index >= CHROMITE_SERIAL_MAX_PORTS)
+ return -ENODEV;
+
+ csp = chromite_serial_console_ports[co->index];
+ if (!csp)
+ return -ENODEV;
+
+ if (options)
+ uart_parse_options(options, &baud, &parity, &bits, &flow);
+
+ return uart_set_options(&csp->port, co, baud, parity, bits, flow);
+}
+
+static struct uart_driver chromite_serial_uart_driver;
+
+static struct console chromite_serial_console = {
+ .name = CHROMITE_TTY_PREFIX,
+ .write = chromite_serial_console_write,
+ .device = uart_console_device,
+ .setup = chromite_serial_console_setup,
+ .flags = CON_PRINTBUFFER,
+ .index = -1,
+ .data = &chromite_serial_uart_driver,
+};
+
+static int __init chromite_console_init(void)
+{
+ register_console(&chromite_serial_console);
+ return 0;
+}
+
+console_initcall(chromite_console_init);
+
+static void chromite_add_console_port(struct chromite_serial_port *csp)
+{
+ chromite_serial_console_ports[csp->port.line] = csp;
+}
+
+static void chromite_remove_console_port(struct chromite_serial_port *csp)
+{
+ chromite_serial_console_ports[csp->port.line] = 0;
+}
+
+#define CHROMITE_SERIAL_CONSOLE (&chromite_serial_console)
+
+#else
+
+#define CHROMITE_SERIAL_CONSOLE NULL
+
+static void chromite_add_console_port(struct chromite_serial_port *csp)
+{}
+static void chromite_remove_console_port(struct chromite_serial_port *csp)
+{}
+
+#endif /* CONFIG_SERIAL_CHROMITE_CONSOLE */
+
+static const struct uart_ops chromite_serial_uart_ops = {
+ .tx_empty = chromite_serial_tx_empty,
+ .set_mctrl = chromite_serial_set_mctrl,
+ .get_mctrl = chromite_serial_get_mctrl,
+ .stop_tx = chromite_serial_stop_tx,
+ .start_tx = chromite_serial_start_tx,
+ .stop_rx = chromite_serial_stop_rx,
+ .break_ctl = chromite_serial_break_ctl,
+ .startup = chromite_serial_startup,
+ .shutdown = chromite_serial_shutdown,
+ .set_termios = chromite_serial_set_termios,
+ .type = chromite_serial_type,
+ .release_port = chromite_serial_release_port,
+ .request_port = chromite_serial_request_port,
+ .config_port = chromite_serial_config_port,
+ .verify_port = chromite_serial_verify_port,
+#ifdef CONFIG_CONSOLE_POLL
+ .poll_get_char = chromite_serial_poll_get_char,
+ .poll_put_char = chromite_serial_poll_put_char,
+#endif
+};
+
+
+static struct uart_driver chromite_serial_uart_driver = {
+ .owner = THIS_MODULE,
+ .driver_name = "chromite-serial",
+ .dev_name = CHROMITE_TTY_PREFIX,
+ .nr = 1,
+ .cons = CHROMITE_SERIAL_CONSOLE,
+};
+
+static int chromite_serial_probe(struct platform_device *pdev)
+{
+ struct chromite_serial_port *csp;
+ struct resource *mem;
+ void __iomem *base;
+ int irq, id, r;
+ u32 cr;
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0)
+ return -EPROBE_DEFER;
+
+ mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ base = devm_ioremap_resource(&pdev->dev, mem);
+ if (IS_ERR(base)) {
+ dev_err(&pdev->dev, "could not acquire device memory\n");
+ return PTR_ERR(base);
+ }
+ id = of_alias_get_id(pdev->dev.of_node, "serial");
+ if (id < 0) {
+ dev_err(&pdev->dev, "missing aliases entry\n");
+ return id;
+ }
+#ifdef CONFIG_SERIAL_CHROMITE_CONSOLE
+ if (id > CHROMITE_SERIAL_MAX_PORTS) {
+ dev_err(&pdev->dev, "too many UARTs (%d)\n", id);
+ return -EINVAL;
+ }
+#endif /* CONFIG_SERIAL_CHROMITE_CONSOLE */
+
+ csp = devm_kzalloc(&pdev->dev, sizeof(*csp), GFP_KERNEL);
+ if (!csp)
+ return -ENOMEM;
+
+ csp->port.dev = &pdev->dev;
+ csp->port.type = PORT_CHROMITE;
+ csp->port.iotype = UPIO_MEM;
+ csp->port.irq = irq;
+ csp->port.fifosize = TX_FIFO_DEPTH;
+ csp->port.ops = &chromite_serial_uart_ops;
+ csp->port.line = id;
+ csp->port.mapbase = mem->start;
+ csp->port.membase = base;
+ csp->dev = &pdev->dev;
+
+ /* Set up clock divider */
+ csp->clkin_rate = CHROMITE_CLOCK;
+ csp->baud_rate = CHROMITE_DEFAULT_BAUD_RATE;
+ csp->port.uartclk = csp->baud_rate * 16;
+ chromite_serial_update_div(csp);
+
+ csp->cread_flag = 1;
+
+ platform_set_drvdata(pdev, csp);
+
+ cr = readl_relaxed(csp->port.membase + CONTROL_REG_OFF);
+ /* Set TX_THLD_AUTO_RST and RX_THLD_AUTO_RST in control register to 1 */
+ cr |= (1 << CONTROL_REG_TX_THLD_AUTO_RST_SHIFT) |
+ (1 << CONTROL_REG_RX_THLD_AUTO_RST_SHIFT);
+ /* Set TX_THLD and RX_THLD in control register to 0 */
+ cr &= ~(CONTROL_REG_TX_THLD_MASK | CONTROL_REG_RX_THLD_MASK);
+ writel_relaxed(cr, csp->port.membase + CONTROL_REG_OFF);
+
+ r = request_irq(csp->port.irq, chromite_serial_irq, csp->port.irqflags,
+ dev_name(&pdev->dev), csp);
+ if (r) {
+ dev_err(&pdev->dev, "could not attach interrupt: %d\n", r);
+ goto probe_out1;
+ }
+
+ chromite_add_console_port(csp);
+
+ r = uart_add_one_port(&chromite_serial_uart_driver, &csp->port);
+ if (r != 0) {
+ dev_err(&pdev->dev, "could not add uart: %d\n", r);
+ goto probe_out2;
+ }
+
+ return 0;
+
+probe_out2:
+ chromite_remove_console_port(csp);
+ free_irq(csp->port.irq, csp);
+probe_out1:
+ return r;
+}
+
+static int chromite_serial_remove(struct platform_device *dev)
+{
+ struct chromite_serial_port *csp = platform_get_drvdata(dev);
+
+ chromite_remove_console_port(csp);
+ uart_remove_one_port(&chromite_serial_uart_driver, &csp->port);
+ free_irq(csp->port.irq, csp);
+
+ return 0;
+}
+
+
+static const struct of_device_id chromite_serial_of_match[] = {
+ { .compatible = "chromite,uart0" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, chromite_serial_of_match);
+
+static struct platform_driver chromite_serial_platform_driver = {
+ .probe = chromite_serial_probe,
+ .remove = chromite_serial_remove,
+ .driver = {
+ .name = "chromite-serial",
+ .of_match_table = of_match_ptr(chromite_serial_of_match),
+ },
+};
+
+static int __init chromite_serial_init(void)
+{
+ int ret = uart_register_driver(&chromite_serial_uart_driver);
+
+ if (ret)
+ return ret;
+
+ ret = platform_driver_register(&chromite_serial_platform_driver);
+ if (ret)
+ uart_unregister_driver(&chromite_serial_uart_driver);
+
+ return ret;
+}
+
+static void __exit chromite_serial_exit(void)
+{
+ platform_driver_unregister(&chromite_serial_platform_driver);
+ uart_unregister_driver(&chromite_serial_uart_driver);
+}
+
+module_init(chromite_serial_init);
+module_exit(chromite_serial_exit);
+
+MODULE_DESCRIPTION("Chromite UART serial driver");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Sathish Kumar Balasubrananiam <b-sathishkumar@xxxxxxx>");
+
diff --git a/include/uapi/linux/serial_core.h b/include/uapi/linux/serial_core.h
index c4042dcfdc0c..91592471e762 100644
--- a/include/uapi/linux/serial_core.h
+++ b/include/uapi/linux/serial_core.h
@@ -274,4 +274,7 @@
/* Freescale LINFlexD UART */
#define PORT_LINFLEXUART 122
+/* Chromite UART */
+#define PORT_CHROMITE 123
+
#endif /* _UAPILINUX_SERIAL_CORE_H */
--
2.17.1
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