summaryrefslogtreecommitdiffstats
path: root/drivers/tty/serial/21285.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/tty/serial/21285.c')
-rw-r--r--drivers/tty/serial/21285.c539
1 files changed, 539 insertions, 0 deletions
diff --git a/drivers/tty/serial/21285.c b/drivers/tty/serial/21285.c
new file mode 100644
index 000000000..c7d34823f
--- /dev/null
+++ b/drivers/tty/serial/21285.c
@@ -0,0 +1,539 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for the serial port on the 21285 StrongArm-110 core logic chip.
+ *
+ * Based on drivers/char/serial.c
+ */
+#include <linux/module.h>
+#include <linux/tty.h>
+#include <linux/ioport.h>
+#include <linux/init.h>
+#include <linux/console.h>
+#include <linux/device.h>
+#include <linux/tty_flip.h>
+#include <linux/serial_core.h>
+#include <linux/serial.h>
+#include <linux/io.h>
+
+#include <asm/irq.h>
+#include <asm/mach-types.h>
+#include <asm/system_info.h>
+#include <asm/hardware/dec21285.h>
+#include <mach/hardware.h>
+
+#define BAUD_BASE (mem_fclk_21285/64)
+
+#define SERIAL_21285_NAME "ttyFB"
+#define SERIAL_21285_MAJOR 204
+#define SERIAL_21285_MINOR 4
+
+#define RXSTAT_DUMMY_READ 0x80000000
+#define RXSTAT_FRAME (1 << 0)
+#define RXSTAT_PARITY (1 << 1)
+#define RXSTAT_OVERRUN (1 << 2)
+#define RXSTAT_ANYERR (RXSTAT_FRAME|RXSTAT_PARITY|RXSTAT_OVERRUN)
+
+#define H_UBRLCR_BREAK (1 << 0)
+#define H_UBRLCR_PARENB (1 << 1)
+#define H_UBRLCR_PAREVN (1 << 2)
+#define H_UBRLCR_STOPB (1 << 3)
+#define H_UBRLCR_FIFO (1 << 4)
+
+static const char serial21285_name[] = "Footbridge UART";
+
+/*
+ * We only need 2 bits of data, so instead of creating a whole structure for
+ * this, use bits of the private_data pointer of the uart port structure.
+ */
+#define tx_enabled_bit 0
+#define rx_enabled_bit 1
+
+static bool is_enabled(struct uart_port *port, int bit)
+{
+ unsigned long *private_data = (unsigned long *)&port->private_data;
+
+ if (test_bit(bit, private_data))
+ return true;
+ return false;
+}
+
+static void enable(struct uart_port *port, int bit)
+{
+ unsigned long *private_data = (unsigned long *)&port->private_data;
+
+ set_bit(bit, private_data);
+}
+
+static void disable(struct uart_port *port, int bit)
+{
+ unsigned long *private_data = (unsigned long *)&port->private_data;
+
+ clear_bit(bit, private_data);
+}
+
+#define is_tx_enabled(port) is_enabled(port, tx_enabled_bit)
+#define tx_enable(port) enable(port, tx_enabled_bit)
+#define tx_disable(port) disable(port, tx_enabled_bit)
+
+#define is_rx_enabled(port) is_enabled(port, rx_enabled_bit)
+#define rx_enable(port) enable(port, rx_enabled_bit)
+#define rx_disable(port) disable(port, rx_enabled_bit)
+
+/*
+ * The documented expression for selecting the divisor is:
+ * BAUD_BASE / baud - 1
+ * However, typically BAUD_BASE is not divisible by baud, so
+ * we want to select the divisor that gives us the minimum
+ * error. Therefore, we want:
+ * int(BAUD_BASE / baud - 0.5) ->
+ * int(BAUD_BASE / baud - (baud >> 1) / baud) ->
+ * int((BAUD_BASE - (baud >> 1)) / baud)
+ */
+
+static void serial21285_stop_tx(struct uart_port *port)
+{
+ if (is_tx_enabled(port)) {
+ disable_irq_nosync(IRQ_CONTX);
+ tx_disable(port);
+ }
+}
+
+static void serial21285_start_tx(struct uart_port *port)
+{
+ if (!is_tx_enabled(port)) {
+ enable_irq(IRQ_CONTX);
+ tx_enable(port);
+ }
+}
+
+static void serial21285_stop_rx(struct uart_port *port)
+{
+ if (is_rx_enabled(port)) {
+ disable_irq_nosync(IRQ_CONRX);
+ rx_disable(port);
+ }
+}
+
+static irqreturn_t serial21285_rx_chars(int irq, void *dev_id)
+{
+ struct uart_port *port = dev_id;
+ unsigned int status, ch, flag, rxs, max_count = 256;
+
+ status = *CSR_UARTFLG;
+ while (!(status & 0x10) && max_count--) {
+ ch = *CSR_UARTDR;
+ flag = TTY_NORMAL;
+ port->icount.rx++;
+
+ rxs = *CSR_RXSTAT | RXSTAT_DUMMY_READ;
+ if (unlikely(rxs & RXSTAT_ANYERR)) {
+ if (rxs & RXSTAT_PARITY)
+ port->icount.parity++;
+ else if (rxs & RXSTAT_FRAME)
+ port->icount.frame++;
+ if (rxs & RXSTAT_OVERRUN)
+ port->icount.overrun++;
+
+ rxs &= port->read_status_mask;
+
+ if (rxs & RXSTAT_PARITY)
+ flag = TTY_PARITY;
+ else if (rxs & RXSTAT_FRAME)
+ flag = TTY_FRAME;
+ }
+
+ uart_insert_char(port, rxs, RXSTAT_OVERRUN, ch, flag);
+
+ status = *CSR_UARTFLG;
+ }
+ tty_flip_buffer_push(&port->state->port);
+
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t serial21285_tx_chars(int irq, void *dev_id)
+{
+ struct uart_port *port = dev_id;
+ struct circ_buf *xmit = &port->state->xmit;
+ int count = 256;
+
+ if (port->x_char) {
+ *CSR_UARTDR = port->x_char;
+ port->icount.tx++;
+ port->x_char = 0;
+ goto out;
+ }
+ if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
+ serial21285_stop_tx(port);
+ goto out;
+ }
+
+ do {
+ *CSR_UARTDR = xmit->buf[xmit->tail];
+ xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+ port->icount.tx++;
+ if (uart_circ_empty(xmit))
+ break;
+ } while (--count > 0 && !(*CSR_UARTFLG & 0x20));
+
+ if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+ uart_write_wakeup(port);
+
+ if (uart_circ_empty(xmit))
+ serial21285_stop_tx(port);
+
+ out:
+ return IRQ_HANDLED;
+}
+
+static unsigned int serial21285_tx_empty(struct uart_port *port)
+{
+ return (*CSR_UARTFLG & 8) ? 0 : TIOCSER_TEMT;
+}
+
+/* no modem control lines */
+static unsigned int serial21285_get_mctrl(struct uart_port *port)
+{
+ return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
+}
+
+static void serial21285_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+}
+
+static void serial21285_break_ctl(struct uart_port *port, int break_state)
+{
+ unsigned long flags;
+ unsigned int h_lcr;
+
+ spin_lock_irqsave(&port->lock, flags);
+ h_lcr = *CSR_H_UBRLCR;
+ if (break_state)
+ h_lcr |= H_UBRLCR_BREAK;
+ else
+ h_lcr &= ~H_UBRLCR_BREAK;
+ *CSR_H_UBRLCR = h_lcr;
+ spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static int serial21285_startup(struct uart_port *port)
+{
+ int ret;
+
+ tx_enable(port);
+ rx_enable(port);
+
+ ret = request_irq(IRQ_CONRX, serial21285_rx_chars, 0,
+ serial21285_name, port);
+ if (ret == 0) {
+ ret = request_irq(IRQ_CONTX, serial21285_tx_chars, 0,
+ serial21285_name, port);
+ if (ret)
+ free_irq(IRQ_CONRX, port);
+ }
+
+ return ret;
+}
+
+static void serial21285_shutdown(struct uart_port *port)
+{
+ free_irq(IRQ_CONTX, port);
+ free_irq(IRQ_CONRX, port);
+}
+
+static void
+serial21285_set_termios(struct uart_port *port, struct ktermios *termios,
+ const struct ktermios *old)
+{
+ unsigned long flags;
+ unsigned int baud, quot, h_lcr, b;
+
+ /*
+ * We don't support modem control lines.
+ */
+ termios->c_cflag &= ~(HUPCL | CRTSCTS | CMSPAR);
+ termios->c_cflag |= CLOCAL;
+
+ /*
+ * We don't support BREAK character recognition.
+ */
+ termios->c_iflag &= ~(IGNBRK | BRKINT);
+
+ /*
+ * Ask the core to calculate the divisor for us.
+ */
+ baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16);
+ quot = uart_get_divisor(port, baud);
+ b = port->uartclk / (16 * quot);
+ tty_termios_encode_baud_rate(termios, b, b);
+
+ switch (termios->c_cflag & CSIZE) {
+ case CS5:
+ h_lcr = 0x00;
+ break;
+ case CS6:
+ h_lcr = 0x20;
+ break;
+ case CS7:
+ h_lcr = 0x40;
+ break;
+ default: /* CS8 */
+ h_lcr = 0x60;
+ break;
+ }
+
+ if (termios->c_cflag & CSTOPB)
+ h_lcr |= H_UBRLCR_STOPB;
+ if (termios->c_cflag & PARENB) {
+ h_lcr |= H_UBRLCR_PARENB;
+ if (!(termios->c_cflag & PARODD))
+ h_lcr |= H_UBRLCR_PAREVN;
+ }
+
+ if (port->fifosize)
+ h_lcr |= H_UBRLCR_FIFO;
+
+ spin_lock_irqsave(&port->lock, flags);
+
+ /*
+ * Update the per-port timeout.
+ */
+ uart_update_timeout(port, termios->c_cflag, baud);
+
+ /*
+ * Which character status flags are we interested in?
+ */
+ port->read_status_mask = RXSTAT_OVERRUN;
+ if (termios->c_iflag & INPCK)
+ port->read_status_mask |= RXSTAT_FRAME | RXSTAT_PARITY;
+
+ /*
+ * Which character status flags should we ignore?
+ */
+ port->ignore_status_mask = 0;
+ if (termios->c_iflag & IGNPAR)
+ port->ignore_status_mask |= RXSTAT_FRAME | RXSTAT_PARITY;
+ if (termios->c_iflag & IGNBRK && termios->c_iflag & IGNPAR)
+ port->ignore_status_mask |= RXSTAT_OVERRUN;
+
+ /*
+ * Ignore all characters if CREAD is not set.
+ */
+ if ((termios->c_cflag & CREAD) == 0)
+ port->ignore_status_mask |= RXSTAT_DUMMY_READ;
+
+ quot -= 1;
+
+ *CSR_UARTCON = 0;
+ *CSR_L_UBRLCR = quot & 0xff;
+ *CSR_M_UBRLCR = (quot >> 8) & 0x0f;
+ *CSR_H_UBRLCR = h_lcr;
+ *CSR_UARTCON = 1;
+
+ spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static const char *serial21285_type(struct uart_port *port)
+{
+ return port->type == PORT_21285 ? "DC21285" : NULL;
+}
+
+static void serial21285_release_port(struct uart_port *port)
+{
+ release_mem_region(port->mapbase, 32);
+}
+
+static int serial21285_request_port(struct uart_port *port)
+{
+ return request_mem_region(port->mapbase, 32, serial21285_name)
+ != NULL ? 0 : -EBUSY;
+}
+
+static void serial21285_config_port(struct uart_port *port, int flags)
+{
+ if (flags & UART_CONFIG_TYPE && serial21285_request_port(port) == 0)
+ port->type = PORT_21285;
+}
+
+/*
+ * verify the new serial_struct (for TIOCSSERIAL).
+ */
+static int serial21285_verify_port(struct uart_port *port, struct serial_struct *ser)
+{
+ int ret = 0;
+ if (ser->type != PORT_UNKNOWN && ser->type != PORT_21285)
+ ret = -EINVAL;
+ if (ser->irq <= 0)
+ ret = -EINVAL;
+ if (ser->baud_base != port->uartclk / 16)
+ ret = -EINVAL;
+ return ret;
+}
+
+static const struct uart_ops serial21285_ops = {
+ .tx_empty = serial21285_tx_empty,
+ .get_mctrl = serial21285_get_mctrl,
+ .set_mctrl = serial21285_set_mctrl,
+ .stop_tx = serial21285_stop_tx,
+ .start_tx = serial21285_start_tx,
+ .stop_rx = serial21285_stop_rx,
+ .break_ctl = serial21285_break_ctl,
+ .startup = serial21285_startup,
+ .shutdown = serial21285_shutdown,
+ .set_termios = serial21285_set_termios,
+ .type = serial21285_type,
+ .release_port = serial21285_release_port,
+ .request_port = serial21285_request_port,
+ .config_port = serial21285_config_port,
+ .verify_port = serial21285_verify_port,
+};
+
+static struct uart_port serial21285_port = {
+ .mapbase = 0x42000160,
+ .iotype = UPIO_MEM,
+ .irq = 0,
+ .fifosize = 16,
+ .ops = &serial21285_ops,
+ .flags = UPF_BOOT_AUTOCONF,
+};
+
+static void serial21285_setup_ports(void)
+{
+ serial21285_port.uartclk = mem_fclk_21285 / 4;
+}
+
+#ifdef CONFIG_SERIAL_21285_CONSOLE
+static void serial21285_console_putchar(struct uart_port *port, unsigned char ch)
+{
+ while (*CSR_UARTFLG & 0x20)
+ barrier();
+ *CSR_UARTDR = ch;
+}
+
+static void
+serial21285_console_write(struct console *co, const char *s,
+ unsigned int count)
+{
+ uart_console_write(&serial21285_port, s, count, serial21285_console_putchar);
+}
+
+static void __init
+serial21285_get_options(struct uart_port *port, int *baud,
+ int *parity, int *bits)
+{
+ if (*CSR_UARTCON == 1) {
+ unsigned int tmp;
+
+ tmp = *CSR_H_UBRLCR;
+ switch (tmp & 0x60) {
+ case 0x00:
+ *bits = 5;
+ break;
+ case 0x20:
+ *bits = 6;
+ break;
+ case 0x40:
+ *bits = 7;
+ break;
+ default:
+ case 0x60:
+ *bits = 8;
+ break;
+ }
+
+ if (tmp & H_UBRLCR_PARENB) {
+ *parity = 'o';
+ if (tmp & H_UBRLCR_PAREVN)
+ *parity = 'e';
+ }
+
+ tmp = *CSR_L_UBRLCR | (*CSR_M_UBRLCR << 8);
+
+ *baud = port->uartclk / (16 * (tmp + 1));
+ }
+}
+
+static int __init serial21285_console_setup(struct console *co, char *options)
+{
+ struct uart_port *port = &serial21285_port;
+ int baud = 9600;
+ int bits = 8;
+ int parity = 'n';
+ int flow = 'n';
+
+ /*
+ * Check whether an invalid uart number has been specified, and
+ * if so, search for the first available port that does have
+ * console support.
+ */
+ if (options)
+ uart_parse_options(options, &baud, &parity, &bits, &flow);
+ else
+ serial21285_get_options(port, &baud, &parity, &bits);
+
+ return uart_set_options(port, co, baud, parity, bits, flow);
+}
+
+static struct uart_driver serial21285_reg;
+
+static struct console serial21285_console =
+{
+ .name = SERIAL_21285_NAME,
+ .write = serial21285_console_write,
+ .device = uart_console_device,
+ .setup = serial21285_console_setup,
+ .flags = CON_PRINTBUFFER,
+ .index = -1,
+ .data = &serial21285_reg,
+};
+
+static int __init rs285_console_init(void)
+{
+ serial21285_setup_ports();
+ register_console(&serial21285_console);
+ return 0;
+}
+console_initcall(rs285_console_init);
+
+#define SERIAL_21285_CONSOLE &serial21285_console
+#else
+#define SERIAL_21285_CONSOLE NULL
+#endif
+
+static struct uart_driver serial21285_reg = {
+ .owner = THIS_MODULE,
+ .driver_name = "ttyFB",
+ .dev_name = "ttyFB",
+ .major = SERIAL_21285_MAJOR,
+ .minor = SERIAL_21285_MINOR,
+ .nr = 1,
+ .cons = SERIAL_21285_CONSOLE,
+};
+
+static int __init serial21285_init(void)
+{
+ int ret;
+
+ printk(KERN_INFO "Serial: 21285 driver\n");
+
+ serial21285_setup_ports();
+
+ ret = uart_register_driver(&serial21285_reg);
+ if (ret == 0)
+ uart_add_one_port(&serial21285_reg, &serial21285_port);
+
+ return ret;
+}
+
+static void __exit serial21285_exit(void)
+{
+ uart_remove_one_port(&serial21285_reg, &serial21285_port);
+ uart_unregister_driver(&serial21285_reg);
+}
+
+module_init(serial21285_init);
+module_exit(serial21285_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Intel Footbridge (21285) serial driver");
+MODULE_ALIAS_CHARDEV(SERIAL_21285_MAJOR, SERIAL_21285_MINOR);
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-24 03:39:04 +0000