Hi Peter, thanks for the review and the useful comments. I will incorporate your comments in the next version. ... On 02/09/14 19:19, Peter Hurley wrote: > Hi Andre, > > On 08/29/2014 12:13 PM, Andre Przywara wrote: >> The ARM Server Base System Architecture (SBSA) describes a generic >> UART which all compliant level 1 systems should implement. This is >> actually a PL011 subset, so a full PL011 implementation will satisfy >> this requirement. >> However if a system does not have a PL011, a very stripped down >> implementation complying to the SBSA defined specification will >> suffice. The Linux PL011 driver is not guaranteed to drive this >> limited device (and indeed the fast model implentation hangs the >> kernel if driven by the PL011 driver). >> So introduce a new driver just implementing the part specified by the >> SBSA (which lacks DMA, the modem control signals and many of the >> registers including baud rate control). This driver has been derived >> by the actual PL011 one, removing all unnecessary code. >> >> Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx> >> --- >> .../devicetree/bindings/serial/arm_sbsa_uart.txt | 6 + >> drivers/tty/serial/Kconfig | 28 + >> drivers/tty/serial/Makefile | 1 + >> drivers/tty/serial/sbsa_uart.c | 793 ++++++++++++++++++++ >> include/uapi/linux/serial_core.h | 1 + >> 5 files changed, 829 insertions(+) >> create mode 100644 Documentation/devicetree/bindings/serial/arm_sbsa_uart.txt >> create mode 100644 drivers/tty/serial/sbsa_uart.c >> >> diff --git a/Documentation/devicetree/bindings/serial/arm_sbsa_uart.txt b/Documentation/devicetree/bindings/serial/arm_sbsa_uart.txt >> new file mode 100644 >> index 0000000..8e2c5d6 >> --- /dev/null >> +++ b/Documentation/devicetree/bindings/serial/arm_sbsa_uart.txt >> @@ -0,0 +1,6 @@ >> +* ARM SBSA defined generic UART >> + >> +Required properties: >> +- compatible: must be "arm,sbsa-uart" >> +- reg: exactly one register range >> +- interrupts: exactly one interrupt specifier >> diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig >> index 26cec64..faecfad 100644 >> --- a/drivers/tty/serial/Kconfig >> +++ b/drivers/tty/serial/Kconfig >> @@ -45,6 +45,34 @@ config SERIAL_AMBA_PL010_CONSOLE >> your boot loader (lilo or loadlin) about how to pass options to the >> kernel at boot time.) >> >> +config SERIAL_SBSA_UART >> + tristate "ARM SBSA UART serial port support" >> + select SERIAL_CORE >> + help >> + This selects the UART defined in the ARM(R) Server Base System >> + Architecture (SBSA). >> + It is a true subset of the ARM(R) PL011 UART and this driver can >> + also drive those full featured UARTs. >> + To match the SBSA, this driver will not support initialization, DMA, >> + baudrate control and modem control lines. >> + >> +config SERIAL_SBSA_UART_CONSOLE >> + bool "Support for console on ARM SBSA UART serial port" >> + depends on SERIAL_SBSA_UART=y >> + select SERIAL_CORE_CONSOLE >> + select SERIAL_EARLYCON >> + ---help--- >> + Say Y here if you wish to use an ARM SBSA UART as the system >> + console (the system console is the device which receives all kernel >> + messages and warnings and which allows logins in single user mode). >> + >> + Even if you say Y here, the currently visible framebuffer 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=ttyAMA0". (Try "man bootparam" or see the documentation of >> + your boot loader (lilo or loadlin) about how to pass options to the >> + kernel at boot time.) >> + >> config SERIAL_AMBA_PL011 >> tristate "ARM AMBA PL011 serial port support" >> depends on ARM_AMBA >> diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile >> index 0080cc3..2e560e9 100644 >> --- a/drivers/tty/serial/Makefile >> +++ b/drivers/tty/serial/Makefile >> @@ -22,6 +22,7 @@ obj-$(CONFIG_SERIAL_8250) += 8250/ >> >> obj-$(CONFIG_SERIAL_AMBA_PL010) += amba-pl010.o >> obj-$(CONFIG_SERIAL_AMBA_PL011) += amba-pl011.o >> +obj-$(CONFIG_SERIAL_SBSA_UART) += sbsa_uart.o >> obj-$(CONFIG_SERIAL_CLPS711X) += clps711x.o >> obj-$(CONFIG_SERIAL_PXA) += pxa.o >> obj-$(CONFIG_SERIAL_PNX8XXX) += pnx8xxx_uart.o >> diff --git a/drivers/tty/serial/sbsa_uart.c b/drivers/tty/serial/sbsa_uart.c >> new file mode 100644 >> index 0000000..941a305 >> --- /dev/null >> +++ b/drivers/tty/serial/sbsa_uart.c >> @@ -0,0 +1,793 @@ >> +/* >> + * Driver for ARM SBSA specified serial ports (stripped down PL011) >> + * >> + * Based on drivers/tty/char/amba-pl011.c >> + * >> + * Copyright 2014 ARM Limited >> + * >> + * 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. >> + * >> + * You should have received a copy of the GNU General Public License >> + * along with this program. If not, see <http://www.gnu.org/licenses/>. >> + * >> + * This is a driver implementing the ARM SBSA specified generic UART, >> + * which is a subset of the PL011 UART, but lacking: >> + * - DMA >> + * - hardware flow control >> + * - modem control >> + * - IrDA SIR >> + * - word lengths other than 8 bits >> + * - baudrate settings >> + */ >> + >> + >> +#if defined(CONFIG_SERIAL_SBSA_UART_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) >> +#define SUPPORT_SYSRQ >> +#endif >> + >> +#include <linux/module.h> >> +#include <linux/init.h> >> +#include <linux/console.h> >> +#include <linux/sysrq.h> >> +#include <linux/device.h> >> +#include <linux/tty.h> >> +#include <linux/tty_flip.h> >> +#include <linux/serial_core.h> >> +#include <linux/serial.h> >> +#include <linux/amba/serial.h> >> +#include <linux/slab.h> >> +#include <linux/types.h> >> +#include <linux/of.h> >> +#include <linux/of_device.h> >> +#include <linux/sizes.h> >> +#include <linux/io.h> >> + >> +#define UART_NR 14 >> + >> +#define UART_DR_ERROR (UART011_DR_OE|UART011_DR_BE|UART011_DR_PE|UART011_DR_FE) >> +#define UART_DUMMY_DR_RX (1 << 16) >> + >> +/* >> + * Reads up to 256 characters from the FIFO or until it's empty and >> + * inserts them into the TTY layer. Returns the number of characters >> + * read from the FIFO. >> + */ >> +static int sbsa_uart_fifo_to_tty(struct uart_port *port) >> +{ >> + u16 status, ch; >> + unsigned int flag, max_count = 256; >> + int fifotaken = 0; >> + >> + while (max_count--) { >> + status = readw(port->membase + UART01x_FR); >> + if (status & UART01x_FR_RXFE) >> + break; >> + >> + /* Take chars from the FIFO and update status */ >> + ch = readw(port->membase + UART01x_DR) | UART_DUMMY_DR_RX; >> + flag = TTY_NORMAL; >> + port->icount.rx++; >> + fifotaken++; >> + >> + if (unlikely(ch & UART_DR_ERROR)) { >> + if (ch & UART011_DR_BE) { >> + ch &= ~(UART011_DR_FE | UART011_DR_PE); >> + port->icount.brk++; >> + if (uart_handle_break(port)) >> + continue; >> + } else if (ch & UART011_DR_PE) >> + port->icount.parity++; >> + else if (ch & UART011_DR_FE) >> + port->icount.frame++; >> + if (ch & UART011_DR_OE) >> + port->icount.overrun++; >> + >> + ch &= port->read_status_mask; >> + >> + if (ch & UART011_DR_BE) >> + flag = TTY_BREAK; >> + else if (ch & UART011_DR_PE) >> + flag = TTY_PARITY; >> + else if (ch & UART011_DR_FE) >> + flag = TTY_FRAME; >> + } >> + >> + if (uart_handle_sysrq_char(port, ch & 255)) >> + continue; >> + >> + uart_insert_char(port, ch, UART011_DR_OE, ch, flag); >> + } >> + >> + return fifotaken; >> +} >> + >> +static void sbsa_uart_mask_irq(struct uart_port *port, u16 irqclr, u16 irqset) >> +{ >> + u16 imsc; >> + >> + imsc = readw(port->membase + UART011_IMSC); >> + imsc = (imsc & ~irqclr) | irqset; >> + writew(imsc, port->membase + UART011_IMSC); >> +} >> + >> +static void sbsa_uart_stop_tx(struct uart_port *port) >> +{ >> + sbsa_uart_mask_irq(port, UART011_TXIM, 0); >> +} >> + >> +static void sbsa_uart_start_tx(struct uart_port *port) >> +{ >> + sbsa_uart_mask_irq(port, 0, UART011_TXIM); >> +} >> + >> +static void sbsa_uart_stop_rx(struct uart_port *port) >> +{ >> + sbsa_uart_mask_irq(port, UART011_RXIM | UART011_RTIM, 0); >> +} >> + >> +static void sbsa_uart_rx_chars(struct uart_port *port) >> +__releases(&uap->port.lock) >> +__acquires(&uap->port.lock) > ^^^^^^^^^^ > I think sparse will choke here. > > >> +{ >> + sbsa_uart_fifo_to_tty(port); >> + >> + spin_unlock(&port->lock); >> + tty_flip_buffer_push(&port->state->port); >> + spin_lock(&port->lock); >> +} >> + >> +static void sbsa_uart_tx_chars(struct uart_port *port) >> +{ >> + struct circ_buf *xmit = &port->state->xmit; >> + int count; >> + >> + if (port->x_char) { >> + writew(port->x_char, port->membase + UART01x_DR); >> + port->icount.tx++; >> + port->x_char = 0; >> + return; >> + } >> + if (uart_circ_empty(xmit) || uart_tx_stopped(port)) { >> + sbsa_uart_stop_tx(port); >> + return; >> + } >> + >> + count = port->fifosize >> 1; >> + do { >> + writew(xmit->buf[xmit->tail], port->membase + UART01x_DR); >> + xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); >> + port->icount.tx++; >> + if (uart_circ_empty(xmit)) >> + break; >> + } while (--count > 0); >> + >> + if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) >> + uart_write_wakeup(port); >> + >> + if (uart_circ_empty(xmit)) >> + sbsa_uart_stop_tx(port); >> +} >> + >> +static irqreturn_t sbsa_uart_int(int irq, void *dev_id) >> +{ >> + struct uart_port *port = dev_id; >> + unsigned long flags; >> + unsigned int status, pass_counter = 32; >> + int handled = 0; >> + >> + spin_lock_irqsave(&port->lock, flags); >> + status = readw(port->membase + UART011_RIS); >> + status &= readw(port->membase + UART011_IMSC); >> + if (status) { >> + do { >> + writew(status & ~(UART011_TXIS|UART011_RTIS| >> + UART011_RXIS), >> + port->membase + UART011_ICR); >> + >> + if (status & (UART011_RTIS|UART011_RXIS)) >> + sbsa_uart_rx_chars(port); >> + >> + if (status & UART011_TXIS) >> + sbsa_uart_tx_chars(port); >> + >> + if (pass_counter-- == 0) >> + break; >> + >> + status = readw(port->membase + UART011_RIS); >> + status &= ~readw(port->membase + UART011_IMSC); >> + } while (status != 0); >> + handled = 1; >> + } >> + >> + spin_unlock_irqrestore(&port->lock, flags); >> + >> + return IRQ_RETVAL(handled); >> +} >> + >> +static unsigned int sbsa_uart_tx_empty(struct uart_port *port) >> +{ >> + unsigned int status = readw(port->membase + UART01x_FR); >> + >> + return status & (UART01x_FR_BUSY|UART01x_FR_TXFF) ? 0 : TIOCSER_TEMT; >> +} >> + >> +static unsigned int sbsa_uart_get_mctrl(struct uart_port *port) >> +{ >> + return 0; >> +} >> + >> +static void sbsa_uart_set_mctrl(struct uart_port *port, unsigned int mctrl) >> +{ >> +} >> + >> +#ifdef CONFIG_CONSOLE_POLL >> + >> +static void sbsa_uart_quiesce_irqs(struct uart_port *port) >> +{ >> + writew(readw(port->membase + UART011_RIS), port->membase + UART011_ICR); >> + /* >> + * There is no way to clear TXIM as this is "ready to transmit IRQ", so >> + * we simply mask it. start_tx() will unmask it. >> + * >> + * Note we can race with start_tx(), and if the race happens, the >> + * polling user might get another interrupt just after we clear it. >> + * But it should be OK and can happen even w/o the race, e.g. >> + * controller immediately got some new data and raised the IRQ. >> + * >> + * And whoever uses polling routines assumes that it manages the device >> + * (including tx queue), so we're also fine with start_tx()'s caller >> + * side. >> + */ >> + writew(readw(port->membase + UART011_IMSC) & ~UART011_TXIM, >> + port->membase + UART011_IMSC); >> +} >> + >> +static int sbsa_uart_get_poll_char(struct uart_port *port) >> +{ >> + unsigned int status; >> + >> + /* >> + * The caller might need IRQs lowered, e.g. if used with KDB NMI >> + * debugger. >> + */ >> + sbsa_uart_quiesce_irqs(port); >> + >> + status = readw(port->membase + UART01x_FR); >> + if (status & UART01x_FR_RXFE) >> + return NO_POLL_CHAR; >> + >> + return readw(port->membase + UART01x_DR); >> +} >> + >> +static void sbsa_uart_put_poll_char(struct uart_port *port, unsigned char ch) >> +{ >> + while (readw(port->membase + UART01x_FR) & UART01x_FR_TXFF) >> + barrier(); >> + >> + writew(ch, port->membase + UART01x_DR); >> +} >> + >> +#endif /* CONFIG_CONSOLE_POLL */ >> + >> +static int sbsa_uart_hwinit(struct uart_port *port) >> +{ >> + /* Clear pending error and receive interrupts */ >> + writew(UART011_OEIS | UART011_BEIS | UART011_PEIS | UART011_FEIS | >> + UART011_RTIS | UART011_RXIS, port->membase + UART011_ICR); >> + >> + writew(UART011_RTIM | UART011_RXIM, port->membase + UART011_IMSC); >> + >> + return 0; >> +} >> + >> +static int sbsa_uart_startup(struct uart_port *port) >> +{ >> + int retval; >> + >> + retval = sbsa_uart_hwinit(port); >> + if (retval) >> + return retval; >> + >> + /* >> + * Allocate the IRQ >> + */ >> + retval = request_irq(port->irq, sbsa_uart_int, 0, "uart-sbsa", port); >> + if (retval) >> + return retval; >> + >> + /* >> + * Provoke TX FIFO interrupt into asserting. Taking care to preserve >> + * baud rate and data format specified by FBRD, IBRD and LCRH as the >> + * UART may already be in use as a console. >> + */ >> + spin_lock_irq(&port->lock); >> + >> + /* >> + * this does not work on the SBSA UART, because it does not have >> + * a CR and thus not loopback enable bit >> + */ >> + writew(0, port->membase + UART01x_DR); >> + while (readw(port->membase + UART01x_FR) & UART01x_FR_BUSY) >> + barrier(); >> + >> + /* Clear out any spuriously appearing RX interrupts and enable them */ >> + writew(UART011_RTIS | UART011_RXIS, port->membase + UART011_ICR); >> + writew(UART011_RTIM | UART011_RXIM, port->membase + UART011_IMSC); >> + spin_unlock_irq(&port->lock); >> + >> + return 0; >> +} >> + >> +static void sbsa_uart_shutdown(struct uart_port *port) >> +{ >> + u16 im; >> + >> + /* >> + * disable all interrupts >> + */ >> + spin_lock_irq(&port->lock); >> + im = 0; >> + writew(im, port->membase + UART011_IMSC); >> + writew(0xffff, port->membase + UART011_ICR); >> + spin_unlock_irq(&port->lock); >> + >> + /* >> + * Free the interrupt >> + */ >> + free_irq(port->irq, port); >> + >> +} >> + >> +static void >> +sbsa_uart_set_termios(struct uart_port *port, struct ktermios *termios, >> + struct ktermios *old) >> +{ >> + unsigned long flags; >> + unsigned int baud = 115200; >> + >> + spin_lock_irqsave(&port->lock, flags); > ^^^^^^^^^^^^^^^^^ > > Can be spin_lock_irq(&port->lock) here. Why is this? Because this code cannot be called with interrupts already off? This would apply to the original PL011 driver also then? >> + >> + /* >> + * Update the per-port timeout. >> + */ >> + uart_update_timeout(port, termios->c_cflag, baud); >> + >> + port->read_status_mask = UART011_DR_OE | 255; >> + if (termios->c_iflag & INPCK) >> + port->read_status_mask |= UART011_DR_FE | UART011_DR_PE; >> + if (termios->c_iflag & (BRKINT | PARMRK)) > ^^^^^^^ > (IGNBRK | BRKINT | PARMRK) > >> + port->read_status_mask |= UART011_DR_BE; > > Otherwise, if IGNBRK is set, read_status_mask will mask the BRK condition > so a garbage TTY_NORMAL byte will be added by uart_insert_char(). The > pl011 driver has been fixed in -next. Ah, good hint. Saves me a rebase conflict later ;-) Thanks and Regards, Andre. > >> + >> + /* >> + * Characters to ignore >> + */ >> + port->ignore_status_mask = 0; >> + if (termios->c_iflag & IGNPAR) >> + port->ignore_status_mask |= UART011_DR_FE | UART011_DR_PE; >> + if (termios->c_iflag & IGNBRK) { >> + port->ignore_status_mask |= UART011_DR_BE; >> + /* >> + * If we're ignoring parity and break indicators, >> + * ignore overruns too (for real raw support). >> + */ >> + if (termios->c_iflag & IGNPAR) >> + port->ignore_status_mask |= UART011_DR_OE; >> + } >> + >> + /* >> + * Ignore all characters if CREAD is not set. >> + */ >> + if ((termios->c_cflag & CREAD) == 0) >> + port->ignore_status_mask |= UART_DUMMY_DR_RX; >> + >> + spin_unlock_irqrestore(&port->lock, flags); >> +} >> + >> +static const char *sbsa_uart_type(struct uart_port *port) >> +{ >> + return port->type == PORT_SBSA ? "SBSA" : NULL; >> +} >> + >> +/* >> + * Release the memory region(s) being used by 'port' >> + */ >> +static void sbsa_uart_release_port(struct uart_port *port) >> +{ >> + release_mem_region(port->mapbase, SZ_4K); >> +} >> + >> +/* >> + * Request the memory region(s) being used by 'port' >> + */ >> +static int sbsa_uart_request_port(struct uart_port *port) >> +{ >> + return request_mem_region(port->mapbase, SZ_4K, "uart-sbsa") >> + != NULL ? 0 : -EBUSY; >> +} >> + >> +/* >> + * Configure/autoconfigure the port. >> + */ >> +static void sbsa_uart_config_port(struct uart_port *port, int flags) >> +{ >> + if (flags & UART_CONFIG_TYPE) { >> + port->type = PORT_SBSA; >> + sbsa_uart_request_port(port); >> + } >> +} >> + >> +/* >> + * verify the new serial_struct (for TIOCSSERIAL). >> + */ >> +static int sbsa_uart_verify_port(struct uart_port *port, >> + struct serial_struct *ser) >> +{ >> + int ret = 0; >> + >> + if (ser->type != PORT_UNKNOWN && ser->type != PORT_SBSA) >> + ret = -EINVAL; >> + if (ser->irq < 0 || ser->irq >= nr_irqs) >> + ret = -EINVAL; >> + return ret; >> +} >> + >> +static struct uart_ops sbsa_uart_pops = { >> + .tx_empty = sbsa_uart_tx_empty, >> + .set_mctrl = sbsa_uart_set_mctrl, >> + .get_mctrl = sbsa_uart_get_mctrl, >> + .stop_tx = sbsa_uart_stop_tx, >> + .start_tx = sbsa_uart_start_tx, >> + .stop_rx = sbsa_uart_stop_rx, >> + .enable_ms = NULL, >> + .break_ctl = NULL, >> + .startup = sbsa_uart_startup, >> + .shutdown = sbsa_uart_shutdown, >> + .flush_buffer = NULL, >> + .set_termios = sbsa_uart_set_termios, >> + .type = sbsa_uart_type, >> + .release_port = sbsa_uart_release_port, >> + .request_port = sbsa_uart_request_port, >> + .config_port = sbsa_uart_config_port, >> + .verify_port = sbsa_uart_verify_port, >> +#ifdef CONFIG_CONSOLE_POLL >> + .poll_init = sbsa_uart_hwinit, >> + .poll_get_char = sbsa_uart_get_poll_char, >> + .poll_put_char = sbsa_uart_put_poll_char, >> +#endif >> +}; >> + >> +static struct uart_port *sbsa_uart_ports[UART_NR]; >> + >> +#ifdef CONFIG_SERIAL_SBSA_UART_CONSOLE >> + >> +static void sbsa_uart_console_putchar(struct uart_port *port, int ch) >> +{ >> + while (readw(port->membase + UART01x_FR) & UART01x_FR_TXFF) >> + barrier(); >> + writew(ch, port->membase + UART01x_DR); >> +} >> + >> +static void >> +sbsa_uart_console_write(struct console *co, const char *s, unsigned int count) >> +{ >> + struct uart_port *port = sbsa_uart_ports[co->index]; >> + unsigned int status; >> + unsigned long flags; >> + int locked = 1; >> + >> + local_irq_save(flags); >> + if (port->sysrq) >> + locked = 0; >> + else if (oops_in_progress) >> + locked = spin_trylock(&port->lock); >> + else >> + spin_lock(&port->lock); >> + >> + uart_console_write(port, s, count, sbsa_uart_console_putchar); >> + >> + /* Finally, wait for transmitter to become empty */ >> + do { >> + status = readw(port->membase + UART01x_FR); >> + } while (status & UART01x_FR_BUSY); >> + >> + if (locked) >> + spin_unlock(&port->lock); >> + local_irq_restore(flags); >> +} >> + >> +static void __init >> +sbsa_uart_console_get_options(struct uart_port *port, int *baud, >> + int *parity, int *bits) >> +{ >> + *parity = 'n'; >> + *bits = 8; >> + *baud = 115200; >> +} >> + >> +static int __init sbsa_uart_console_setup(struct console *co, char *options) >> +{ >> + struct uart_port *port; >> + int baud = 38400; >> + 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 (co->index >= UART_NR) >> + co->index = 0; >> + port = sbsa_uart_ports[co->index]; >> + if (!port) >> + return -ENODEV; >> + >> + if (options) >> + uart_parse_options(options, &baud, &parity, &bits, &flow); >> + else >> + sbsa_uart_console_get_options(port, &baud, &parity, &bits); >> + >> + return uart_set_options(port, co, baud, parity, bits, flow); >> +} >> + >> +static struct uart_driver sbsa_uart_reg; >> +static struct console sbsa_uart_console = { >> + .name = "ttyAMA", >> + .write = sbsa_uart_console_write, >> + .device = uart_console_device, >> + .setup = sbsa_uart_console_setup, >> + .flags = CON_PRINTBUFFER, >> + .index = -1, >> + .data = &sbsa_uart_reg, >> +}; >> + >> +#define SBSA_UART_CONSOLE (&sbsa_uart_console) >> + >> +static void sbsa_uart_putc(struct uart_port *port, int c) >> +{ >> + while (readw(port->membase + UART01x_FR) & UART01x_FR_TXFF) >> + ; >> + writew(c & 0xff, port->membase + UART01x_DR); >> + while (readw(port->membase + UART01x_FR) & UART01x_FR_BUSY) >> + ; >> +} >> + >> +static void sbsa_uart_early_write(struct console *con, const char *s, >> + unsigned n) >> +{ >> + struct earlycon_device *dev = con->data; >> + >> + uart_console_write(&dev->port, s, n, sbsa_uart_putc); >> +} >> + >> +static int __init sbsa_uart_early_console_setup(struct earlycon_device *device, >> + const char *opt) >> +{ >> + if (!device->port.membase) >> + return -ENODEV; >> + >> + device->con->write = sbsa_uart_early_write; >> + return 0; >> +} >> +EARLYCON_DECLARE(pl011, sbsa_uart_early_console_setup); >> +OF_EARLYCON_DECLARE(pl011, "arm,sbsa-uart", sbsa_uart_early_console_setup); >> + >> +#else >> +#define SBSA_UART_CONSOLE NULL >> +#endif >> + >> +static struct uart_driver sbsa_uart_reg = { >> + .owner = THIS_MODULE, >> + .driver_name = "sbsa_uart", >> + .dev_name = "ttyAMA", >> + .nr = UART_NR, >> + .cons = SBSA_UART_CONSOLE, >> +}; >> + >> +#ifdef CONFIG_OF >> + >> +static int dt_probe_serial_alias(int index, struct device *dev) >> +{ >> + struct device_node *np; >> + static bool seen_dev_with_alias; >> + static bool seen_dev_without_alias; >> + int ret = index; >> + >> + if (!IS_ENABLED(CONFIG_OF)) >> + return ret; >> + >> + np = dev->of_node; >> + if (!np) >> + return ret; >> + >> + ret = of_alias_get_id(np, "serial"); >> + if (IS_ERR_VALUE(ret)) { >> + seen_dev_without_alias = true; >> + ret = index; >> + } else { >> + seen_dev_with_alias = true; >> + if (ret >= ARRAY_SIZE(sbsa_uart_ports) || >> + sbsa_uart_ports[ret] != NULL) { >> + dev_warn(dev, "requested serial port %d not available.\n", ret); >> + ret = index; >> + } >> + } >> + >> + if (seen_dev_with_alias && seen_dev_without_alias) >> + dev_warn(dev, "aliased and non-aliased serial devices found in device tree. Serial port enumeration may be unpredictable.\n"); >> + >> + return ret; >> +} >> + >> +static const struct of_device_id arm_sbsa_match[] = { >> + { .compatible = "arm,sbsa-uart", }, >> + {}, >> +}; >> +MODULE_DEVICE_TABLE(of, arm_sbsa_match); >> + >> +#else >> + >> +static int dt_probe_serial_alias(int index, struct device *dev) >> +{ >> + static int portnr; >> + >> + return portnr++; >> +} >> + >> +#endif >> + >> +static int sbsa_uart_probe(struct platform_device *pdev) >> +{ >> + struct resource *r; >> + struct uart_port *port; >> + int i, ret; >> + >> + pr_info("DT probing for PL011-based SBSA UART\n"); >> + for (i = 0; i < ARRAY_SIZE(sbsa_uart_ports); i++) >> + if (sbsa_uart_ports[i] == NULL) >> + break; >> + >> + if (i == ARRAY_SIZE(sbsa_uart_ports)) { >> + ret = -EBUSY; >> + goto out; >> + } >> + >> + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); >> + >> + port = devm_kzalloc(&pdev->dev, sizeof(struct uart_port), GFP_KERNEL); >> + if (port == NULL) { >> + ret = -ENOMEM; >> + goto out; >> + } >> + >> + i = dt_probe_serial_alias(i, &pdev->dev); >> + >> + port->membase = devm_ioremap_resource(&pdev->dev, r); >> + if (!port->membase) { >> + ret = -ENOMEM; >> + goto out; >> + } >> + >> + port->irq = platform_get_irq(pdev, 0); >> + >> + dev_info(&pdev->dev, "found SBSA UART #%d at 0x%08llx\n", i, r->start); >> + >> + port->fifosize = 32; >> + port->dev = &pdev->dev; >> + port->mapbase = r->start; >> + port->iotype = UPIO_MEM; >> + port->ops = &sbsa_uart_pops; >> + port->flags = UPF_BOOT_AUTOCONF; >> + port->line = i; >> + >> + /* Ensure interrupts from this UART are masked and cleared */ >> + writew(0, port->membase + UART011_IMSC); >> + writew(0xffff, port->membase + UART011_ICR); >> + >> + sbsa_uart_ports[i] = port; >> + >> + platform_set_drvdata(pdev, port); >> + >> + if (!sbsa_uart_reg.state) { >> + ret = uart_register_driver(&sbsa_uart_reg); >> + if (ret < 0) { >> + pr_err("Failed to register ARM SBSA UART driver\n"); >> + return ret; >> + } >> + } >> + >> + ret = uart_add_one_port(&sbsa_uart_reg, port); >> + if (ret) { >> + sbsa_uart_ports[i] = NULL; >> + uart_unregister_driver(&sbsa_uart_reg); >> + } >> + out: >> + return ret; >> +} >> + >> +static int sbsa_uart_remove(struct platform_device *pdev) >> +{ >> + struct uart_port *port = platform_get_drvdata(pdev); >> + bool busy = false; >> + int i; >> + >> + uart_remove_one_port(&sbsa_uart_reg, port); >> + >> + for (i = 0; i < ARRAY_SIZE(sbsa_uart_ports); i++) >> + if (sbsa_uart_ports[i] == port) >> + sbsa_uart_ports[i] = NULL; >> + else if (sbsa_uart_ports[i]) >> + busy = true; >> + >> + if (!busy) >> + uart_unregister_driver(&sbsa_uart_reg); >> + return 0; >> +} >> + >> +static struct platform_driver arm_sbsa_uart_platform_driver = { >> + .probe = sbsa_uart_probe, >> + .remove = sbsa_uart_remove, >> + .driver = { >> + .name = "sbsa-uart", >> + .of_match_table = of_match_ptr(arm_sbsa_match), >> + }, >> +}; >> + >> +module_platform_driver(arm_sbsa_uart_platform_driver); >> + >> +#ifdef CONFIG_PM_SLEEP >> +static int sbsa_uart_suspend(struct device *dev) >> +{ >> + struct uart_port *port = dev_get_drvdata(dev); >> + >> + if (!port) >> + return -EINVAL; >> + >> + return uart_suspend_port(&sbsa_uart_reg, port); >> +} >> + >> +static int sbsa_uart_resume(struct device *dev) >> +{ >> + struct uart_port *port = dev_get_drvdata(dev); >> + >> + if (!port) >> + return -EINVAL; >> + >> + return uart_resume_port(&sbsa_uart_reg, port); >> +} >> + >> +static SIMPLE_DEV_PM_OPS(sbsa_uart_dev_pm_ops, sbsa_uart_suspend, >> + sbsa_uart_resume); >> + >> +#endif >> + >> +static int __init sbsa_uart_init(void) >> +{ >> + pr_info("Serial: ARM SBSA generic UART (PL011) driver\n"); >> + >> + return 0; >> +} >> + >> +static void __exit sbsa_uart_exit(void) >> +{ >> +} >> + >> +/* >> + * While this can be a module, if builtin it's most likely the console >> + * So let's leave module_exit but move module_init to an earlier place >> + */ >> +arch_initcall(sbsa_uart_init); >> +module_exit(sbsa_uart_exit); >> + >> +MODULE_AUTHOR("ARM Ltd"); >> +MODULE_DESCRIPTION("ARM SBSA generic UART serial port driver"); >> +MODULE_LICENSE("GPL"); >> diff --git a/include/uapi/linux/serial_core.h b/include/uapi/linux/serial_core.h >> index 5820269..9f9ee0c 100644 >> --- a/include/uapi/linux/serial_core.h >> +++ b/include/uapi/linux/serial_core.h >> @@ -67,6 +67,7 @@ >> #define PORT_CLPS711X 33 >> #define PORT_SA1100 34 >> #define PORT_UART00 35 >> +#define PORT_SBSA 36 >> #define PORT_21285 37 >> >> /* Sparc type numbers. */ >> > > Regards, > Peter Hurley > -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
