From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A3AC3FA372C for ; Thu, 7 Nov 2019 09:34:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4F99321D7B for ; Thu, 7 Nov 2019 09:34:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=antmicro.com header.i=@antmicro.com header.b="h792JkW4" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733222AbfKGJeF (ORCPT ); Thu, 7 Nov 2019 04:34:05 -0500 Received: from mail-io1-f66.google.com ([209.85.166.66]:33051 "EHLO mail-io1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727278AbfKGJeD (ORCPT ); Thu, 7 Nov 2019 04:34:03 -0500 Received: by mail-io1-f66.google.com with SMTP id j13so1571729ioe.0 for ; Thu, 07 Nov 2019 01:34:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=antmicro.com; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=ddi/Qylbfpp2oxofKrDUVCzp+G9XSLmFPLx6I0neCjE=; b=h792JkW4wS+F9sRz00e6rEBCaNgh5zdRZXusco5EFaVbIudMmSvqpYWSOK3nTAOAit PVem+1vuYKfyVNvPKgiJ2WIJgdpzKKWFY4EwgAk5cMosZrPfjnMHSZR0My6vhEZrKdbU DYm2QXmwB0FaY2fevtb28HMlkJi8P3uYVJZ9hDO/2CCWuHLg/FTAi0GB+Uzu23F3lDUd w3T6PmqXF+S7oQz20g09/lWN/VW6/61yXiReGvE4RiTHclC7aAng199Lp2emBFxY4rwb 2/s0OM63lHOgAJG/uUrYAtNkYlcyyQHEG8Y5oWGTxIZGVZpB276Pk+zTT0qZmX2H3oAf 96DQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=ddi/Qylbfpp2oxofKrDUVCzp+G9XSLmFPLx6I0neCjE=; b=YKnnVFnXGOHapIoHqNiaOvKz3N5iwpo6gNS5e7NJ+L8gVb7B16WzlTqwCU47ib7UmR bLe8iqCl1Vc8Htdg6QVltnyZb/J3SMez/iPCtrSvPkdn6lsNaVNQxTlILRQmY+AGc3sx mS172kB38LrodhjwJxgBu0/B+CVpp6roF3+yAQUGzAWb5osCNmi0b1T2iLIWKhiSMWme V+66YP/LcbZlcN/X1rCKCQB4CP5S823piW9e3z/rpjS9PVMsSr4faQ7nU1BQnHxaxFb8 8RQFw4S92hMf8fpBLpBobHsdF1z5GgUNSrNH0AswzwgSmuF3asHM4PgZm0SVc2vH4rKK FlZQ== X-Gm-Message-State: APjAAAUu50TA9cFOwjd5HAfIwudWzPjj3V93I17L7i7/waODNNtgi/U0 OG+yhS+PJY7kiX8N49+lxZDtb+H1xtMXfQ6sBkYxEQ== X-Google-Smtp-Source: APXvYqx1c+fH9XHcdSDx/OZj3G94jPGVRKobUSUaNqwMCxgEJ3lWsNxgyUcsDF0spunllk+DLBfXIXSntXQz/0V+t0E= X-Received: by 2002:a05:6638:11a:: with SMTP id x26mr3094319jao.47.1573119241396; Thu, 07 Nov 2019 01:34:01 -0800 (PST) MIME-Version: 1.0 References: <20191023114634.13657-0-mholenko@antmicro.com> <20191023114634.13657-4-mholenko@antmicro.com> <20191026001331.GB10810@bogus> In-Reply-To: <20191026001331.GB10810@bogus> From: Mateusz Holenko Date: Thu, 7 Nov 2019 10:33:50 +0100 Message-ID: Subject: Re: [PATCH v2 4/4] drivers/tty/serial: add LiteUART driver To: Rob Herring Cc: Mark Rutland , Greg Kroah-Hartman , Jiri Slaby , devicetree@vger.kernel.org, "open list:SERIAL DRIVERS" , Stafford Horne , Karol Gugala , Mauro Carvalho Chehab , "David S. Miller" , "Paul E. McKenney" , Filip Kokosinski , Joel Stanley , Jonathan Cameron , Maxime Ripard , Shawn Guo , Heiko Stuebner , Sam Ravnborg , Icenowy Zheng , Laurent Pinchart , linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Sender: linux-serial-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org sob., 26 pa=C5=BA 2019 o 02:13 Rob Herring napisa=C5=82(a= ): > > On Wed, Oct 23, 2019 at 11:47:23AM +0200, Mateusz Holenko wrote: > > From: Filip Kokosinski > > > > This commit adds driver for the FPGA-based LiteUART serial controller > > from LiteX SoC builder. > > > > The current implementation supports LiteUART configured > > for 32 bit data width and 8 bit CSR bus width. > > > > It does not support IRQ. > > > > Signed-off-by: Filip Kokosinski > > Signed-off-by: Mateusz Holenko > > --- > > Changes in v2: > > - used register access functions from newly introduced litex.h > > - patch number changed from 3 to 4 > > > > MAINTAINERS | 1 + > > drivers/tty/serial/Kconfig | 30 +++ > > drivers/tty/serial/Makefile | 1 + > > drivers/tty/serial/liteuart.c | 373 +++++++++++++++++++++++++++++++ > > include/uapi/linux/serial_core.h | 3 + > > 5 files changed, 408 insertions(+) > > create mode 100644 drivers/tty/serial/liteuart.c > > > > diff --git a/MAINTAINERS b/MAINTAINERS > > index 1dc783c9edb7..c24a37833e78 100644 > > --- a/MAINTAINERS > > +++ b/MAINTAINERS > > @@ -9499,6 +9499,7 @@ M: Mateusz Holenko > > S: Maintained > > F: include/linux/litex.h > > F: Documentation/devicetree/bindings/*/litex,*.yaml > > +F: drivers/tty/serial/liteuart.c > > > > LIVE PATCHING > > M: Josh Poimboeuf > > diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig > > index 4789b5d62f63..b01fe12a1411 100644 > > --- a/drivers/tty/serial/Kconfig > > +++ b/drivers/tty/serial/Kconfig > > @@ -1571,6 +1571,36 @@ config SERIAL_MILBEAUT_USIO_CONSOLE > > receives all kernel messages and warnings and which allows logi= ns in > > single user mode). > > > > +config SERIAL_LITEUART > > + tristate "LiteUART serial port support" > > + depends on HAS_IOMEM > > + depends on OF > > + select SERIAL_CORE > > + help > > + This driver is for the FPGA-based LiteUART serial controller fr= om LiteX > > + SoC builder. > > + > > + Say 'Y' here if you wish to use the LiteUART serial controller. > > + Otherwise, say 'N'. > > + > > +config SERIAL_LITEUART_NR_PORTS > > + int "Number of LiteUART ports" > > + depends on SERIAL_LITEUART > > + default "1" > > + help > > + Set this to the number of serial ports you want the driver > > + to support. > > It's better if the driver supports a dynamic number of ports. Do you mean that the number of ports should be taken from the device tree when booting the kernel? This is exactly how it works right now. The SERIAL_LITEUART_NR_PORTS just defines the maximum number of supported ports. I can rename the config to SERIAL_LITEUART_MAX_NR_PORTS to make it clearer, what do you think? > > + > > +config SERIAL_LITEUART_CONSOLE > > + bool "LiteUART serial port console support" > > + depends on SERIAL_LITEUART=3Dy > > + select SERIAL_CORE_CONSOLE > > + help > > + Say 'Y' here if you wish to use the FPGA-based LiteUART serial = controller > > + from LiteX SoC builder as the system console (the system consol= e is the > > + device which receives all kernel messages and warnings and whic= h allows > > + logins in single user mode). Otherwise, say 'N'. > > + > > endmenu > > > > config SERIAL_MCTRL_GPIO > > diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile > > index 863f47056539..c8d7e2046284 100644 > > --- a/drivers/tty/serial/Makefile > > +++ b/drivers/tty/serial/Makefile > > @@ -89,6 +89,7 @@ obj-$(CONFIG_SERIAL_OWL) +=3D owl-uart.o > > obj-$(CONFIG_SERIAL_RDA) +=3D rda-uart.o > > obj-$(CONFIG_SERIAL_MILBEAUT_USIO) +=3D milbeaut_usio.o > > obj-$(CONFIG_SERIAL_SIFIVE) +=3D sifive.o > > +obj-$(CONFIG_SERIAL_LITEUART) +=3D liteuart.o > > > > # GPIOLIB helpers for modem control lines > > obj-$(CONFIG_SERIAL_MCTRL_GPIO) +=3D serial_mctrl_gpio.o > > diff --git a/drivers/tty/serial/liteuart.c b/drivers/tty/serial/liteuar= t.c > > new file mode 100644 > > index 000000000000..e142f78df57a > > --- /dev/null > > +++ b/drivers/tty/serial/liteuart.c > > @@ -0,0 +1,373 @@ > > +// SPDX-License-Identifier: GPL-2.0 > > +/* > > + * LiteUART serial controller (LiteX) Driver > > + * > > + * Copyright (C) 2019 Antmicro Ltd > > + */ > > + > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > + > > +/* module-related defines */ > > +#define DRIVER_NAME "liteuart" > > +#define DRIVER_MAJOR 0 > > +#define DRIVER_MINOR 0 > > +#define DEV_NAME "ttyLXU" > > + > > +/* base address offsets */ > > +#define OFF_RXTX 0x00 > > +#define OFF_TXFULL 0x04 > > +#define OFF_RXEMPTY 0x08 > > +#define OFF_EV_STATUS 0x0c > > +#define OFF_EV_PENDING 0x10 > > +#define OFF_EV_ENABLE 0x14 > > + > > +/* events */ > > +#define EV_TX 0x1 > > +#define EV_RX 0x2 > > + > > +struct liteuart_port { > > + struct uart_port port; > > + struct timer_list timer; > > +}; > > + > > +#define to_liteuart_port(port) container_of(port, struct liteuar= t_port, port) > > + > > +static struct liteuart_port liteuart_ports[CONFIG_SERIAL_LITEUART_NR_P= ORTS]; > > + > > +#ifdef CONFIG_SERIAL_LITEUART_CONSOLE > > +static struct console liteuart_console; > > +#endif > > + > > +static struct uart_driver liteuart_driver =3D { > > + .owner =3D THIS_MODULE, > > + .driver_name =3D DRIVER_NAME, > > + .dev_name =3D DEV_NAME, > > + .major =3D DRIVER_MAJOR, > > + .minor =3D DRIVER_MINOR, > > + .nr =3D CONFIG_SERIAL_LITEUART_NR_PORTS, > > +#ifdef CONFIG_SERIAL_LITEUART_CONSOLE > > + .cons =3D &liteuart_console, > > +#endif > > +}; > > + > > +static void liteuart_timer(struct timer_list *t) > > +{ > > + struct liteuart_port *uart =3D from_timer(uart, t, timer); > > + struct uart_port *port =3D &uart->port; > > + unsigned char __iomem *membase =3D port->membase; > > + unsigned int flg =3D TTY_NORMAL; > > + int ch; > > + unsigned int status; > > + > > + while ((status =3D !LITEX_READ_REG_OFF(membase, OFF_RXEMPTY)) =3D= =3D 1) { > > + ch =3D LITEX_READ_REG_OFF(membase, OFF_RXTX); > > + port->icount.rx++; > > + > > + /* necessary for RXEMPTY to refresh its value */ > > + LITEX_WRITE_REG_OFF(EV_TX | EV_RX, membase, OFF_EV_PENDIN= G); > > + > > + /* no overflow bits in status */ > > + if (!(uart_handle_sysrq_char(port, ch))) > > + uart_insert_char(port, status, 0, ch, flg); > > + > > + tty_flip_buffer_push(&port->state->port); > > + } > > + > > + mod_timer(&uart->timer, jiffies + uart_poll_timeout(port)); > > +} > > + > > +static void liteuart_putchar(struct uart_port *port, int ch) > > +{ > > + while (LITEX_READ_REG_OFF(port->membase, OFF_TXFULL)) > > + cpu_relax(); > > + > > + LITEX_WRITE_REG_OFF(ch, port->membase, OFF_RXTX); > > +} > > + > > +static unsigned int liteuart_tx_empty(struct uart_port *port) > > +{ > > + /* not really tx empty, just checking if tx is not full */ > > + if (!LITEX_READ_REG_OFF(port->membase, OFF_TXFULL)) > > + return TIOCSER_TEMT; > > + > > + return 0; > > +} > > + > > +static void liteuart_set_mctrl(struct uart_port *port, unsigned int mc= trl) > > +{ > > + /* modem control register is not present in LiteUART */ > > +} > > + > > +static unsigned int liteuart_get_mctrl(struct uart_port *port) > > +{ > > + return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR; > > +} > > + > > +static void liteuart_stop_tx(struct uart_port *port) > > +{ > > +} > > + > > +static void liteuart_start_tx(struct uart_port *port) > > +{ > > + struct circ_buf *xmit =3D &port->state->xmit; > > + unsigned char ch; > > + > > + if (unlikely(port->x_char)) { > > + LITEX_WRITE_REG_OFF(port->x_char, port->membase, OFF_RXTX= ); > > + port->icount.tx++; > > + port->x_char =3D 0; > > + } else if (!uart_circ_empty(xmit)) { > > + while (xmit->head !=3D xmit->tail) { > > + ch =3D xmit->buf[xmit->tail]; > > + xmit->tail =3D (xmit->tail + 1) & (UART_XMIT_SIZE= - 1); > > + port->icount.tx++; > > + liteuart_putchar(port, ch); > > + } > > + } > > + > > + if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) > > + uart_write_wakeup(port); > > +} > > + > > +static void liteuart_stop_rx(struct uart_port *port) > > +{ > > + struct liteuart_port *uart =3D to_liteuart_port(port); > > + > > + /* just delete timer */ > > + del_timer(&uart->timer); > > +} > > + > > +static void liteuart_break_ctl(struct uart_port *port, int break_state= ) > > +{ > > + /* LiteUART doesn't support sending break signal */ > > +} > > + > > +static int liteuart_startup(struct uart_port *port) > > +{ > > + struct liteuart_port *uart =3D to_liteuart_port(port); > > + > > + /* disable events */ > > + LITEX_WRITE_REG_OFF(0, port->membase, OFF_EV_ENABLE); > > + > > + /* prepare timer for polling */ > > + timer_setup(&uart->timer, liteuart_timer, 0); > > + mod_timer(&uart->timer, jiffies + uart_poll_timeout(port)); > > + > > + return 0; > > +} > > + > > +static void liteuart_shutdown(struct uart_port *port) > > +{ > > +} > > + > > +static void liteuart_set_termios(struct uart_port *port, struct ktermi= os *new, > > + struct ktermios *old) > > +{ > > + unsigned int baud; > > + unsigned long flags; > > + > > + spin_lock_irqsave(&port->lock, flags); > > + > > + /* update baudrate */ > > + baud =3D uart_get_baud_rate(port, new, old, 0, 460800); > > + uart_update_timeout(port, new->c_cflag, baud); > > + > > + spin_unlock_irqrestore(&port->lock, flags); > > +} > > + > > +static const char *liteuart_type(struct uart_port *port) > > +{ > > + return (port->type =3D=3D PORT_LITEUART) ? DRIVER_NAME : NULL; > > +} > > + > > +static void liteuart_release_port(struct uart_port *port) > > +{ > > +} > > + > > +static int liteuart_request_port(struct uart_port *port) > > +{ > > + return 0; > > +} > > + > > +static void liteuart_config_port(struct uart_port *port, int flags) > > +{ > > + if (flags & UART_CONFIG_TYPE) > > + port->type =3D PORT_LITEUART; > > +} > > + > > +static int liteuart_verify_port(struct uart_port *port, > > + struct serial_struct *ser) > > +{ > > + if (port->type !=3D PORT_UNKNOWN && ser->type !=3D PORT_LITEUART) > > + return -EINVAL; > > + > > + return 0; > > +} > > + > > +static const struct uart_ops liteuart_ops =3D { > > + .tx_empty =3D liteuart_tx_empty, > > + .set_mctrl =3D liteuart_set_mctrl, > > + .get_mctrl =3D liteuart_get_mctrl, > > + .stop_tx =3D liteuart_stop_tx, > > + .start_tx =3D liteuart_start_tx, > > + .stop_rx =3D liteuart_stop_rx, > > + .break_ctl =3D liteuart_break_ctl, > > + .startup =3D liteuart_startup, > > + .shutdown =3D liteuart_shutdown, > > + .set_termios =3D liteuart_set_termios, > > + .type =3D liteuart_type, > > + .release_port =3D liteuart_release_port, > > + .request_port =3D liteuart_request_port, > > + .config_port =3D liteuart_config_port, > > + .verify_port =3D liteuart_verify_port, > > +}; > > + > > +static int liteuart_probe(struct platform_device *pdev) > > +{ > > + struct device_node *np =3D pdev->dev.of_node; > > + struct liteuart_port *uart; > > + struct uart_port *port; > > + int dev_id; > > + > > + /* no device tree */ > > + if (!np) > > + return -ENODEV; > > + > > + dev_id =3D of_alias_get_id(np, "serial"); > > + if (dev_id < 0 || dev_id >=3D CONFIG_SERIAL_LITEUART_NR_PORTS) > > + return -EINVAL; > > aliases should be optional. There's a helper to get a free index without > an alias you can use. Sure, we will fix it in v4. --=20 Mateusz Holenko Antmicro Ltd | www.antmicro.com Roosevelta 22, 60-829 Poznan, Poland