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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 598EECA9EBC for ; Sat, 26 Oct 2019 00:13:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 177D420679 for ; Sat, 26 Oct 2019 00:13:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572048817; bh=HT/pXTAfCPR+Z4amocqVLUJe7Xd9BonvriBpfVr59wc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=gjpc98mBy77HWnNsZkWlBdC39JZZuhcQ68eXfD/pnbpfxpCzpX1YQHiy/D/ovSwHx 3pSs//ZgGVDIwb0goxAi3WDXbou7OtheTWCHOzJPnv9NqHM/yj0NGe5BrGjf5Nfjz3 TvFXB22FuOsXnAgAUTSp2MmeEcHOFzoyj/+9PsRM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725899AbfJZANe (ORCPT ); Fri, 25 Oct 2019 20:13:34 -0400 Received: from mail-oi1-f193.google.com ([209.85.167.193]:36640 "EHLO mail-oi1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725874AbfJZANe (ORCPT ); Fri, 25 Oct 2019 20:13:34 -0400 Received: by mail-oi1-f193.google.com with SMTP id j7so2755792oib.3; Fri, 25 Oct 2019 17:13:33 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=duK6trbNP7JlUkXTfwb/umRxfSmnp8aq8joQGSrnhZU=; b=ZtM6EZXU2XAVWGTcPi8pz19ndfE+Yd7lHu6Krg8ChwtizOyAwxB5Sz4iPc3n/Zi/7i o1I7Kwm1uwON4OU48Un2znlhce33yuv8CXH5AGS0sZqZQySc9FLcYyawtxY9G659iOEN NpqTztqyDs59A1eCeZJU9mm0NIFk0CE8yWKAQxZwjcDv4udOE1ARwMu7NWu66qyS67jP kvqCG5nrQCT2htfN6Jnpsiu/j8ClTdVRma7zYpMsjzjqwzyUw4EEHbm7cxExtyPomRYJ C6kiEeqI6HFGmOUkO+BSYMo9LpM6LH6hNdUOcI1wHCs7Gsg+y4DpfXqKHrPfr0+NJX2P xPPQ== X-Gm-Message-State: APjAAAV5XGB3+6c7yIP/ilPFn/erGbsN/BSLHsDgMsRXsL6ocukyTNDl OpXSPnvZX8jLs12NQ0RGGg== X-Google-Smtp-Source: APXvYqzL6RjgjxOcAy6qxRLhn6XE45tR4dRXqFEEYEt6OsHrRk2P1A/Ux5ij96ZFZCuLHfc2wP9ASA== X-Received: by 2002:aca:6701:: with SMTP id z1mr4962706oix.64.1572048812559; Fri, 25 Oct 2019 17:13:32 -0700 (PDT) Received: from localhost (24-155-109-49.dyn.grandenetworks.net. [24.155.109.49]) by smtp.gmail.com with ESMTPSA id s1sm1210890otd.49.2019.10.25.17.13.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 25 Oct 2019 17:13:31 -0700 (PDT) Date: Fri, 25 Oct 2019 19:13:31 -0500 From: Rob Herring To: Mateusz Holenko Cc: Mark Rutland , Greg Kroah-Hartman , Jiri Slaby , devicetree@vger.kernel.org, linux-serial@vger.kernel.org, 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 Subject: Re: [PATCH v2 4/4] drivers/tty/serial: add LiteUART driver Message-ID: <20191026001331.GB10810@bogus> References: <20191023114634.13657-0-mholenko@antmicro.com> <20191023114634.13657-4-mholenko@antmicro.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191023114634.13657-4-mholenko@antmicro.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-serial-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org 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 logins 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 from 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. > + > +config SERIAL_LITEUART_CONSOLE > + bool "LiteUART serial port console support" > + depends on SERIAL_LITEUART=y > + 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 console is the > + device which receives all kernel messages and warnings and which 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-$(CONFIG_SERIAL_OWL) += owl-uart.o > obj-$(CONFIG_SERIAL_RDA) += rda-uart.o > obj-$(CONFIG_SERIAL_MILBEAUT_USIO) += milbeaut_usio.o > obj-$(CONFIG_SERIAL_SIFIVE) += sifive.o > +obj-$(CONFIG_SERIAL_LITEUART) += liteuart.o > > # GPIOLIB helpers for modem control lines > obj-$(CONFIG_SERIAL_MCTRL_GPIO) += serial_mctrl_gpio.o > diff --git a/drivers/tty/serial/liteuart.c b/drivers/tty/serial/liteuart.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 liteuart_port, port) > + > +static struct liteuart_port liteuart_ports[CONFIG_SERIAL_LITEUART_NR_PORTS]; > + > +#ifdef CONFIG_SERIAL_LITEUART_CONSOLE > +static struct console liteuart_console; > +#endif > + > +static struct uart_driver liteuart_driver = { > + .owner = THIS_MODULE, > + .driver_name = DRIVER_NAME, > + .dev_name = DEV_NAME, > + .major = DRIVER_MAJOR, > + .minor = DRIVER_MINOR, > + .nr = CONFIG_SERIAL_LITEUART_NR_PORTS, > +#ifdef CONFIG_SERIAL_LITEUART_CONSOLE > + .cons = &liteuart_console, > +#endif > +}; > + > +static void liteuart_timer(struct timer_list *t) > +{ > + struct liteuart_port *uart = from_timer(uart, t, timer); > + struct uart_port *port = &uart->port; > + unsigned char __iomem *membase = port->membase; > + unsigned int flg = TTY_NORMAL; > + int ch; > + unsigned int status; > + > + while ((status = !LITEX_READ_REG_OFF(membase, OFF_RXEMPTY)) == 1) { > + ch = 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_PENDING); > + > + /* 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 mctrl) > +{ > + /* 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 = &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 = 0; > + } else if (!uart_circ_empty(xmit)) { > + while (xmit->head != xmit->tail) { > + ch = xmit->buf[xmit->tail]; > + xmit->tail = (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 = 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 = 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 ktermios *new, > + struct ktermios *old) > +{ > + unsigned int baud; > + unsigned long flags; > + > + spin_lock_irqsave(&port->lock, flags); > + > + /* update baudrate */ > + baud = 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 == 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 = PORT_LITEUART; > +} > + > +static int liteuart_verify_port(struct uart_port *port, > + struct serial_struct *ser) > +{ > + if (port->type != PORT_UNKNOWN && ser->type != PORT_LITEUART) > + return -EINVAL; > + > + return 0; > +} > + > +static const struct uart_ops liteuart_ops = { > + .tx_empty = liteuart_tx_empty, > + .set_mctrl = liteuart_set_mctrl, > + .get_mctrl = liteuart_get_mctrl, > + .stop_tx = liteuart_stop_tx, > + .start_tx = liteuart_start_tx, > + .stop_rx = liteuart_stop_rx, > + .break_ctl = liteuart_break_ctl, > + .startup = liteuart_startup, > + .shutdown = liteuart_shutdown, > + .set_termios = liteuart_set_termios, > + .type = liteuart_type, > + .release_port = liteuart_release_port, > + .request_port = liteuart_request_port, > + .config_port = liteuart_config_port, > + .verify_port = liteuart_verify_port, > +}; > + > +static int liteuart_probe(struct platform_device *pdev) > +{ > + struct device_node *np = pdev->dev.of_node; > + struct liteuart_port *uart; > + struct uart_port *port; > + int dev_id; > + > + /* no device tree */ > + if (!np) > + return -ENODEV; > + > + dev_id = of_alias_get_id(np, "serial"); > + if (dev_id < 0 || dev_id >= 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.