RE: [EXT] [PATCH v3] serial: 8250_fsl: Add ACPI support

[Kuldip Dwivedi <kuldip.dwivedi@puresoftware.com>]

> -----Original Message-----
> From: Vabhav Sharma (OSS) <vabhav.sharma@oss.nxp.com>
> Sent: Wednesday, September 2, 2020 9:10 PM
> To: kuldip dwivedi <kuldip.dwivedi@puresoftware.com>; Greg Kroah-Hartman
> <gregkh@linuxfoundation.org>; Jiri Slaby <jirislaby@kernel.org>; Dmitry
Safonov
> <0x7f454c46@gmail.com>; linux-serial@vger.kernel.org
> Cc: Pankaj Bansal <pankaj.bansal@nxp.com>; Varun Sethi
<V.Sethi@nxp.com>;
> Arokia Samy <arokia.samy@nxp.com>; kuldip dwivedi
> <kuldip.dwivedi@puresoftware.com>
> Subject: RE: [EXT] [PATCH v3] serial: 8250_fsl: Add ACPI support
>
>
> > -----Original Message-----
> > From: kuldip dwivedi <kuldip.dwivedi@puresoftware.com>
> > Sent: Saturday, August 29, 2020 8:13 PM
> > To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>; Jiri Slaby
> > <jirislaby@kernel.org>; Dmitry Safonov <0x7f454c46@gmail.com>; linux-
> > serial@vger.kernel.org
> > Cc: Vabhav Sharma <vabhav.sharma@nxp.com>; Pankaj Bansal
> > <pankaj.bansal@nxp.com>; Varun Sethi <V.Sethi@nxp.com>; Arokia Samy
> > <arokia.samy@nxp.com>; kuldip dwivedi
> > <kuldip.dwivedi@puresoftware.com>
> > Subject: [EXT] [PATCH v3] serial: 8250_fsl: Add ACPI support
> >
> > Caution: EXT Email
> >
> > This adds support for ACPI enumerated FSL 16550 UARTs.
> > For supporting ACPI, I added a wrapper so that this driver can be used
> > if firmware has exposed the HID "NXP0018" in DSDT table.
> >
> > This will be built as object file if config "SERIAL_8250_FSL"
> > is enabled which depends on config "SERIAL_8250_CONSOLE".
> >
> > Signed-off-by: kuldip dwivedi <kuldip.dwivedi@puresoftware.com>
> > ---
> >
> > Notes:
> >     1. Move Copyright and File description at top of the file
> >     2. Add ACPI wrapper code within CONFIG_ACPI macro
> >     3. this change is tested with DT and ACPI boot on LS1046A platform
> >
> >  drivers/tty/serial/8250/8250_fsl.c | 108
> > +++++++++++++++++++++++++++--
> >  1 file changed, 101 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/tty/serial/8250/8250_fsl.c
> > b/drivers/tty/serial/8250/8250_fsl.c
> > index 0d0c80905c58..68bfbf392281 100644
> > --- a/drivers/tty/serial/8250/8250_fsl.c
> > +++ b/drivers/tty/serial/8250/8250_fsl.c
> > @@ -1,15 +1,12 @@
> >  // SPDX-License-Identifier: GPL-2.0
> > -#include <linux/serial_reg.h>
> > -#include <linux/serial_8250.h>
> > -
> > -#include "8250.h"
> > -
> >  /*
> >   * Freescale 16550 UART "driver", Copyright (C) 2011 Paul Gortmaker.
> > + * Copyright 2020 NXP
> > + * Copyright 2020 Puresoftware Ltd.
> >   *
> >   * This isn't a full driver; it just provides an alternate IRQ
> > - * handler to deal with an errata.  Everything else is just
> > - * using the bog standard 8250 support.
> > + * handler to deal with an errata and provide ACPI wrapper.
> > + * Everything else is just using the bog standard 8250 support.
> >   *
> >   * We follow code flow of serial8250_default_handle_irq() but add
> >   * a check for a break and insert a dummy read on the Rx for the @@
> > -20,6
> > +17,16 @@
> >   * IRQ event to the next one.
> >   */
> >
> > +#include <linux/acpi.h>
> > +#include <linux/serial_reg.h>
> > +#include <linux/serial_8250.h>
> > +
> > +#include "8250.h"
> > +
> > +struct fsl8250_data {
> > +       int     line;
> > +};
> > +
> >  int fsl8250_handle_irq(struct uart_port *port)  {
> >         unsigned char lsr, orig_lsr;
> > @@ -79,3 +86,90 @@ int fsl8250_handle_irq(struct uart_port *port)
> >         return 1;
> >  }
> >  EXPORT_SYMBOL_GPL(fsl8250_handle_irq);
> > +
> > +#ifdef CONFIG_ACPI
> > +static int fsl8250_acpi_probe(struct platform_device *pdev) {
> > +       struct fsl8250_data *data;
> > +       struct uart_8250_port port8250;
> > +       struct device *dev = &pdev->dev;
> > +       struct resource *regs;
> > +
> > +       int ret, irq;
> > +
> > +       regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > +       if (!regs) {
> > +               dev_err(dev, "no registers defined\n");
> > +               return -EINVAL;
> > +       }
> > +
> > +       irq = platform_get_irq(pdev, 0);
> > +       if (irq < 0) {
> > +               if (irq != -EPROBE_DEFER)
> > +                       dev_err(dev, "cannot get irq\n");
> > +               return irq;
> > +       }
> > +
> > +       memset(&port8250, 0, sizeof(port8250));
> > +
> > +       ret = device_property_read_u32(dev, "clock-frequency",
> > +                                       &port8250.port.uartclk);
> > +       if (ret)
> > +               return ret;
> > +
> > +       spin_lock_init(&port8250.port.lock);
> > +
> > +       port8250.port.mapbase           = regs->start;
> > +       port8250.port.irq               = irq;
> > +       port8250.port.handle_irq        = fsl8250_handle_irq;
> > +       port8250.port.type              = PORT_16550A;
> > +       port8250.port.flags             = UPF_SHARE_IRQ |
UPF_BOOT_AUTOCONF
> > +                                               | UPF_FIXED_PORT |
UPF_IOREMAP
> > +                                               | UPF_FIXED_TYPE;
> > +       port8250.port.dev               = dev;
> > +       port8250.port.mapsize           = resource_size(regs);
> > +       port8250.port.iotype            = UPIO_MEM;
> > +       port8250.port.irqflags          = IRQF_SHARED;
> > +
> > +       port8250.port.membase = devm_ioremap(dev,
port8250.port.mapbase,
> > +
port8250.port.mapsize);
> > +       if (!port8250.port.membase)
> > +               return -ENOMEM;
> > +
> > +       data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
> > +       if (!data)
> > +               return -ENOMEM;
> > +
> > +       data->line = serial8250_register_8250_port(&port8250);
> > +       if (data->line < 0)
> > +               ret = data->line;
> Would you like to return error here?
Addressed in v4
> > +
> > +       platform_set_drvdata(pdev, data);
> > +       return 0;
> > +}
> > +
> > +static int fsl8250_acpi_remove(struct platform_device *pdev) {
> > +       struct fsl8250_data *data = platform_get_drvdata(pdev);
> > +
> > +       serial8250_unregister_port(data->line);
> > +       return 0;
> > +}
> > +
> > +static const struct acpi_device_id fsl_8250_acpi_id[] = {
> > +       { "NXP0018", 0 },
> > +       { },
> > +};
> > +MODULE_DEVICE_TABLE(acpi, fsl_8250_acpi_id);
> > +
> > +static struct platform_driver fsl8250_platform_driver = {
> > +       .driver = {
> > +               .name                   = "fsl-16550-uart",
> > +               .acpi_match_table       = ACPI_PTR(fsl_8250_acpi_id),
> > +       },
> > +       .probe                  = fsl8250_acpi_probe,
> > +       .remove                 = fsl8250_acpi_remove,
> > +};
> > +
> > +module_platform_driver(fsl8250_platform_driver);
> > +#endif
> > --
> > 2.17.1