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Message-ID: <alpine.DEB.2.22.394.2212290932310.1857691@rhweight-WRK1>
Date: Thu, 29 Dec 2022 09:33:38 -0800 (PST)
From: matthew.gerlach@...ux.intel.com
To: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
cc: hao.wu@...el.com, yilun.xu@...el.com, russell.h.weight@...el.com,
basheer.ahmed.muddebihal@...el.com, trix@...hat.com,
mdf@...nel.org, linux-fpga@...r.kernel.org,
linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
tianfei.zhang@...el.com, corbet@....net,
gregkh@...uxfoundation.org, linux-serial@...r.kernel.org,
jirislaby@...nel.org, geert+renesas@...der.be,
niklas.soderlund+renesas@...natech.se, macro@...am.me.uk,
johan@...nel.org, lukas@...ner.de, ilpo.jarvinen@...ux.intel.com,
marpagan@...hat.com, bagasdotme@...il.com
Subject: Re: [PATCH v8 4/4] tty: serial: 8250: add DFL bus driver for Altera
16550.
On Thu, 29 Dec 2022, Andy Shevchenko wrote:
> On Wed, Dec 28, 2022 at 10:16:24AM -0800, matthew.gerlach@...ux.intel.com wrote:
>> From: Matthew Gerlach <matthew.gerlach@...ux.intel.com>
>>
>> Add a Device Feature List (DFL) bus driver for the Altera
>> 16550 implementation of UART.
>
> With that helper looks better,
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
I agree the helper function makes the code look better and is safer.
Thanks for the review,
Matthew Gerlach
>
>> Signed-off-by: Matthew Gerlach <matthew.gerlach@...ux.intel.com>
>> Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
>> ---
>> v8: use dfh_get_u64_param_vals()
>>
>> v7: no change
>>
>> v6: move driver specific parameter definitions to limit scope
>>
>> v5: removed unneeded blank line
>> removed unneeded includes
>> included device.h and types.h
>> removed unneeded local variable
>> remove calls to dev_dbg
>> memset -> { }
>> remove space after period
>> explicitly include used headers
>> remove redundant Inc from Copyright
>> fix format specifier
>>
>> v4: use dev_err_probe() everywhere that is appropriate
>> clean up noise
>> change error messages to use the word, unsupported
>> tried again to sort Makefile and KConfig better
>> reorder probe function for easier error handling
>> use new dfh_find_param API
>>
>> v3: use passed in location of registers
>> use cleaned up functions for parsing parameters
>>
>> v2: clean up error messages
>> alphabetize header files
>> fix 'missing prototype' error by making function static
>> tried to sort Makefile and Kconfig better
>> ---
>> drivers/tty/serial/8250/8250_dfl.c | 150 +++++++++++++++++++++++++++++
>> drivers/tty/serial/8250/Kconfig | 12 +++
>> drivers/tty/serial/8250/Makefile | 1 +
>> 3 files changed, 163 insertions(+)
>> create mode 100644 drivers/tty/serial/8250/8250_dfl.c
>>
>> diff --git a/drivers/tty/serial/8250/8250_dfl.c b/drivers/tty/serial/8250/8250_dfl.c
>> new file mode 100644
>> index 000000000000..0ee78c38a721
>> --- /dev/null
>> +++ b/drivers/tty/serial/8250/8250_dfl.c
>> @@ -0,0 +1,150 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Driver for FPGA UART
>> + *
>> + * Copyright (C) 2022 Intel Corporation.
>> + *
>> + * Authors:
>> + * Ananda Ravuri <ananda.ravuri@...el.com>
>> + * Matthew Gerlach <matthew.gerlach@...ux.intel.com>
>> + */
>> +
>> +#include <linux/bitfield.h>
>> +#include <linux/device.h>
>> +#include <linux/dfl.h>
>> +#include <linux/errno.h>
>> +#include <linux/ioport.h>
>> +#include <linux/module.h>
>> +#include <linux/mod_devicetable.h>
>> +#include <linux/types.h>
>> +
>> +#include <linux/serial.h>
>> +#include <linux/serial_8250.h>
>> +
>> +#define DFHv1_PARAM_ID_CLK_FRQ 0x2
>> +#define DFHv1_PARAM_ID_FIFO_LEN 0x3
>> +
>> +#define DFHv1_PARAM_ID_REG_LAYOUT 0x4
>> +#define DFHv1_PARAM_REG_LAYOUT_WIDTH GENMASK_ULL(63, 32)
>> +#define DFHv1_PARAM_REG_LAYOUT_SHIFT GENMASK_ULL(31, 0)
>> +
>> +struct dfl_uart {
>> + int line;
>> +};
>> +
>> +static int dfl_uart_get_params(struct dfl_device *dfl_dev, struct uart_8250_port *uart)
>> +{
>> + struct device *dev = &dfl_dev->dev;
>> + u64 fifo_len, clk_freq, reg_layout;
>> + u32 reg_width;
>> + u64 *p;
>> +
>> + p = dfh_get_u64_param_vals(dfl_dev, DFHv1_PARAM_ID_CLK_FRQ, &clk_freq, 1);
>> + if (IS_ERR(p))
>> + return dev_err_probe(dev, PTR_ERR(p), "missing CLK_FRQ param\n");
>> +
>> + uart->port.uartclk = clk_freq;
>> +
>> + p = dfh_get_u64_param_vals(dfl_dev, DFHv1_PARAM_ID_FIFO_LEN, &fifo_len, 1);
>> + if (IS_ERR(p))
>> + return dev_err_probe(dev, PTR_ERR(p), "missing FIFO_LEN param\n");
>> +
>> + switch (fifo_len) {
>> + case 32:
>> + uart->port.type = PORT_ALTR_16550_F32;
>> + break;
>> +
>> + case 64:
>> + uart->port.type = PORT_ALTR_16550_F64;
>> + break;
>> +
>> + case 128:
>> + uart->port.type = PORT_ALTR_16550_F128;
>> + break;
>> +
>> + default:
>> + return dev_err_probe(dev, -EINVAL, "unsupported FIFO_LEN %llu\n", fifo_len);
>> + }
>> +
>> + p = dfh_get_u64_param_vals(dfl_dev, DFHv1_PARAM_ID_REG_LAYOUT, ®_layout, 1);
>> + if (IS_ERR(p))
>> + return dev_err_probe(dev, PTR_ERR(p), "missing REG_LAYOUT param\n");
>> +
>> + uart->port.regshift = FIELD_GET(DFHv1_PARAM_REG_LAYOUT_SHIFT, reg_layout);
>> + reg_width = FIELD_GET(DFHv1_PARAM_REG_LAYOUT_WIDTH, reg_layout);
>> + switch (reg_width) {
>> + case 4:
>> + uart->port.iotype = UPIO_MEM32;
>> + break;
>> +
>> + case 2:
>> + uart->port.iotype = UPIO_MEM16;
>> + break;
>> +
>> + default:
>> + return dev_err_probe(dev, -EINVAL, "unsupported reg-width %u\n", reg_width);
>> +
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static int dfl_uart_probe(struct dfl_device *dfl_dev)
>> +{
>> + struct device *dev = &dfl_dev->dev;
>> + struct uart_8250_port uart = { };
>> + struct dfl_uart *dfluart;
>> + int ret;
>> +
>> + uart.port.flags = UPF_IOREMAP;
>> + uart.port.mapbase = dfl_dev->mmio_res.start;
>> + uart.port.mapsize = resource_size(&dfl_dev->mmio_res);
>> +
>> + ret = dfl_uart_get_params(dfl_dev, &uart);
>> + if (ret < 0)
>> + return dev_err_probe(dev, ret, "failed uart feature walk\n");
>> +
>> + if (dfl_dev->num_irqs == 1)
>> + uart.port.irq = dfl_dev->irqs[0];
>> +
>> + dfluart = devm_kzalloc(dev, sizeof(*dfluart), GFP_KERNEL);
>> + if (!dfluart)
>> + return -ENOMEM;
>> +
>> + dfluart->line = serial8250_register_8250_port(&uart);
>> + if (dfluart->line < 0)
>> + return dev_err_probe(dev, dfluart->line, "unable to register 8250 port.\n");
>> +
>> + dev_set_drvdata(dev, dfluart);
>> +
>> + return 0;
>> +}
>> +
>> +static void dfl_uart_remove(struct dfl_device *dfl_dev)
>> +{
>> + struct dfl_uart *dfluart = dev_get_drvdata(&dfl_dev->dev);
>> +
>> + serial8250_unregister_port(dfluart->line);
>> +}
>> +
>> +#define FME_FEATURE_ID_UART 0x24
>> +
>> +static const struct dfl_device_id dfl_uart_ids[] = {
>> + { FME_ID, FME_FEATURE_ID_UART },
>> + { }
>> +};
>> +MODULE_DEVICE_TABLE(dfl, dfl_uart_ids);
>> +
>> +static struct dfl_driver dfl_uart_driver = {
>> + .drv = {
>> + .name = "dfl-uart",
>> + },
>> + .id_table = dfl_uart_ids,
>> + .probe = dfl_uart_probe,
>> + .remove = dfl_uart_remove,
>> +};
>> +module_dfl_driver(dfl_uart_driver);
>> +
>> +MODULE_DESCRIPTION("DFL Intel UART driver");
>> +MODULE_AUTHOR("Intel Corporation");
>> +MODULE_LICENSE("GPL");
>> diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
>> index b0f62345bc84..08af2acd4645 100644
>> --- a/drivers/tty/serial/8250/Kconfig
>> +++ b/drivers/tty/serial/8250/Kconfig
>> @@ -370,6 +370,18 @@ config SERIAL_8250_FSL
>> erratum for Freescale 16550 UARTs in the 8250 driver. It also
>> enables support for ACPI enumeration.
>>
>> +config SERIAL_8250_DFL
>> + tristate "DFL bus driver for Altera 16550 UART"
>> + depends on SERIAL_8250 && FPGA_DFL
>> + help
>> + This option enables support for a Device Feature List (DFL) bus
>> + driver for the Altera 16650 UART. One or more Altera 16650 UARTs
>> + can be instantiated in a FPGA and then be discovered during
>> + enumeration of the DFL bus.
>> +
>> + To compile this driver as a module, chose M here: the
>> + module will be called 8250_dfl.
>> +
>> config SERIAL_8250_DW
>> tristate "Support for Synopsys DesignWare 8250 quirks"
>> depends on SERIAL_8250
>> diff --git a/drivers/tty/serial/8250/Makefile b/drivers/tty/serial/8250/Makefile
>> index 1615bfdde2a0..4e1a32812683 100644
>> --- a/drivers/tty/serial/8250/Makefile
>> +++ b/drivers/tty/serial/8250/Makefile
>> @@ -28,6 +28,7 @@ obj-$(CONFIG_SERIAL_8250_EXAR_ST16C554) += 8250_exar_st16c554.o
>> obj-$(CONFIG_SERIAL_8250_HUB6) += 8250_hub6.o
>> obj-$(CONFIG_SERIAL_8250_FSL) += 8250_fsl.o
>> obj-$(CONFIG_SERIAL_8250_MEN_MCB) += 8250_men_mcb.o
>> +obj-$(CONFIG_SERIAL_8250_DFL) += 8250_dfl.o
>> obj-$(CONFIG_SERIAL_8250_DW) += 8250_dw.o
>> obj-$(CONFIG_SERIAL_8250_EM) += 8250_em.o
>> obj-$(CONFIG_SERIAL_8250_IOC3) += 8250_ioc3.o
>> --
>> 2.25.1
>>
>
> --
> With Best Regards,
> Andy Shevchenko
>
>
>
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