On 2022-10-04 16:37, matthew.gerlach@xxxxxxxxxxxxxxx wrote:
> From: Matthew Gerlach <matthew.gerlach@xxxxxxxxxxxxxxx>
>
> Add a Device Feature List (DFL) bus driver for the Altera
> 16550 implementation of UART.
>
> Signed-off-by: Matthew Gerlach <matthew.gerlach@xxxxxxxxxxxxxxx>
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> ---
> 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 | 177 +++++++++++++++++++++++++++++
> drivers/tty/serial/8250/Kconfig | 9 ++
> drivers/tty/serial/8250/Makefile | 1 +
> 3 files changed, 187 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..110ad3a73459
> --- /dev/null
> +++ b/drivers/tty/serial/8250/8250_dfl.c
> @@ -0,0 +1,177 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Driver for FPGA UART
> + *
> + * Copyright (C) 2022 Intel Corporation, Inc.
> + *
> + * Authors:
> + * Ananda Ravuri <ananda.ravuri@xxxxxxxxx>
> + * Matthew Gerlach <matthew.gerlach@xxxxxxxxxxxxxxx>
> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/dfl.h>
> +#include <linux/io-64-nonatomic-lo-hi.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/serial.h>
> +#include <linux/serial_8250.h>
> +
> +struct dfl_uart {
> + int line;
> +};
> +
> +static int dfl_uart_get_params(struct device *dev, void __iomem *dfh_base, resource_size_t max,
> + struct uart_8250_port *uart)
> +{
> + u64 v, fifo_len, reg_width;
> + int off;
> +
> + if (!dfhv1_has_params(dfh_base)) {
> + dev_err(dev, "missing required DFH parameters\n");
> + return -EINVAL;
> + }
> +
> + off = dfhv1_find_param(dfh_base, max, DFHv1_PARAM_ID_CLK_FRQ);
> + if (off < 0) {
> + dev_err(dev, "missing CLK_FRQ param\n");
> + return -EINVAL;
> + }
> +
> + uart->port.uartclk = readq(dfh_base + off);
> + dev_dbg(dev, "UART_CLK_ID %u Hz\n", uart->port.uartclk);
> +
> + off = dfhv1_find_param(dfh_base, max, DFHv1_PARAM_ID_FIFO_LEN);
> + if (off < 0) {
> + dev_err(dev, "missing FIFO_LEN param\n");
> + return -EINVAL;
> + }
> +
> + fifo_len = readq(dfh_base + off);
> + dev_dbg(dev, "UART_FIFO_ID fifo_len %llu\n", fifo_len);
> +
> + 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:
> + dev_err(dev, "bad fifo_len %llu\n", fifo_len);
> + return -EINVAL;
> + }
> +
> + off = dfhv1_find_param(dfh_base, max, DFHv1_PARAM_ID_REG_LAYOUT);
> + if (off < 0) {
> + dev_err(dev, "missing REG_LAYOUT param\n");
> + return -EINVAL;
> + }
> +
> + v = readq(dfh_base + off);
> + uart->port.regshift = FIELD_GET(DFHv1_PARAM_ID_REG_SHIFT, v);
> + reg_width = FIELD_GET(DFHv1_PARAM_ID_REG_WIDTH, v);
> +
> + dev_dbg(dev, "UART_LAYOUT_ID width %lld shift %d\n",
> + FIELD_GET(DFHv1_PARAM_ID_REG_WIDTH, v), (int)uart->port.regshift);
> +
> + switch (reg_width) {
> + case 4:
> + uart->port.iotype = UPIO_MEM32;
> + break;
> +
> + case 2:
> + uart->port.iotype = UPIO_MEM16;
> + break;
> +
> + default:
> + dev_err(dev, "invalid reg_width %lld\n", reg_width);
> + return -EINVAL;
> + }
> +
> + 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;
> + resource_size_t res_size;
> + void __iomem *dfh_base;
> + int ret;
> +
> + memset(&uart, 0, sizeof(uart));
> + uart.port.flags = UPF_IOREMAP;
> + uart.port.mapbase = dfl_dev->csr_res.start;
> + uart.port.mapsize = resource_size(&dfl_dev->csr_res);
> +
> + dfluart = devm_kzalloc(dev, sizeof(*dfluart), GFP_KERNEL);
> + if (!dfluart)
> + return -ENOMEM;
> +
> + dfh_base = devm_ioremap_resource(dev, &dfl_dev->mmio_res);
> + if (IS_ERR(dfh_base))
> + return PTR_ERR(dfh_base);
> +
> + res_size = resource_size(&dfl_dev->mmio_res);
> +
> + ret = dfl_uart_get_params(dev, dfh_base, res_size, &uart);
It seems to me that the dfl_uart driver supports only DFHv1 headers.
So why not checking dfl_dev->dfh_version in dfl_uart_probe() before
allocating, mapping, and then checking with dfl_uart_get_params()?
> +
> + devm_iounmap(dev, dfh_base);
> + devm_release_mem_region(dev, dfl_dev->mmio_res.start, res_size);
> +
> + if (ret < 0)
> + return dev_err_probe(dev, ret, "failed uart feature walk\n");
> +
> + dev_dbg(dev, "nr_irqs %d %p\n", dfl_dev->num_irqs, dfl_dev->irqs);
> +
> + if (dfl_dev->num_irqs == 1)
> + uart.port.irq = dfl_dev->irqs[0];
> +
> + /* register the port */
> + 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_info(dev, "serial8250_register_8250_port %d\n", dfluart->line);
> + 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);
> +
> + if (dfluart->line >= 0)
> + 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 d0b49e15fbf5..5c6497ce5c12 100644
> --- a/drivers/tty/serial/8250/Kconfig
> +++ b/drivers/tty/serial/8250/Kconfig
> @@ -361,6 +361,15 @@ config SERIAL_8250_BCM2835AUX
>
> If unsure, say N.
>
> +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.
> +
> config SERIAL_8250_FSL
> bool "Freescale 16550 UART support" if COMPILE_TEST && !(PPC || ARM || ARM64)
> depends on SERIAL_8250_CONSOLE
> diff --git a/drivers/tty/serial/8250/Makefile b/drivers/tty/serial/8250/Makefile
> index bee908f99ea0..32006e0982d1 100644
> --- a/drivers/tty/serial/8250/Makefile
> +++ b/drivers/tty/serial/8250/Makefile
> @@ -24,6 +24,7 @@ obj-$(CONFIG_SERIAL_8250_CONSOLE) += 8250_early.o
> obj-$(CONFIG_SERIAL_8250_FOURPORT) += 8250_fourport.o
> obj-$(CONFIG_SERIAL_8250_ACCENT) += 8250_accent.o
> obj-$(CONFIG_SERIAL_8250_BOCA) += 8250_boca.o
> +obj-$(CONFIG_SERIAL_8250_DFL) += 8250_dfl.o
> obj-$(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
Thanks,
Marco
