new file mode 100644
@@ -0,0 +1,167 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for FPGA UART
+ *
+ * Copyright (C) 2022 Intel Corporation.
+ *
+ * Authors:
+ * Ananda Ravuri <ananda.ravuri@intel.com>
+ * Matthew Gerlach <matthew.gerlach@linux.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 dfh_get_u64_param_val(struct dfl_device *dfl_dev, int param_id, u64 *pval)
+{
+ size_t psize;
+ u64 *p;
+
+ p = dfh_find_param(dfl_dev, param_id, &psize);
+ if (IS_ERR(p))
+ return PTR_ERR(p);
+
+ if (psize != sizeof(u64))
+ return -EINVAL;
+
+ *pval = *p;
+
+ return 0;
+}
+
+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;
+ int ret;
+
+ ret = dfh_get_u64_param_val(dfl_dev, DFHv1_PARAM_ID_CLK_FRQ, &clk_freq);
+ if (ret)
+ return dev_err_probe(dev, ret, "missing CLK_FRQ param\n");
+
+ uart->port.uartclk = clk_freq;
+
+ ret = dfh_get_u64_param_val(dfl_dev, DFHv1_PARAM_ID_FIFO_LEN, &fifo_len);
+ if (ret)
+ return dev_err_probe(dev, ret, "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);
+ }
+
+ ret = dfh_get_u64_param_val(dfl_dev, DFHv1_PARAM_ID_REG_LAYOUT, ®_layout);
+ if (ret)
+ return dev_err_probe(dev, ret, "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");
@@ -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
@@ -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