diff options
Diffstat (limited to 'drivers/tty/serial/8250/8250_dfl.c')
| -rw-r--r-- | drivers/tty/serial/8250/8250_dfl.c | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/drivers/tty/serial/8250/8250_dfl.c b/drivers/tty/serial/8250/8250_dfl.c new file mode 100644 index 000000000000..6c5ff019df4b --- /dev/null +++ b/drivers/tty/serial/8250/8250_dfl.c @@ -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(*pval)) + 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"); |