1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Driver for FPGA UART
4 *
5 * Copyright (C) 2022 Intel Corporation.
6 *
7 * Authors:
8 * Ananda Ravuri <ananda.ravuri@intel.com>
9 * Matthew Gerlach <matthew.gerlach@linux.intel.com>
10 */
11
12 #include <linux/bitfield.h>
13 #include <linux/device.h>
14 #include <linux/dfl.h>
15 #include <linux/errno.h>
16 #include <linux/ioport.h>
17 #include <linux/module.h>
18 #include <linux/mod_devicetable.h>
19 #include <linux/types.h>
20
21 #include <linux/serial.h>
22 #include <linux/serial_8250.h>
23
24 #define DFHv1_PARAM_ID_CLK_FRQ 0x2
25 #define DFHv1_PARAM_ID_FIFO_LEN 0x3
26
27 #define DFHv1_PARAM_ID_REG_LAYOUT 0x4
28 #define DFHv1_PARAM_REG_LAYOUT_WIDTH GENMASK_ULL(63, 32)
29 #define DFHv1_PARAM_REG_LAYOUT_SHIFT GENMASK_ULL(31, 0)
30
31 struct dfl_uart {
32 int line;
33 };
34
dfh_get_u64_param_val(struct dfl_device * dfl_dev,int param_id,u64 * pval)35 static int dfh_get_u64_param_val(struct dfl_device *dfl_dev, int param_id, u64 *pval)
36 {
37 size_t psize;
38 u64 *p;
39
40 p = dfh_find_param(dfl_dev, param_id, &psize);
41 if (IS_ERR(p))
42 return PTR_ERR(p);
43
44 if (psize != sizeof(*pval))
45 return -EINVAL;
46
47 *pval = *p;
48
49 return 0;
50 }
51
dfl_uart_get_params(struct dfl_device * dfl_dev,struct uart_8250_port * uart)52 static int dfl_uart_get_params(struct dfl_device *dfl_dev, struct uart_8250_port *uart)
53 {
54 struct device *dev = &dfl_dev->dev;
55 u64 fifo_len, clk_freq, reg_layout;
56 u32 reg_width;
57 int ret;
58
59 ret = dfh_get_u64_param_val(dfl_dev, DFHv1_PARAM_ID_CLK_FRQ, &clk_freq);
60 if (ret)
61 return dev_err_probe(dev, ret, "missing CLK_FRQ param\n");
62
63 uart->port.uartclk = clk_freq;
64
65 ret = dfh_get_u64_param_val(dfl_dev, DFHv1_PARAM_ID_FIFO_LEN, &fifo_len);
66 if (ret)
67 return dev_err_probe(dev, ret, "missing FIFO_LEN param\n");
68
69 switch (fifo_len) {
70 case 32:
71 uart->port.type = PORT_ALTR_16550_F32;
72 break;
73
74 case 64:
75 uart->port.type = PORT_ALTR_16550_F64;
76 break;
77
78 case 128:
79 uart->port.type = PORT_ALTR_16550_F128;
80 break;
81
82 default:
83 return dev_err_probe(dev, -EINVAL, "unsupported FIFO_LEN %llu\n", fifo_len);
84 }
85
86 ret = dfh_get_u64_param_val(dfl_dev, DFHv1_PARAM_ID_REG_LAYOUT, ®_layout);
87 if (ret)
88 return dev_err_probe(dev, ret, "missing REG_LAYOUT param\n");
89
90 uart->port.regshift = FIELD_GET(DFHv1_PARAM_REG_LAYOUT_SHIFT, reg_layout);
91 reg_width = FIELD_GET(DFHv1_PARAM_REG_LAYOUT_WIDTH, reg_layout);
92 switch (reg_width) {
93 case 4:
94 uart->port.iotype = UPIO_MEM32;
95 break;
96
97 case 2:
98 uart->port.iotype = UPIO_MEM16;
99 break;
100
101 default:
102 return dev_err_probe(dev, -EINVAL, "unsupported reg-width %u\n", reg_width);
103
104 }
105
106 return 0;
107 }
108
dfl_uart_probe(struct dfl_device * dfl_dev)109 static int dfl_uart_probe(struct dfl_device *dfl_dev)
110 {
111 struct device *dev = &dfl_dev->dev;
112 struct uart_8250_port uart = { };
113 struct dfl_uart *dfluart;
114 int ret;
115
116 uart.port.flags = UPF_IOREMAP;
117 uart.port.mapbase = dfl_dev->mmio_res.start;
118 uart.port.mapsize = resource_size(&dfl_dev->mmio_res);
119
120 ret = dfl_uart_get_params(dfl_dev, &uart);
121 if (ret < 0)
122 return dev_err_probe(dev, ret, "failed uart feature walk\n");
123
124 if (dfl_dev->num_irqs == 1)
125 uart.port.irq = dfl_dev->irqs[0];
126
127 dfluart = devm_kzalloc(dev, sizeof(*dfluart), GFP_KERNEL);
128 if (!dfluart)
129 return -ENOMEM;
130
131 dfluart->line = serial8250_register_8250_port(&uart);
132 if (dfluart->line < 0)
133 return dev_err_probe(dev, dfluart->line, "unable to register 8250 port.\n");
134
135 dev_set_drvdata(dev, dfluart);
136
137 return 0;
138 }
139
dfl_uart_remove(struct dfl_device * dfl_dev)140 static void dfl_uart_remove(struct dfl_device *dfl_dev)
141 {
142 struct dfl_uart *dfluart = dev_get_drvdata(&dfl_dev->dev);
143
144 serial8250_unregister_port(dfluart->line);
145 }
146
147 #define FME_FEATURE_ID_UART 0x24
148
149 static const struct dfl_device_id dfl_uart_ids[] = {
150 { FME_ID, FME_FEATURE_ID_UART },
151 { }
152 };
153 MODULE_DEVICE_TABLE(dfl, dfl_uart_ids);
154
155 static struct dfl_driver dfl_uart_driver = {
156 .drv = {
157 .name = "dfl-uart",
158 },
159 .id_table = dfl_uart_ids,
160 .probe = dfl_uart_probe,
161 .remove = dfl_uart_remove,
162 };
163 module_dfl_driver(dfl_uart_driver);
164
165 MODULE_DESCRIPTION("DFL Intel UART driver");
166 MODULE_AUTHOR("Intel Corporation");
167 MODULE_LICENSE("GPL");
168