diff options
Diffstat (limited to 'drivers/tty/serial/8250/8250_dw.c')
-rw-r--r-- | drivers/tty/serial/8250/8250_dw.c | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c new file mode 100644 index 000000000000..f574eef3075f --- /dev/null +++ b/drivers/tty/serial/8250/8250_dw.c | |||
@@ -0,0 +1,184 @@ | |||
1 | /* | ||
2 | * Synopsys DesignWare 8250 driver. | ||
3 | * | ||
4 | * Copyright 2011 Picochip, Jamie Iles. | ||
5 | * | ||
6 | * This program is free software; you can redistribute it and/or modify | ||
7 | * it under the terms of the GNU General Public License as published by | ||
8 | * the Free Software Foundation; either version 2 of the License, or | ||
9 | * (at your option) any later version. | ||
10 | * | ||
11 | * The Synopsys DesignWare 8250 has an extra feature whereby it detects if the | ||
12 | * LCR is written whilst busy. If it is, then a busy detect interrupt is | ||
13 | * raised, the LCR needs to be rewritten and the uart status register read. | ||
14 | */ | ||
15 | #include <linux/device.h> | ||
16 | #include <linux/init.h> | ||
17 | #include <linux/io.h> | ||
18 | #include <linux/module.h> | ||
19 | #include <linux/serial_8250.h> | ||
20 | #include <linux/serial_core.h> | ||
21 | #include <linux/serial_reg.h> | ||
22 | #include <linux/of.h> | ||
23 | #include <linux/of_irq.h> | ||
24 | #include <linux/of_platform.h> | ||
25 | #include <linux/platform_device.h> | ||
26 | #include <linux/slab.h> | ||
27 | |||
28 | struct dw8250_data { | ||
29 | int last_lcr; | ||
30 | int line; | ||
31 | }; | ||
32 | |||
33 | static void dw8250_serial_out(struct uart_port *p, int offset, int value) | ||
34 | { | ||
35 | struct dw8250_data *d = p->private_data; | ||
36 | |||
37 | if (offset == UART_LCR) | ||
38 | d->last_lcr = value; | ||
39 | |||
40 | offset <<= p->regshift; | ||
41 | writeb(value, p->membase + offset); | ||
42 | } | ||
43 | |||
44 | static unsigned int dw8250_serial_in(struct uart_port *p, int offset) | ||
45 | { | ||
46 | offset <<= p->regshift; | ||
47 | |||
48 | return readb(p->membase + offset); | ||
49 | } | ||
50 | |||
51 | static void dw8250_serial_out32(struct uart_port *p, int offset, int value) | ||
52 | { | ||
53 | struct dw8250_data *d = p->private_data; | ||
54 | |||
55 | if (offset == UART_LCR) | ||
56 | d->last_lcr = value; | ||
57 | |||
58 | offset <<= p->regshift; | ||
59 | writel(value, p->membase + offset); | ||
60 | } | ||
61 | |||
62 | static unsigned int dw8250_serial_in32(struct uart_port *p, int offset) | ||
63 | { | ||
64 | offset <<= p->regshift; | ||
65 | |||
66 | return readl(p->membase + offset); | ||
67 | } | ||
68 | |||
69 | /* Offset for the DesignWare's UART Status Register. */ | ||
70 | #define UART_USR 0x1f | ||
71 | |||
72 | static int dw8250_handle_irq(struct uart_port *p) | ||
73 | { | ||
74 | struct dw8250_data *d = p->private_data; | ||
75 | unsigned int iir = p->serial_in(p, UART_IIR); | ||
76 | |||
77 | if (serial8250_handle_irq(p, iir)) { | ||
78 | return 1; | ||
79 | } else if ((iir & UART_IIR_BUSY) == UART_IIR_BUSY) { | ||
80 | /* Clear the USR and write the LCR again. */ | ||
81 | (void)p->serial_in(p, UART_USR); | ||
82 | p->serial_out(p, d->last_lcr, UART_LCR); | ||
83 | |||
84 | return 1; | ||
85 | } | ||
86 | |||
87 | return 0; | ||
88 | } | ||
89 | |||
90 | static int __devinit dw8250_probe(struct platform_device *pdev) | ||
91 | { | ||
92 | struct uart_port port = {}; | ||
93 | struct resource *regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); | ||
94 | struct resource *irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0); | ||
95 | struct device_node *np = pdev->dev.of_node; | ||
96 | u32 val; | ||
97 | struct dw8250_data *data; | ||
98 | |||
99 | if (!regs || !irq) { | ||
100 | dev_err(&pdev->dev, "no registers/irq defined\n"); | ||
101 | return -EINVAL; | ||
102 | } | ||
103 | |||
104 | data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); | ||
105 | if (!data) | ||
106 | return -ENOMEM; | ||
107 | port.private_data = data; | ||
108 | |||
109 | spin_lock_init(&port.lock); | ||
110 | port.mapbase = regs->start; | ||
111 | port.irq = irq->start; | ||
112 | port.handle_irq = dw8250_handle_irq; | ||
113 | port.type = PORT_8250; | ||
114 | port.flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP | | ||
115 | UPF_FIXED_PORT | UPF_FIXED_TYPE; | ||
116 | port.dev = &pdev->dev; | ||
117 | |||
118 | port.iotype = UPIO_MEM; | ||
119 | port.serial_in = dw8250_serial_in; | ||
120 | port.serial_out = dw8250_serial_out; | ||
121 | if (!of_property_read_u32(np, "reg-io-width", &val)) { | ||
122 | switch (val) { | ||
123 | case 1: | ||
124 | break; | ||
125 | case 4: | ||
126 | port.iotype = UPIO_MEM32; | ||
127 | port.serial_in = dw8250_serial_in32; | ||
128 | port.serial_out = dw8250_serial_out32; | ||
129 | break; | ||
130 | default: | ||
131 | dev_err(&pdev->dev, "unsupported reg-io-width (%u)\n", | ||
132 | val); | ||
133 | return -EINVAL; | ||
134 | } | ||
135 | } | ||
136 | |||
137 | if (!of_property_read_u32(np, "reg-shift", &val)) | ||
138 | port.regshift = val; | ||
139 | |||
140 | if (of_property_read_u32(np, "clock-frequency", &val)) { | ||
141 | dev_err(&pdev->dev, "no clock-frequency property set\n"); | ||
142 | return -EINVAL; | ||
143 | } | ||
144 | port.uartclk = val; | ||
145 | |||
146 | data->line = serial8250_register_port(&port); | ||
147 | if (data->line < 0) | ||
148 | return data->line; | ||
149 | |||
150 | platform_set_drvdata(pdev, data); | ||
151 | |||
152 | return 0; | ||
153 | } | ||
154 | |||
155 | static int __devexit dw8250_remove(struct platform_device *pdev) | ||
156 | { | ||
157 | struct dw8250_data *data = platform_get_drvdata(pdev); | ||
158 | |||
159 | serial8250_unregister_port(data->line); | ||
160 | |||
161 | return 0; | ||
162 | } | ||
163 | |||
164 | static const struct of_device_id dw8250_match[] = { | ||
165 | { .compatible = "snps,dw-apb-uart" }, | ||
166 | { /* Sentinel */ } | ||
167 | }; | ||
168 | MODULE_DEVICE_TABLE(of, dw8250_match); | ||
169 | |||
170 | static struct platform_driver dw8250_platform_driver = { | ||
171 | .driver = { | ||
172 | .name = "dw-apb-uart", | ||
173 | .owner = THIS_MODULE, | ||
174 | .of_match_table = dw8250_match, | ||
175 | }, | ||
176 | .probe = dw8250_probe, | ||
177 | .remove = __devexit_p(dw8250_remove), | ||
178 | }; | ||
179 | |||
180 | module_platform_driver(dw8250_platform_driver); | ||
181 | |||
182 | MODULE_AUTHOR("Jamie Iles"); | ||
183 | MODULE_LICENSE("GPL"); | ||
184 | MODULE_DESCRIPTION("Synopsys DesignWare 8250 serial port driver"); | ||