aboutsummaryrefslogtreecommitdiffstats
path: root/target/linux/xburst/patches-2.6.34/103-serial.patch
blob: 162dc627bac3cc6ab27bdcc6b4f1facf854387e8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
From 6e138e4c3bfa5fb272d215107d85385456281ceb Mon Sep 17 00:00:00 2001
From: Lars-Peter Clausen <lars@metafoo.de>
Date: Sat, 24 Apr 2010 12:19:30 +0200
Subject: [PATCH] Add jz4740 serial driver

---
 drivers/serial/8250.c |  104 ++++++++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 103 insertions(+), 1 deletions(-)

diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index 2b1ea3d..4c41c57 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -200,7 +200,7 @@ static const struct serial8250_config uart_config[] = {
 	[PORT_16550A] = {
 		.name		= "16550A",
 		.fifo_size	= 16,
-		.tx_loadsz	= 16,
+		.tx_loadsz	= 8,
 		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
 		.flags		= UART_CAP_FIFO,
 	},
@@ -407,6 +407,10 @@ static unsigned int mem_serial_in(struct uart_port *p, int offset)
 static void mem_serial_out(struct uart_port *p, int offset, int value)
 {
 	offset = map_8250_out_reg(p, offset) << p->regshift;
+#if defined(CONFIG_JZSOC)
+		if (offset == (UART_FCR << p->regshift))
+			value |= 0x10; /* set FCR.UUE */
+#endif
 	writeb(value, p->membase + offset);
 }
 
@@ -2209,6 +2213,83 @@ static void serial8250_shutdown(struct uart_port *port)
 		serial_unlink_irq_chain(up);
 }
 
+#if defined(CONFIG_JZSOC) && !defined(CONFIG_SOC_JZ4730)
+static unsigned short quot1[3] = {0}; /* quot[0]:baud_div, quot[1]:umr, quot[2]:uacr */
+static unsigned short * serial8250_get_divisor(struct uart_port *port, unsigned int baud)
+{
+	int err, sum, i, j;
+	int a[12], b[12];
+	unsigned short div, umr, uacr;
+	unsigned short umr_best, div_best, uacr_best;
+	long long t0, t1, t2, t3;
+
+	sum = 0;
+	umr_best = div_best = uacr_best = 0;
+	div = 1;
+
+	if ((port->uartclk % (16 * baud)) == 0) {
+		quot1[0] = port->uartclk / (16 * baud);
+		quot1[1] = 16;
+		quot1[2] = 0;
+		return quot1;
+	}
+
+	while (1) {
+		umr = port->uartclk / (baud * div);
+  		if (umr > 32) {
+			div++;
+			continue;
+		}
+		if (umr < 4) {
+			break;
+		}
+		for (i = 0; i < 12; i++) {
+			a[i] = umr;
+			b[i] = 0;
+			sum = 0;
+			for (j = 0; j <= i; j++) {
+				sum += a[j];
+			}
+
+                        /* the precision could be 1/2^(36) due to the value of t0 */
+			t0 = 0x1000000000LL;
+			t1 = (i + 1) * t0;
+			t2 = (sum * div) * t0;
+			t3 = div * t0;
+			do_div(t1, baud);
+			do_div(t2, port->uartclk);
+			do_div(t3, (2 * port->uartclk));
+			err = t1 - t2 - t3;
+
+			if (err > 0) {
+				a[i] += 1;
+				b[i] = 1;
+			}
+		}
+
+		uacr = 0;
+		for (i = 0; i < 12; i++) {
+			if (b[i] == 1) {
+				uacr |= 1 << i;
+			}
+		}
+
+                /* the best value of umr should be near 16, and the value of uacr should better be smaller */
+		if (abs(umr - 16) < abs(umr_best - 16) || (abs(umr - 16) == abs(umr_best - 16) && uacr_best > uacr)) {
+			div_best = div;
+			umr_best = umr;
+			uacr_best = uacr;
+		}
+		div++;
+	}
+
+	quot1[0] = div_best;
+	quot1[1] = umr_best;
+	quot1[2] = uacr_best;
+
+	return quot1;
+}
+#else
 static unsigned int serial8250_get_divisor(struct uart_port *port, unsigned int baud)
 {
 	unsigned int quot;
@@ -2228,6 +2309,7 @@ static unsigned int serial8250_get_divisor(struct uart_port *port, unsigned int
 
 	return quot;
 }
+#endif
 
 static void
 serial8250_set_termios(struct uart_port *port, struct ktermios *termios,
@@ -2237,6 +2319,9 @@ serial8250_set_termios(struct uart_port *port, struct ktermios *termios,
 	unsigned char cval, fcr = 0;
 	unsigned long flags;
 	unsigned int baud, quot;
+#if defined(CONFIG_JZSOC) && !defined(CONFIG_SOC_JZ4730)
+	unsigned short *quot1;
+#endif
 
 	switch (termios->c_cflag & CSIZE) {
 	case CS5:
@@ -2271,7 +2356,12 @@ serial8250_set_termios(struct uart_port *port, struct ktermios *termios,
 	baud = uart_get_baud_rate(port, termios, old,
 				  port->uartclk / 16 / 0xffff,
 				  port->uartclk / 16);
+#if defined(CONFIG_JZSOC) && !defined(CONFIG_SOC_JZ4730)
+	quot1 = serial8250_get_divisor(port, baud);
+	quot = quot1[0]; /* not usefull, just let gcc happy */
+#else
 	quot = serial8250_get_divisor(port, baud);
+#endif
 
 	/*
 	 * Oxford Semi 952 rev B workaround
@@ -2349,6 +2439,10 @@ serial8250_set_termios(struct uart_port *port, struct ktermios *termios,
 	if (up->capabilities & UART_CAP_UUE)
 		up->ier |= UART_IER_UUE | UART_IER_RTOIE;
 
+#ifdef CONFIG_JZSOC
+	up->ier |= UART_IER_RTOIE; /* Set this flag, or very slow */
+#endif
+
 	serial_out(up, UART_IER, up->ier);
 
 	if (up->capabilities & UART_CAP_EFR) {
@@ -2383,7 +2477,15 @@ serial8250_set_termios(struct uart_port *port, struct ktermios *termios,
 		serial_outp(up, UART_LCR, cval | UART_LCR_DLAB);/* set DLAB */
 	}
 
+#if defined(CONFIG_JZSOC) && !defined(CONFIG_SOC_JZ4730)
+#define UART_UMR  9
+#define UART_UACR 10
+	serial_dl_write(up, quot1[0]);
+	serial_outp(up, UART_UMR, quot1[1]);
+	serial_outp(up, UART_UACR, quot1[2]);
+#else
 	serial_dl_write(up, quot);
+#endif
 
 	/*
 	 * LCR DLAB must be set to enable 64-byte FIFO mode. If the FCR
-- 
1.5.6.5