xref: /optee_os/core/drivers/scif.c (revision a50cb361d9e5735f197ccc87beb0d24af8315369)
1 /*
2  * Copyright (c) 2016, GlobalLogic
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions are met:
7  *
8  * 1. Redistributions of source code must retain the above copyright notice,
9  * this list of conditions and the following disclaimer.
10  *
11  * 2. Redistributions in binary form must reproduce the above copyright notice,
12  * this list of conditions and the following disclaimer in the documentation
13  * and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
16  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
19  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
20  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
21  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
22  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
23  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
24  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
25  * POSSIBILITY OF SUCH DAMAGE.
26  */
27 #include <compiler.h>
28 #include <io.h>
29 #include <util.h>
30 #include <drivers/scif.h>
31 
32 #define SCIF_SCFSR		(0x10)
33 #define SCIF_SCFTDR		(0x0C)
34 #define SCIF_SCFCR		(0x18)
35 #define SCIF_SCFDR		(0x1C)
36 
37 #define SCFSR_TDFE		BIT(5)
38 #define SCFSR_TEND		BIT(6)
39 
40 #define SCFDR_T_SHIFT		8
41 
42 #define SCIF_TX_FIFO_SIZE	16
43 
44 void scif_uart_flush(vaddr_t base)
45 {
46 	while (!(read16(base + SCIF_SCFSR) & SCFSR_TEND))
47 		;
48 }
49 
50 void scif_uart_init(vaddr_t base)
51 {
52 	/* Bootloader should initialize device for us */
53 	scif_uart_flush(base);
54 }
55 
56 void scif_uart_putc(int ch, vaddr_t base)
57 {
58 	/* Wait until there is space in the FIFO */
59 	while ((read16(base + SCIF_SCFDR) >> SCFDR_T_SHIFT) >=
60 		SCIF_TX_FIFO_SIZE)
61 		;
62 	write8(ch, base + SCIF_SCFTDR);
63 	write16(read16(base + SCIF_SCFSR) & ~(SCFSR_TEND | SCFSR_TDFE),
64 		base + SCIF_SCFSR);
65 }
66