xref: /openbmc/linux/arch/sh/boards/mach-sdk7786/fpga.c (revision b2441318)
1 /*
2  * SDK7786 FPGA Support.
3  *
4  * Copyright (C) 2010  Paul Mundt
5  *
6  * This file is subject to the terms and conditions of the GNU General Public
7  * License.  See the file "COPYING" in the main directory of this archive
8  * for more details.
9  */
10 #include <linux/init.h>
11 #include <linux/io.h>
12 #include <linux/bcd.h>
13 #include <mach/fpga.h>
14 #include <asm/sizes.h>
15 
16 #define FPGA_REGS_OFFSET	0x03fff800
17 #define FPGA_REGS_SIZE		0x490
18 
19 /*
20  * The FPGA can be mapped in any of the generally available areas,
21  * so we attempt to scan for it using the fixed SRSTR read magic.
22  *
23  * Once the FPGA is located, the rest of the mapping data for the other
24  * components can be determined dynamically from its section mapping
25  * registers.
26  */
27 static void __iomem *sdk7786_fpga_probe(void)
28 {
29 	unsigned long area;
30 	void __iomem *base;
31 
32 	/*
33 	 * Iterate over all of the areas where the FPGA could be mapped.
34 	 * The possible range is anywhere from area 0 through 6, area 7
35 	 * is reserved.
36 	 */
37 	for (area = PA_AREA0; area < PA_AREA7; area += SZ_64M) {
38 		base = ioremap_nocache(area + FPGA_REGS_OFFSET, FPGA_REGS_SIZE);
39 		if (!base) {
40 			/* Failed to remap this area, move along. */
41 			continue;
42 		}
43 
44 		if (ioread16(base + SRSTR) == SRSTR_MAGIC)
45 			return base;	/* Found it! */
46 
47 		iounmap(base);
48 	}
49 
50 	return NULL;
51 }
52 
53 void __iomem *sdk7786_fpga_base;
54 
55 void __init sdk7786_fpga_init(void)
56 {
57 	u16 version, date;
58 
59 	sdk7786_fpga_base = sdk7786_fpga_probe();
60 	if (unlikely(!sdk7786_fpga_base)) {
61 		panic("FPGA detection failed.\n");
62 		return;
63 	}
64 
65 	version = fpga_read_reg(FPGAVR);
66 	date = fpga_read_reg(FPGADR);
67 
68 	pr_info("\tFPGA version:\t%d.%d (built on %d/%d/%d)\n",
69 		bcd2bin(version >> 8) & 0xf, bcd2bin(version & 0xf),
70 		((date >> 12) & 0xf) + 2000,
71 		(date >> 8) & 0xf, bcd2bin(date & 0xff));
72 }
73