1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * SDK7786 FPGA Support.
4  *
5  * Copyright (C) 2010  Paul Mundt
6  */
7 #include <linux/init.h>
8 #include <linux/io.h>
9 #include <linux/bcd.h>
10 #include <mach/fpga.h>
11 #include <linux/sizes.h>
12 
13 #define FPGA_REGS_OFFSET	0x03fff800
14 #define FPGA_REGS_SIZE		0x490
15 
16 /*
17  * The FPGA can be mapped in any of the generally available areas,
18  * so we attempt to scan for it using the fixed SRSTR read magic.
19  *
20  * Once the FPGA is located, the rest of the mapping data for the other
21  * components can be determined dynamically from its section mapping
22  * registers.
23  */
sdk7786_fpga_probe(void)24 static void __iomem *sdk7786_fpga_probe(void)
25 {
26 	unsigned long area;
27 	void __iomem *base;
28 
29 	/*
30 	 * Iterate over all of the areas where the FPGA could be mapped.
31 	 * The possible range is anywhere from area 0 through 6, area 7
32 	 * is reserved.
33 	 */
34 	for (area = PA_AREA0; area < PA_AREA7; area += SZ_64M) {
35 		base = ioremap(area + FPGA_REGS_OFFSET, FPGA_REGS_SIZE);
36 		if (!base) {
37 			/* Failed to remap this area, move along. */
38 			continue;
39 		}
40 
41 		if (ioread16(base + SRSTR) == SRSTR_MAGIC)
42 			return base;	/* Found it! */
43 
44 		iounmap(base);
45 	}
46 
47 	return NULL;
48 }
49 
50 void __iomem *sdk7786_fpga_base;
51 
sdk7786_fpga_init(void)52 void __init sdk7786_fpga_init(void)
53 {
54 	u16 version, date;
55 
56 	sdk7786_fpga_base = sdk7786_fpga_probe();
57 	if (unlikely(!sdk7786_fpga_base)) {
58 		panic("FPGA detection failed.\n");
59 		return;
60 	}
61 
62 	version = fpga_read_reg(FPGAVR);
63 	date = fpga_read_reg(FPGADR);
64 
65 	pr_info("\tFPGA version:\t%d.%d (built on %d/%d/%d)\n",
66 		bcd2bin(version >> 8) & 0xf, bcd2bin(version & 0xf),
67 		((date >> 12) & 0xf) + 2000,
68 		(date >> 8) & 0xf, bcd2bin(date & 0xff));
69 }
70