1 /*
2  * SDK7786 FPGA SRAM 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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11 
12 #include <linux/init.h>
13 #include <linux/kernel.h>
14 #include <linux/types.h>
15 #include <linux/io.h>
16 #include <linux/string.h>
17 #include <mach/fpga.h>
18 #include <asm/sram.h>
19 #include <asm/sizes.h>
20 
fpga_sram_init(void)21 static int __init fpga_sram_init(void)
22 {
23 	unsigned long phys;
24 	unsigned int area;
25 	void __iomem *vaddr;
26 	int ret;
27 	u16 data;
28 
29 	/* Enable FPGA SRAM */
30 	data = fpga_read_reg(LCLASR);
31 	data |= LCLASR_FRAMEN;
32 	fpga_write_reg(data, LCLASR);
33 
34 	/*
35 	 * FPGA_SEL determines the area mapping
36 	 */
37 	area = (data & LCLASR_FPGA_SEL_MASK) >> LCLASR_FPGA_SEL_SHIFT;
38 	if (unlikely(area == LCLASR_AREA_MASK)) {
39 		pr_err("FPGA memory unmapped.\n");
40 		return -ENXIO;
41 	}
42 
43 	/*
44 	 * The memory itself occupies a 2KiB range at the top of the area
45 	 * immediately below the system registers.
46 	 */
47 	phys = (area << 26) + SZ_64M - SZ_4K;
48 
49 	/*
50 	 * The FPGA SRAM resides in translatable physical space, so set
51 	 * up a mapping prior to inserting it in to the pool.
52 	 */
53 	vaddr = ioremap(phys, SZ_2K);
54 	if (unlikely(!vaddr)) {
55 		pr_err("Failed remapping FPGA memory.\n");
56 		return -ENXIO;
57 	}
58 
59 	pr_info("Adding %dKiB of FPGA memory at 0x%08lx-0x%08lx "
60 		"(area %d) to pool.\n",
61 		SZ_2K >> 10, phys, phys + SZ_2K - 1, area);
62 
63 	ret = gen_pool_add(sram_pool, (unsigned long)vaddr, SZ_2K, -1);
64 	if (unlikely(ret < 0)) {
65 		pr_err("Failed adding memory\n");
66 		iounmap(vaddr);
67 		return ret;
68 	}
69 
70 	return 0;
71 }
72 postcore_initcall(fpga_sram_init);
73