1// SPDX-License-Identifier: GPL-2.0
2/*
3 * SDK7786 FPGA SRAM Support.
4 *
5 * Copyright (C) 2010  Paul Mundt
6 */
7#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8
9#include <linux/init.h>
10#include <linux/kernel.h>
11#include <linux/types.h>
12#include <linux/io.h>
13#include <linux/string.h>
14#include <mach/fpga.h>
15#include <asm/sram.h>
16#include <linux/sizes.h>
17
18static int __init fpga_sram_init(void)
19{
20	unsigned long phys;
21	unsigned int area;
22	void __iomem *vaddr;
23	int ret;
24	u16 data;
25
26	/* Enable FPGA SRAM */
27	data = fpga_read_reg(LCLASR);
28	data |= LCLASR_FRAMEN;
29	fpga_write_reg(data, LCLASR);
30
31	/*
32	 * FPGA_SEL determines the area mapping
33	 */
34	area = (data & LCLASR_FPGA_SEL_MASK) >> LCLASR_FPGA_SEL_SHIFT;
35	if (unlikely(area == LCLASR_AREA_MASK)) {
36		pr_err("FPGA memory unmapped.\n");
37		return -ENXIO;
38	}
39
40	/*
41	 * The memory itself occupies a 2KiB range at the top of the area
42	 * immediately below the system registers.
43	 */
44	phys = (area << 26) + SZ_64M - SZ_4K;
45
46	/*
47	 * The FPGA SRAM resides in translatable physical space, so set
48	 * up a mapping prior to inserting it in to the pool.
49	 */
50	vaddr = ioremap(phys, SZ_2K);
51	if (unlikely(!vaddr)) {
52		pr_err("Failed remapping FPGA memory.\n");
53		return -ENXIO;
54	}
55
56	pr_info("Adding %dKiB of FPGA memory at 0x%08lx-0x%08lx "
57		"(area %d) to pool.\n",
58		SZ_2K >> 10, phys, phys + SZ_2K - 1, area);
59
60	ret = gen_pool_add(sram_pool, (unsigned long)vaddr, SZ_2K, -1);
61	if (unlikely(ret < 0)) {
62		pr_err("Failed adding memory\n");
63		iounmap(vaddr);
64		return ret;
65	}
66
67	return 0;
68}
69postcore_initcall(fpga_sram_init);
70