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
18 static 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 }
69 postcore_initcall(fpga_sram_init);
70
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