1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * mach-davinci/sram.c - DaVinci simple SRAM allocator
4 *
5 * Copyright (C) 2009 David Brownell
6 */
7 #include <linux/module.h>
8 #include <linux/init.h>
9 #include <linux/io.h>
10 #include <linux/genalloc.h>
11
12 #include "common.h"
13 #include "sram.h"
14
15 static struct gen_pool *sram_pool;
16
sram_get_gen_pool(void)17 struct gen_pool *sram_get_gen_pool(void)
18 {
19 return sram_pool;
20 }
21
sram_alloc(size_t len,dma_addr_t * dma)22 void *sram_alloc(size_t len, dma_addr_t *dma)
23 {
24 dma_addr_t dma_base = davinci_soc_info.sram_dma;
25
26 if (dma)
27 *dma = 0;
28 if (!sram_pool || (dma && !dma_base))
29 return NULL;
30
31 return gen_pool_dma_alloc(sram_pool, len, dma);
32
33 }
34 EXPORT_SYMBOL(sram_alloc);
35
sram_free(void * addr,size_t len)36 void sram_free(void *addr, size_t len)
37 {
38 gen_pool_free(sram_pool, (unsigned long) addr, len);
39 }
40 EXPORT_SYMBOL(sram_free);
41
42
43 /*
44 * REVISIT This supports CPU and DMA access to/from SRAM, but it
45 * doesn't (yet?) support some other notable uses of SRAM: as TCM
46 * for data and/or instructions; and holding code needed to enter
47 * and exit suspend states (while DRAM can't be used).
48 */
sram_init(void)49 static int __init sram_init(void)
50 {
51 phys_addr_t phys = davinci_soc_info.sram_dma;
52 unsigned len = davinci_soc_info.sram_len;
53 int status = 0;
54 void __iomem *addr;
55
56 if (len) {
57 len = min_t(unsigned, len, SRAM_SIZE);
58 sram_pool = gen_pool_create(ilog2(SRAM_GRANULARITY), -1);
59 if (!sram_pool)
60 status = -ENOMEM;
61 }
62
63 if (sram_pool) {
64 addr = ioremap(phys, len);
65 if (!addr)
66 return -ENOMEM;
67 status = gen_pool_add_virt(sram_pool, (unsigned long) addr,
68 phys, len, -1);
69 if (status < 0)
70 iounmap(addr);
71 }
72
73 WARN_ON(status < 0);
74 return status;
75 }
76 core_initcall(sram_init);
77
78