diff options
| -rw-r--r-- | arch/arm/Kconfig | 1 | ||||
| -rw-r--r-- | arch/arm/mach-davinci/Makefile | 2 | ||||
| -rw-r--r-- | arch/arm/mach-davinci/include/mach/sram.h | 27 | ||||
| -rw-r--r-- | arch/arm/mach-davinci/sram.c | 74 |
4 files changed, 103 insertions, 1 deletions
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 9d02cdb15b23..915b39382e65 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -587,6 +587,7 @@ config ARCH_DAVINCI select ZONE_DMA select HAVE_IDE select COMMON_CLKDEV + select GENERIC_ALLOCATOR help Support for TI's DaVinci platform. diff --git a/arch/arm/mach-davinci/Makefile b/arch/arm/mach-davinci/Makefile index 5b62d8a4b180..059ab78084ba 100644 --- a/arch/arm/mach-davinci/Makefile +++ b/arch/arm/mach-davinci/Makefile @@ -5,7 +5,7 @@ # Common objects obj-y := time.o clock.o serial.o io.o psc.o \ - gpio.o devices.o dma.o usb.o common.o + gpio.o devices.o dma.o usb.o common.o sram.o obj-$(CONFIG_DAVINCI_MUX) += mux.o diff --git a/arch/arm/mach-davinci/include/mach/sram.h b/arch/arm/mach-davinci/include/mach/sram.h new file mode 100644 index 000000000000..111f7cc71e07 --- /dev/null +++ b/arch/arm/mach-davinci/include/mach/sram.h @@ -0,0 +1,27 @@ +/* + * mach/sram.h - DaVinci simple SRAM allocator + * + * Copyright (C) 2009 David Brownell + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ +#ifndef __MACH_SRAM_H +#define __MACH_SRAM_H + +/* ARBITRARY: SRAM allocations are multiples of this 2^N size */ +#define SRAM_GRANULARITY 512 + +/* + * SRAM allocations return a CPU virtual address, or NULL on error. + * If a DMA address is requested and the SRAM supports DMA, its + * mapped address is also returned. + * + * Errors include SRAM memory not being available, and requesting + * DMA mapped SRAM on systems which don't allow that. + */ +extern void *sram_alloc(size_t len, dma_addr_t *dma); +extern void sram_free(void *addr, size_t len); + +#endif /* __MACH_SRAM_H */ diff --git a/arch/arm/mach-davinci/sram.c b/arch/arm/mach-davinci/sram.c new file mode 100644 index 000000000000..db54b2a66b4d --- /dev/null +++ b/arch/arm/mach-davinci/sram.c @@ -0,0 +1,74 @@ +/* + * mach-davinci/sram.c - DaVinci simple SRAM allocator + * + * Copyright (C) 2009 David Brownell + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + */ +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/genalloc.h> + +#include <mach/common.h> +#include <mach/memory.h> +#include <mach/sram.h> + + +static struct gen_pool *sram_pool; + +void *sram_alloc(size_t len, dma_addr_t *dma) +{ + unsigned long vaddr; + dma_addr_t dma_base = davinci_soc_info.sram_dma; + + if (dma) + *dma = 0; + if (!sram_pool || (dma && !dma_base)) + return NULL; + + vaddr = gen_pool_alloc(sram_pool, len); + if (!vaddr) + return NULL; + + if (dma) + *dma = dma_base + (vaddr - SRAM_VIRT); + return (void *)vaddr; + +} +EXPORT_SYMBOL(sram_alloc); + +void sram_free(void *addr, size_t len) +{ + gen_pool_free(sram_pool, (unsigned long) addr, len); +} +EXPORT_SYMBOL(sram_free); + + +/* + * REVISIT This supports CPU and DMA access to/from SRAM, but it + * doesn't (yet?) support some other notable uses of SRAM: as TCM + * for data and/or instructions; and holding code needed to enter + * and exit suspend states (while DRAM can't be used). + */ +static int __init sram_init(void) +{ + unsigned len = davinci_soc_info.sram_len; + int status = 0; + + if (len) { + len = min(len, SRAM_SIZE); + sram_pool = gen_pool_create(ilog2(SRAM_GRANULARITY), -1); + if (!sram_pool) + status = -ENOMEM; + } + if (sram_pool) + status = gen_pool_add(sram_pool, SRAM_VIRT, len, -1); + WARN_ON(status < 0); + return status; +} +core_initcall(sram_init); + |