From patchwork Mon Oct 8 15:25:52 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: [RFC] mtd/uclinux: support ROM and allow passing the base address Date: Mon, 08 Oct 2012 05:25:52 -0000 From: =?utf-8?q?Uwe_Kleine-K=C3=B6nig_=3Cu=2Ekleine-koenig=40pengutronix=2E?= =?utf-8?b?ZGU+?= X-Patchwork-Id: 190050 Message-Id: <1349709952-4332-1-git-send-email-u.kleine-koenig@pengutronix.de> To: linux-mtd@lists.infradead.org Cc: Artem Bityutskiy , kernel@pengutronix.de, Greg Ungerer This allows to put the filesystem at a defined address in ROM allowing to save more precious RAM. I think it's save to default to ROM because the intention of using the uclinux map is to use a romfs and so mtd-ram doesn't give you anything that mtd-rom doesn't. Signed-off-by: Uwe Kleine-König Acked-by: Greg Ungerer --- drivers/mtd/maps/Kconfig | 2 +- drivers/mtd/maps/uclinux.c | 30 +++++++++++++++++++++++------- 2 files changed, 24 insertions(+), 8 deletions(-) diff --git a/drivers/mtd/maps/Kconfig b/drivers/mtd/maps/Kconfig index 5ba2458..d945950 100644 --- a/drivers/mtd/maps/Kconfig +++ b/drivers/mtd/maps/Kconfig @@ -443,7 +443,7 @@ config MTD_GPIO_ADDR config MTD_UCLINUX bool "Generic uClinux RAM/ROM filesystem support" - depends on MTD_RAM=y && !MMU + depends on (MTD_RAM=y || MTD_ROM=y) && !MMU help Map driver to support image based filesystems for uClinux. diff --git a/drivers/mtd/maps/uclinux.c b/drivers/mtd/maps/uclinux.c index c3bb304..a8a5929 100644 --- a/drivers/mtd/maps/uclinux.c +++ b/drivers/mtd/maps/uclinux.c @@ -23,12 +23,13 @@ /****************************************************************************/ -struct map_info uclinux_ram_map = { - .name = "RAM", - .phys = (unsigned long)__bss_stop, +static struct map_info uclinux_ram_map = { .size = 0, }; +static unsigned long physaddr = -1; +module_param(physaddr, ulong, S_IRUGO); + static struct mtd_info *uclinux_ram_mtdinfo; /****************************************************************************/ @@ -60,11 +61,17 @@ static int __init uclinux_mtd_init(void) struct map_info *mapp; mapp = &uclinux_ram_map; + + if (physaddr == -1) + mapp->phys = (resource_size_t)__bss_stop; + else + mapp->phys = physaddr; + if (!mapp->size) mapp->size = PAGE_ALIGN(ntohl(*((unsigned long *)(mapp->phys + 8)))); mapp->bankwidth = 4; - printk("uclinux[mtd]: RAM probe address=0x%x size=0x%x\n", + printk("uclinux[mtd]: RAM/ROM probe address=0x%x size=0x%x\n", (int) mapp->phys, (int) mapp->size); mapp->virt = ioremap_nocache(mapp->phys, mapp->size); @@ -76,9 +83,18 @@ static int __init uclinux_mtd_init(void) simple_map_init(mapp); - mtd = do_map_probe("map_ram", mapp); + mapp->name = "ROM"; + mtd = do_map_probe("map_rom", mapp); + if (!mtd) { + /* fall back to ram probing for compatibility reasons */ + mapp->name = "RAM"; + mtd = do_map_probe("map_ram", mapp); + if (mtd && IS_ENABLED(CONFIG_MTD_ROM)) + pr_err("Failed to map rom, but ram succeeded. Please report this issue!\n"); + } + if (!mtd) { - printk("uclinux[mtd]: failed to find a mapping?\n"); + printk("uclinux[mtd]: failed to find a rom/ram mapping?\n"); iounmap(mapp->virt); return(-ENXIO); } @@ -115,6 +131,6 @@ module_exit(uclinux_mtd_cleanup); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Greg Ungerer "); -MODULE_DESCRIPTION("Generic RAM based MTD for uClinux"); +MODULE_DESCRIPTION("Generic RAM/ROM based MTD for uClinux"); /****************************************************************************/