Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751598AbdFID6i (ORCPT ); Thu, 8 Jun 2017 23:58:38 -0400 Received: from gate2.alliedtelesis.co.nz ([202.36.163.20]:57387 "EHLO gate2.alliedtelesis.co.nz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751483AbdFID6h (ORCPT ); Thu, 8 Jun 2017 23:58:37 -0400 From: Chris Packham To: computersforpeace@gmail.com, boris.brezillon@free-electrons.com, linux-mtd@lists.infradead.org Cc: linux-kernel@vger.kernel.org, andrew@lunn.ch, Chris Packham , David Woodhouse , Marek Vasut , Richard Weinberger , Cyrille Pitchen Subject: [PATCH v6] mtd: handle partitioning on devices with 0 erasesize Date: Fri, 9 Jun 2017 15:58:31 +1200 Message-Id: <20170609035831.6258-1-chris.packham@alliedtelesis.co.nz> X-Mailer: git-send-email 2.13.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3420 Lines: 86 erasesize is meaningful for flash devices but for SRAM there is no concept of an erase block so erasesize is set to 0. When partitioning these devices instead of ensuring partitions fall on erasesize boundaries we ensure they fall on writesize boundaries. Helped-by: Boris Brezillon Signed-off-by: Chris Packham --- Changes in v3: - new Changes in v4: - None Changes in v5: - None (yet). There is some active discussion on this so it may change. patch 4/5 is somewhat dependent on this but only if partitions are specified on the dt node. Changes in v6: - Use MTD_NO_ERASE flag to decide whether to use writesize or erasesize for alignment purposes drivers/mtd/mtdpart.c | 26 +++++++++++++++++--------- 1 file changed, 17 insertions(+), 9 deletions(-) diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c index ea5e5307f667..2e152e53ace0 100644 --- a/drivers/mtd/mtdpart.c +++ b/drivers/mtd/mtdpart.c @@ -393,8 +393,12 @@ static struct mtd_part *allocate_partition(struct mtd_info *master, const struct mtd_partition *part, int partno, uint64_t cur_offset) { + int wr_alignment = (master->flags & MTD_NO_ERASE) ? master->writesize: + master->erasesize; struct mtd_part *slave; + u32 remainder; char *name; + u64 tmp; /* allocate the partition structure */ slave = kzalloc(sizeof(*slave), GFP_KERNEL); @@ -499,10 +503,11 @@ static struct mtd_part *allocate_partition(struct mtd_info *master, if (slave->offset == MTDPART_OFS_APPEND) slave->offset = cur_offset; if (slave->offset == MTDPART_OFS_NXTBLK) { + tmp = cur_offset; slave->offset = cur_offset; - if (mtd_mod_by_eb(cur_offset, master) != 0) { - /* Round up to next erasesize */ - slave->offset = (mtd_div_by_eb(cur_offset, master) + 1) * master->erasesize; + remainder = do_div(tmp, wr_alignment); + if (remainder) { + slave->offset += wr_alignment - remainder; printk(KERN_NOTICE "Moving partition %d: " "0x%012llx -> 0x%012llx\n", partno, (unsigned long long)cur_offset, (unsigned long long)slave->offset); @@ -567,19 +572,22 @@ static struct mtd_part *allocate_partition(struct mtd_info *master, slave->mtd.erasesize = master->erasesize; } - if ((slave->mtd.flags & MTD_WRITEABLE) && - mtd_mod_by_eb(slave->offset, &slave->mtd)) { + tmp = slave->offset; + remainder = do_div(tmp, wr_alignment); + if ((slave->mtd.flags & MTD_WRITEABLE) && remainder) { /* Doesn't start on a boundary of major erase size */ /* FIXME: Let it be writable if it is on a boundary of * _minor_ erase size though */ slave->mtd.flags &= ~MTD_WRITEABLE; - printk(KERN_WARNING"mtd: partition \"%s\" doesn't start on an erase block boundary -- force read-only\n", + printk(KERN_WARNING"mtd: partition \"%s\" doesn't start on an erase/write block boundary -- force read-only\n", part->name); } - if ((slave->mtd.flags & MTD_WRITEABLE) && - mtd_mod_by_eb(slave->mtd.size, &slave->mtd)) { + + tmp = slave->mtd.size; + remainder = do_div(tmp, wr_alignment); + if ((slave->mtd.flags & MTD_WRITEABLE) && remainder) { slave->mtd.flags &= ~MTD_WRITEABLE; - printk(KERN_WARNING"mtd: partition \"%s\" doesn't end on an erase block -- force read-only\n", + printk(KERN_WARNING"mtd: partition \"%s\" doesn't end on an erase/write block -- force read-only\n", part->name); } -- 2.13.0