From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.free-electrons.com ([62.4.15.54]) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1dChvn-0001J2-To for linux-mtd@lists.infradead.org; Mon, 22 May 2017 07:39:10 +0000 Date: Mon, 22 May 2017 09:38:35 +0200 From: Boris Brezillon To: Chris Packham Cc: "dwmw2@infradead.org" , "computersforpeace@gmail.com" , "andrew@lunn.ch" , "linux-mtd@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Marek Vasut , Richard Weinberger , Cyrille Pitchen Subject: Re: [PATCH 3/4] mtd: mchp23k256: add partitioning support Message-ID: <20170522093835.70f7f110@bbrezillon> In-Reply-To: <31c94577108c42c1b51d410081d97eb5@svr-chch-ex1.atlnz.lc> References: <20170517053908.26138-1-chris.packham@alliedtelesis.co.nz> <20170517053908.26138-4-chris.packham@alliedtelesis.co.nz> <20170517172911.5f926712@bbrezillon> <31c94577108c42c1b51d410081d97eb5@svr-chch-ex1.atlnz.lc> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi Chris, On Mon, 22 May 2017 04:52:34 +0000 Chris Packham wrote: > On 18/05/17 03:29, Boris Brezillon wrote: > > Hi Chris, > > > > On Wed, 17 May 2017 17:39:07 +1200 > > Chris Packham wrote: > > > >> Setting the of_node for the mtd device allows the generic mtd code to > >> setup the partitions. Additionally we must specify a non-zero erasesize > >> for the partitions to be writeable. > >> > >> Signed-off-by: Chris Packham > >> --- > >> drivers/mtd/devices/mchp23k256.c | 5 +++++ > >> 1 file changed, 5 insertions(+) > >> > >> diff --git a/drivers/mtd/devices/mchp23k256.c b/drivers/mtd/devices/mchp23k256.c > >> index 2542f5b8b63f..02c6b9dcbd3e 100644 > >> --- a/drivers/mtd/devices/mchp23k256.c > >> +++ b/drivers/mtd/devices/mchp23k256.c > >> @@ -143,6 +143,7 @@ static int mchp23k256_probe(struct spi_device *spi) > >> > >> data = dev_get_platdata(&spi->dev); > >> > >> + mtd_set_of_node(&flash->mtd, spi->dev.of_node); > >> flash->mtd.dev.parent = &spi->dev; > >> flash->mtd.type = MTD_RAM; > >> flash->mtd.flags = MTD_CAP_RAM; > >> @@ -151,6 +152,10 @@ static int mchp23k256_probe(struct spi_device *spi) > >> flash->mtd._read = mchp23k256_read; > >> flash->mtd._write = mchp23k256_write; > >> > >> + flash->mtd.erasesize = PAGE_SIZE; > >> + while (flash->mtd.size & (flash->mtd.erasesize - 1)) > >> + flash->mtd.erasesize >>= 1; > >> + > > > > Can we fix allocate_partition() to properly handle the > > master->erasesize == 0 case instead of doing that? > > > > Do you mean something like this? I had something slightly different in mind (see below). > > diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c > index ea5e5307f667..0cd20ed6b374 100644 > --- a/drivers/mtd/mtdpart.c > +++ b/drivers/mtd/mtdpart.c > @@ -577,6 +577,7 @@ static struct mtd_part *allocate_partition(struct > mtd_info *master, > part->name); > } > if ((slave->mtd.flags & MTD_WRITEABLE) && > + master->erasesize != 0 && > mtd_mod_by_eb(slave->mtd.size, &slave->mtd)) { > slave->mtd.flags &= ~MTD_WRITEABLE; > > > I'm happy to submit this as a formal patch but it could potentially > affect a number of devices. Whereas the snippet I initially added is > consistent with drivers/mtd/chips/map_ram.c. Well, if you're duplicating a workaround that's a good sign this should actually be handled in the core. > > For now I'll leave v2 as-is but I can send a v3 if needed. > --->8--- diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c index ea5e5307f667..378ff4a9174e 100644 --- a/drivers/mtd/mtdpart.c +++ b/drivers/mtd/mtdpart.c @@ -393,7 +393,9 @@ 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->erasesize ? : master->writesize; struct mtd_part *slave; + u32 remainder; char *name; /* allocate the partition structure */ @@ -499,10 +501,12 @@ 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) { + u64 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 +571,22 @@ 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); }