From mboxrd@z Thu Jan 1 00:00:00 1970 From: Heiner Kallweit Subject: Re: fsl-espi, m25p80 and max_transfer_size / max_message_size Date: Mon, 14 Nov 2016 20:06:14 +0100 Message-ID: <158a7129-52ca-79b3-69f9-d6de25483e01@gmail.com> References: <17913d2dea0200f818af5f42a0b2ed42@walle.cc> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: Mark Brown , Michal Suchanek , linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mtd-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Michael Walle , Brian Norris Return-path: In-Reply-To: <17913d2dea0200f818af5f42a0b2ed42-QKn5cuLxLXY@public.gmane.org> Sender: linux-spi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Am 14.11.2016 um 15:22 schrieb Michael Walle: > Hi, > > since commit 02a595d5d6e4 (spi: fsl-espi: eliminate spi nor flash read loop) the fsl-espi is (partly?) broken. Reading 64k from the flash results in the following error: > fsl_espi ffe110000.spi: message too long, size is 65540 bytes > spi_master spi32766: failed to transfer one message from queue > > We are using the m25p80 driver which checks the max_transfer_size. The fsl-espi driver sets the max_message_size to 64k. As far as I understand it, a message can contain multiple transfers. The m25p80 uses two transfers (one 4 byte and one with max_transfer_size, that is 64k) and thus the message has a total length of 65540 bytes which is too long for the driver. > > I didn't find where the max_message_size is checked and I also don't know which part is resposible to handle the correct sizes. The m25p80 driver? Should it use spi_max_message_size() instead of spi_max_transfer_size() ? > Your mail actually doesn't come as a surprise. The patch addressing this scenario is waiting to be applied. See here: https://www.spinics.net/lists/linux-spi/msg08844.html Rgds, Heiner > For example: > --- a/drivers/mtd/devices/m25p80.c > +++ b/drivers/mtd/devices/m25p80.c > @@ -172,7 +172,7 @@ static ssize_t m25p80_read(struct spi_nor *nor, loff_t from, size_t len, > > t[1].rx_buf = buf; > t[1].rx_nbits = m25p80_rx_nbits(nor); > - t[1].len = min(len, spi_max_transfer_size(spi) - t[0].len); > + t[1].len = min(len, spi_max_message_size(spi) - t[0].len); > spi_message_add_tail(&t[1], &m); > > ret = spi_sync(spi, &m); > > -michael > -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html