From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans-Christian Noren Egtvedt Subject: Re: [PATCH 03/15] dmaengine: dw: rename masters to reflect actual topology Date: Sun, 24 Jan 2016 21:37:21 +0100 Message-ID: <20160124203720.GA29010@samfundet.no> References: <1453663322-14474-1-git-send-email-mans@mansr.com> <1453663322-14474-4-git-send-email-mans@mansr.com> <20160124200959.GA15633@samfundet.no> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Viresh Kumar , Andy Shevchenko , Vinod Koul , linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org, Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Haavard Skinnemoen , Tejun Heo , Dan Williams , Daniel Mack , Haojian Zhuang , Robert Jarzmik , Mark Brown , Greg Kroah-Hartman , Jiri Slaby , devicetree@vger.kernel.org, linux-ide@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-spi@vger.kernel.org, linux-serial@vger.kernel.org To: =?iso-8859-1?Q?M=E5ns_Rullg=E5rd?= Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-ide-owner@vger.kernel.org List-Id: linux-spi.vger.kernel.org Around Sun 24 Jan 2016 20:19:46 +0000 or thereabout, M=E5ns Rullg=E5rd = wrote: > Hans-Christian Noren Egtvedt writes: >> Around Sun 24 Jan 2016 19:21:50 +0000 or thereabout, Mans Rullgard w= rote: >>> From: Andy Shevchenko >>>=20 >>> The source and destination masters are reflecting buses or their la= yers to >>> where the different devices can be connected. The patch changes the= master >>> names to reflect which one is related to which independently on the= transfer >>> direction. >>>=20 >>> The outcome of the change is that the memory data width is now alwa= ys limited >>> by a data width of the master which is dedicated to communicate to = memory. >>>=20 >>> The patch will not break anything since all current users have the = same data >>> width for all masters. Though it would be nice to revisit avr32 pla= forms to >>> check what is the actual hardware topology is used there. It seems = that it has >>> one bus and two masters on it as stated by Table 8-2, that's why ev= erything >>> works independently on the master in use. The purpose of the sequen= tial patch >>> is to fix the driver for configuration of more that one bus. >> >> Not entirely sure what you want to have confirmed here. There are mu= ltiple >> masters and slaves on the HMATRIX internal bus on AVR32, and the DMA >> controller supports up to three simultaneous configurations. >> >> Sounds good to support configuration of more than one bus. I thought= we >> always did support that? Perhaps it was a non-standard avr32 impleme= ntation. >=20 > The DW DMA controller on the AT32AP7000 serves the MCI, AC97, and ABD= AC > peripherals. It appears to work regardless of the values put in the > various master select fields. Perhaps the topology is hardwired in t= he > DMA controller and those fields are ignored. The AVR32 works both > before and after this patch series, the main purpose of which (at lea= st > my patches) is to fix the SATA driver on 460EX. DEST_PER and SRC_PER in the DMA controller selects this, numbers placed= here should match the table you most likely found, 9-3. Wiring the handshake connections is done with the struct dw_dma_slave s= rc_id or dst_id member, depending on data direction. Configured in the at32ap= 700x.c machine code. It is not hard wired on avr32, as there are not one-to-one configuratio= ns and masters. >>> The change is done in the assumption that src_master and dst_master= are >>> reflecting a connection to the memory and peripheral correspondentl= y on all >>> platforms except 460ex. OK, I have no knowledge about the 460ex. >>> Signed-off-by: Andy Shevchenko >>> Signed-off-by: Mans Rullgard >> >> For the avr32 related stuff: >> >> Acked-by: Hans-Christian Egtvedt >> >>> --- >>> Documentation/devicetree/bindings/dma/snps-dma.txt | 4 ++-- >>> arch/avr32/mach-at32ap/at32ap700x.c | 16 ++++++++--= ------ >>> drivers/ata/sata_dwc_460ex.c | 4 ++-- >>> drivers/dma/dw/core.c | 15 +++++++---= ----- >>> drivers/dma/dw/platform.c | 12 ++++++----= -- >>> drivers/dma/dw/regs.h | 4 ++-- >>> drivers/spi/spi-pxa2xx-pci.c | 8 ++++---- >>> drivers/tty/serial/8250/8250_pci.c | 8 ++++---- >>> include/linux/platform_data/dma-dw.h | 8 ++++---- >>> 9 files changed, 39 insertions(+), 40 deletions(-) >> >> --=20 Best regards, Hans-Christian Egtvedt