Messages in this thread | | | From | Artur Jedrysek <> | Subject | RE: [v2, 2/4] mtd: spi-nor: Add Octal SPI support to Cadence QSPI driver. | Date | Fri, 10 Mar 2017 14:22:11 +0000 |
| |
From: Marek Vasut [mailto:marek.vasut@gmail.com] Sent: 10 marca 2017 15:15
> On 03/10/2017 03:09 PM, Artur Jedrysek wrote: > > CCing Dinh. > > [...] > > >>>>> + /* Determine, whether or not octal transfer MAY be supported */ > >>>> > >>>> But you already know that from DT, no ? > >>>> > >>> > >>> Cadence Octal (formerly Quad) SPI Controller is sold as an IP, and is > >>> configurable. This includes max SPI mode. It is possible to detect, that > >>> Octal SPI controller is configured (during hardware compilation) to support > >>> up to Quad mode, using revision register. > >> > >> So the octal-spi controller always has this config register, but the > >> quad-spi controller may or may not have this register ? > >> > > > > This register was always present. In Quad-SPI, however, it didn't contain > > information about maximum possible mode, as only quad was possible, and > > meaning of bits checked here was different. > > OK > > >>>>> + rev_reg = readl(cqspi->iobase + CQSPI_REG_MODULEID); > >>>>> + dev_info(dev, "CQSPI Module id %x\n", rev_reg); > >>>>> + > >>>>> + switch (rev_reg & CQSPI_REG_MODULEID_CONF_ID_MASK) { > >>>>> + case CQSPI_REG_MODULEID_CONF_ID_OCTAL_PHY: > >>>>> + case CQSPI_REG_MODULEID_CONF_ID_OCTAL: > >>>>> + mode = SPI_NOR_OCTAL; > >>>>> + break; > >>>>> + case CQSPI_REG_MODULEID_CONF_ID_QUAD: > >>>>> + case CQSPI_REG_MODULEID_CONF_ID_QUAD_PHY: > >>>> > >>>> Does this work on all revisions of CQSPI ? > >>>> > >>> > >>> After having a more thorough look at specification of older IP version > >>> (quad only) it seems, that revision register format has indeed changed. > >>> This will be fixed in the next version of the patch. > >> > >> Can the quad-spi controller be configured only as dual or single ? > >> What about the octal one ? These cases should probably be handled > >> somehow too, right ? > >> > > > > Quad-SPI controller can always support single, dual and quad. There was > > no option to configure max mode. Octal-SPI controller can be configured > > to support either octal or quad mode. No controller could be configured > > (during hardware compilation/synthesis) to support only single/dual > > SPI mode. To put it shortly: single, dual and quad is always supported. > > So basically the whole check you need to perform here is > > mode = quad; > if (controller->flags & CAN_DO_OCTAL) { > if (readl(ID_REGISTER) & IS_CONFIGURED_AS_OCTAL) > mode = octal; > } >
Yes. Something similar was already written and tested, and will be sent in the next version of the patch instead.
> -- > Best regards, > Marek Vasut
| |