Hi Jagan, > -----Original Message----- > From: Jagan Teki [mailto:jagannadh.t...@gmail.com] > Sent: Wednesday, May 09, 2018 1:22 PM > To: Siva Durga Prasad Paladugu <siva...@xilinx.com> > Cc: Jagan Teki <ja...@amarulasolutions.com>; U-Boot-Denx <u- > b...@lists.denx.de>; michal.si...@xilinx.com > Subject: Re: [U-Boot] [PATCH v3 1/2] spi: zynqmp_gqspi: Add support for > ZynqMP qspi driver > > On Wed, May 9, 2018 at 1:20 PM, Siva Durga Prasad Paladugu > <siva...@xilinx.com> wrote: > > > > Hi, > > > >> -----Original Message----- > >> From: Jagan Teki [mailto:jagannadh.t...@gmail.com] > >> Sent: Wednesday, May 09, 2018 1:12 PM > >> To: Siva Durga Prasad Paladugu <siva...@xilinx.com> > >> Cc: Jagan Teki <ja...@amarulasolutions.com>; U-Boot-Denx <u- > >> b...@lists.denx.de>; michal.si...@xilinx.com > >> Subject: Re: [U-Boot] [PATCH v3 1/2] spi: zynqmp_gqspi: Add support > >> for ZynqMP qspi driver > >> > >> On Wed, May 9, 2018 at 12:33 PM, Siva Durga Prasad Paladugu > >> <siva...@xilinx.com> wrote: > >> > Hi Jagan, > >> > > >> >> -----Original Message----- > >> >> From: Jagan Teki [mailto:ja...@amarulasolutions.com] > >> >> Sent: Wednesday, May 09, 2018 12:01 PM > >> >> To: Siva Durga Prasad Paladugu <siva...@xilinx.com> > >> >> Cc: U-Boot-Denx <u-boot@lists.denx.de>; michal.si...@xilinx.com > >> >> Subject: Re: [PATCH v3 1/2] spi: zynqmp_gqspi: Add support for > >> ZynqMP > >> >> qspi driver > >> >> > >> >> On Tue, May 8, 2018 at 3:43 PM, Siva Durga Prasad Paladugu > >> >> <siva.durga.palad...@xilinx.com> wrote: > >> >> > This patch adds qspi driver support for ZynqMP SoC. This driver > >> >> > is responsible for communicating with qspi flash devices. > >> >> > > >> >> > Signed-off-by: Siva Durga Prasad Paladugu > >> >> > <siva.durga.palad...@xilinx.com> > >> >> > --- > >> >> > Changes for v3: > >> >> > - Renamed all macros, functions, files and configs as per > >> >> > comment > >> >> > - Used wait_for_bit wherever required > >> >> > - Removed unnecessary header inclusion > >> >> > > >> >> > Changes for v2: > >> >> > - Rebased on top of latest master > >> >> > - Moved macro definitions to .h file as per comment > >> >> > - Fixed magic values with macros as per comment > >> >> > --- > >> >> > arch/arm/include/asm/arch-zynqmp/zynqmp_gqspi.h | 154 > ++++++ > >> >> > drivers/spi/Kconfig | 7 + > >> >> > drivers/spi/Makefile | 1 + > >> >> > drivers/spi/zynqmp_gqspi.c | 670 > >> >> ++++++++++++++++++++++++ > >> >> > 4 files changed, 832 insertions(+) create mode 100644 > >> >> > arch/arm/include/asm/arch- > >> >> zynqmp/zynqmp_gqspi.h > >> >> > create mode 100644 drivers/spi/zynqmp_gqspi.c > >> >> > > >> >> > diff --git a/arch/arm/include/asm/arch-zynqmp/zynqmp_gqspi.h > >> >> > b/arch/arm/include/asm/arch-zynqmp/zynqmp_gqspi.h > >> >> > >> >> already asked you to move this header code in driver .c file > >> > > >> > You might have missed my reply to your earlier comment on this. > >> > These were moved to .h based on comment from Lukasz in v1. > >> > I don’t have any issue in having them anywhere. Let me know your > choice. > >> > >> I'm trying to align Linux code, better to move like that and make > >> sure to use similar macros. > >> > >> > > > > > [snip] > > > >> >> > +static void zynqmp_qspi_genfifo_cmd(struct zynqmp_qspi_priv > >> *priv) { > >> >> > + u8 command = 1; > >> >> > + u32 gen_fifo_cmd; > >> >> > + u32 bytecount = 0; > >> >> > + > >> >> > + while (priv->len) { > >> >> > + gen_fifo_cmd = zynqmp_qspi_bus_select(priv); > >> >> > + gen_fifo_cmd |= GQSPI_GFIFO_TX; > >> >> > + > >> >> > + if (command) { > >> >> > + command = 0; > >> >> > + last_cmd = *(u8 *)priv->tx_buf; > >> >> > + } > >> >> > >> >> don't understand this code can you explain? command assigned 1 it > >> >> will not updated anywhere? > >> > > >> > I want to store last command sent. As the first byte in loop only > >> > contains command, it ensures it fills only for one time and next > >> > time it > >> may contain data to be sent along with command. > >> > Command initialized to 1 while declaring it above(u8 command = 1). > >> > >> Ok the first TX buf has command and reused in tx and rx fifo, how > >> come to use use same in rx fifo? why is is last_cmd it is first_cmd? > > > > This holds the command that was sent last to the device before we use in > tx/rx fill, hence used this name. > > ie. what I wonder, usually the spi transfer start with cmd + data in that case > it would be the first command, did gqspi work reverse way?
It's also same as others :-), the last_cmd holds the recent command that was sent to the device. Its just name. To avoid confusion, I can use other names like "cmd_sent or cmd_recent". Hope this is ok for you or suggest which one would be appropriate. Thanks, Siva > > Jagan. _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
