[U-Boot] [PATCH v3 1/2] spi: zynqmp_gqspi: Add support for ZynqMP qspi driver
Jagan Teki
jagannadh.teki at gmail.com
Wed May 9 11:16:34 UTC 2018
On Wed, May 9, 2018 at 4:44 PM, Siva Durga Prasad Paladugu
<sivadur at xilinx.com> wrote:
> Hi Jagan,
>
>> -----Original Message-----
>> From: Jagan Teki [mailto:jagannadh.teki at gmail.com]
>> Sent: Wednesday, May 09, 2018 4:18 PM
>> To: Siva Durga Prasad Paladugu <sivadur at xilinx.com>
>> Cc: Jagan Teki <jagan at amarulasolutions.com>; U-Boot-Denx <u-
>> boot at lists.denx.de>; michal.simek at 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 4:08 PM, Jagan Teki <jagannadh.teki at gmail.com>
>> wrote:
>> > On Wed, May 9, 2018 at 1:31 PM, Siva Durga Prasad Paladugu
>> > <sivadur at xilinx.com> wrote:
>> >> Hi Jagan,
>> >>
>> >>> -----Original Message-----
>> >>> From: Jagan Teki [mailto:jagannadh.teki at gmail.com]
>> >>> Sent: Wednesday, May 09, 2018 1:22 PM
>> >>> To: Siva Durga Prasad Paladugu <sivadur at xilinx.com>
>> >>> Cc: Jagan Teki <jagan at amarulasolutions.com>; U-Boot-Denx <u-
>> >>> boot at lists.denx.de>; michal.simek at 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
>> >>> <sivadur at xilinx.com> wrote:
>> >>> >
>> >>> > Hi,
>> >>> >
>> >>> >> -----Original Message-----
>> >>> >> From: Jagan Teki [mailto:jagannadh.teki at gmail.com]
>> >>> >> Sent: Wednesday, May 09, 2018 1:12 PM
>> >>> >> To: Siva Durga Prasad Paladugu <sivadur at xilinx.com>
>> >>> >> Cc: Jagan Teki <jagan at amarulasolutions.com>; U-Boot-Denx <u-
>> >>> >> boot at lists.denx.de>; michal.simek at 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
>> >>> >> <sivadur at xilinx.com> wrote:
>> >>> >> > Hi Jagan,
>> >>> >> >
>> >>> >> >> -----Original Message-----
>> >>> >> >> From: Jagan Teki [mailto:jagan at amarulasolutions.com]
>> >>> >> >> Sent: Wednesday, May 09, 2018 12:01 PM
>> >>> >> >> To: Siva Durga Prasad Paladugu <sivadur at xilinx.com>
>> >>> >> >> Cc: U-Boot-Denx <u-boot at lists.denx.de>;
>> >>> >> >> michal.simek at 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.paladugu at 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.paladugu at 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.
>> >
>> > Let's park the naming aside.
>> >
>> > u8 command = 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;
>> > }
>> > ......
>> > priv->len--;
>> > }
>> >
>> > Why the last_cmd assignment is in loop? say priv->len has non-zero the
>> > command is 1 last_cmd assigned and command reassigned to 0 there is
>> no
>> > way execute the if for next while isn't it?
>>
>> The main issue with this driver, which I told/commented several times
>> about using flash specific stuff.
>>
>> +
>> +#define QUAD_OUT_READ_CMD 0x6B
>> +#define QUAD_PAGE_PROGRAM_CMD 0x32
>> +#define DUAL_OUTPUT_FASTRD_CMD 0x3B
>> +
>
> Yeah I know, that’s where our discussion stopped last time and would like to conclude using this series.
> https://patchwork.ozlabs.org/patch/829856/
> We discussed this sometime back and I mentioned that this controller is not just targeted for spi-nor
> but even though none tested/used with devices other than spi-nor AFAIK.
and you agree to write driver on spi side right? but you still using
flash commands.
#define QUAD_OUT_READ_CMD 0x6B
#define QUAD_PAGE_PROGRAM_CMD 0x32
#define DUAL_OUTPUT_FASTRD_CMD 0x3B
Jagan.
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