Re: [PATCH 03/15] imx: imx8mm_mx8menlo: Enable DM_SERIAL

From: Adam Ford <aford173@gmail.com>
To: Marek Vasut <marex@denx.de>
Cc: "Peng Fan (OSS)" <peng.fan@oss.nxp.com>,
	Stefano Babic <sbabic@denx.de>,
	 Fabio Estevam <festevam@gmail.com>,
	Olaf Mandel <o.mandel@menlosystems.com>,
	U-Boot Mailing List <u-boot@lists.denx.de>,
	Peng Fan <peng.fan@nxp.com>
Subject: Re: [PATCH 03/15] imx: imx8mm_mx8menlo: Enable DM_SERIAL
Date: Sat, 30 Apr 2022 13:40:41 -0500	[thread overview]
Message-ID: <CAHCN7xLh9bvS-qJFbXdst+v8PEzx0Cdap9mhT+ESGfwbOFZSNA@mail.gmail.com> (raw)
In-Reply-To: <930a599e-52c6-3d8b-ea86-70dd3bdcc9c8@denx.de>

On Sat, Apr 30, 2022 at 1:04 PM Marek Vasut <marex@denx.de> wrote:
>
> On 4/30/22 19:32, Adam Ford wrote:
> > On Sat, Apr 30, 2022 at 12:00 PM Marek Vasut <marex@denx.de> wrote:
> >>
> >> On 4/30/22 14:43, Peng Fan (OSS) wrote:
> >>> From: Peng Fan <peng.fan@nxp.com>
> >>>
> >>> Enable CONFIG_DM_SERIAL. uart2 and its pinmux was already
> >>> marked with u-boot,dm-spl.
> >>>
> >>> Signed-off-by: Peng Fan <peng.fan@nxp.com>
> >>> ---
> >>>    board/menlo/mx8menlo/mx8menlo.c   | 9 ---------
> >>>    configs/imx8mm-mx8menlo_defconfig | 1 +
> >>>    include/configs/imx8mm-mx8menlo.h | 3 ---
> >>>    3 files changed, 1 insertion(+), 12 deletions(-)
> >>>
> >>> diff --git a/board/menlo/mx8menlo/mx8menlo.c b/board/menlo/mx8menlo/mx8menlo.c
> >>> index a4d0becdcc8..95ff95ad360 100644
> >>> --- a/board/menlo/mx8menlo/mx8menlo.c
> >>> +++ b/board/menlo/mx8menlo/mx8menlo.c
> >>> @@ -12,15 +12,8 @@
> >>>    #include <asm/mach-imx/iomux-v3.h>
> >>>    #include <spl.h>
> >>>
> >>> -#define UART_PAD_CTRL        (PAD_CTL_PUE | PAD_CTL_PE | PAD_CTL_DSE4)
> >>>    #define WDOG_PAD_CTRL       (PAD_CTL_DSE6 | PAD_CTL_ODE | PAD_CTL_PUE | PAD_CTL_PE)
> >>>
> >>> -/* Verdin UART_3, Console/Debug UART */
> >>> -static iomux_v3_cfg_t const uart_pads[] = {
> >>> -     IMX8MM_PAD_SAI3_TXFS_UART2_RX | MUX_PAD_CTRL(UART_PAD_CTRL),
> >>> -     IMX8MM_PAD_SAI3_TXC_UART2_TX | MUX_PAD_CTRL(UART_PAD_CTRL),
> >>> -};
> >>> -
> >>>    static iomux_v3_cfg_t const wdog_pads[] = {
> >>>        IMX8MM_PAD_GPIO1_IO02_WDOG1_WDOG_B  | MUX_PAD_CTRL(WDOG_PAD_CTRL),
> >>>    };
> >>> @@ -48,8 +41,6 @@ void board_early_init(void)
> >>>
> >>>        set_wdog_reset(wdog);
> >>>
> >>> -     imx_iomux_v3_setup_multiple_pads(uart_pads, ARRAY_SIZE(uart_pads));
> >>> -
> >>>        init_uart_clk(1);
> >>
> >> But that means the UART is available much later in SPL ?
> >>
> >> Also, init_uart_clk(1) still hard-codes UART number , can the UART
> >> driver init those UART clock instead too ?
> >
> > I just submitted an RFC to address that [1].  The RTC is based on the
> > work Peng did.
> >
> > If people are OK with my proposal or changing the serial driver, I can
> > work on porting the 8mn and 8mp clocks to let the drivers enable the
> > clocks.
> >
> > [1] - https://patchwork.ozlabs.org/project/uboot/patch/20220430161422.558361-2-aford173@gmail.com/
>
> That still works only after spl_early_init() is called, right ?

As far as I can tell, we need spl init to run to get the device tree
stuff functional in order to enable either the clocks or the serial
port.  However, I have noticed the README states that board_init_f
should not call board_init_r directly and BSS isn't not available.  It
seems like there might be more work to do on cleaning up the various
board_init_f functions.  It seems like everyone clears BSS and calls
board_init_r directly.

I wonder if we could consolidate all these boards files into a
platform specific startup function and let people who have
board-specific stuff they need done to do it in early init or
something.

adam