[PATCH] ARM: i.MX7: don't hardcode UART1 in imx7_early_setup_uart_clock

[Sascha Hauer]

On Mon, Oct 10, 2022 at 09:48:34AM +0200, Ahmad Fatoum wrote:
> imx7_early_setup_uart_clock() has a very generic sounding name, but so
> far only set up clocks for UART1. This can lead board code authors
> astray that intend to user a different UART for DEBUG_LL.
> 
> This issue affects board code for kamstrup-mx7-concentrator, meerkat96
> and zii-imx7d-dev, which use UART4, UART6 and UART2 respectively.
> 
> As I don't have this boards available to test and clock changes may have
> adverse effect elsewhere, we have all existing users setup UART1 as
> before, but note with a comment that this may not be the original
> author's intention.
> 
> Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
> ---
> I have CC'd authors of the three likely misconfigured boards,
> in case they want to fix them and test.
> ---
>  arch/arm/boards/ac-sxb/lowlevel.c             |  2 +-
>  .../boards/freescale-mx7-sabresd/lowlevel.c   |  2 +-
>  .../kamstrup-mx7-concentrator/lowlevel.c      |  3 ++-
>  arch/arm/boards/meerkat96/lowlevel.c          |  3 ++-
>  arch/arm/boards/zii-imx7d-dev/lowlevel.c      |  3 ++-
>  .../arm/mach-imx/include/mach/imx7-ccm-regs.h | 21 +++++++++----------
>  6 files changed, 18 insertions(+), 16 deletions(-)
> 
> diff --git a/arch/arm/boards/ac-sxb/lowlevel.c b/arch/arm/boards/ac-sxb/lowlevel.c
> index a910555f9bd7..a26454968304 100644
> --- a/arch/arm/boards/ac-sxb/lowlevel.c
> +++ b/arch/arm/boards/ac-sxb/lowlevel.c
> @@ -93,7 +93,7 @@ extern char __dtb_z_ac_sxb_start[];
>  
>  static inline void setup_uart(void)
>  {
> -	imx7_early_setup_uart_clock();
> +	imx7_early_setup_uart_clock(1);
>  
>  	imx7_setup_pad(MX7D_PAD_UART1_TX_DATA__UART1_DCE_TX);
>  
> diff --git a/arch/arm/boards/freescale-mx7-sabresd/lowlevel.c b/arch/arm/boards/freescale-mx7-sabresd/lowlevel.c
> index a8733d62091f..6d393bf2b10e 100644
> --- a/arch/arm/boards/freescale-mx7-sabresd/lowlevel.c
> +++ b/arch/arm/boards/freescale-mx7-sabresd/lowlevel.c
> @@ -17,7 +17,7 @@ extern char __dtb_imx7d_sdb_start[];
>  
>  static inline void setup_uart(void)
>  {
> -	imx7_early_setup_uart_clock();
> +	imx7_early_setup_uart_clock(1);
>  
>  	imx7_setup_pad(MX7D_PAD_UART1_TX_DATA__UART1_DCE_TX);
>  
> diff --git a/arch/arm/boards/kamstrup-mx7-concentrator/lowlevel.c b/arch/arm/boards/kamstrup-mx7-concentrator/lowlevel.c
> index 4a9eae80d153..511f01757c46 100644
> --- a/arch/arm/boards/kamstrup-mx7-concentrator/lowlevel.c
> +++ b/arch/arm/boards/kamstrup-mx7-concentrator/lowlevel.c
> @@ -17,7 +17,8 @@ extern char __dtb_z_imx7d_flex_concentrator_mfg_start[];
>  
>  static inline void setup_uart(void)
>  {
> -	imx7_early_setup_uart_clock();
> +	/* FIXME: Below UART4 is muxed, not UART1 */
> +	imx7_early_setup_uart_clock(1);
>  
>  	imx7_setup_pad(MX7D_PAD_SAI2_TX_BCLK__UART4_DCE_TX);
>  
> diff --git a/arch/arm/boards/meerkat96/lowlevel.c b/arch/arm/boards/meerkat96/lowlevel.c
> index 1c9baeacfb2a..e65726ef1c27 100644
> --- a/arch/arm/boards/meerkat96/lowlevel.c
> +++ b/arch/arm/boards/meerkat96/lowlevel.c
> @@ -14,7 +14,8 @@ extern char __dtb_z_imx7d_meerkat96_start[];
>  
>  static void setup_uart(void)
>  {
> -	imx7_early_setup_uart_clock();
> +	/* FIXME: Below UART6 is muxed, not UART1 */
> +	imx7_early_setup_uart_clock(1);
>  	imx7_setup_pad(MX7D_PAD_SD1_WP__UART6_DCE_TX);
>  	imx7_uart_setup_ll();
>  	putc_ll('>');
> diff --git a/arch/arm/boards/zii-imx7d-dev/lowlevel.c b/arch/arm/boards/zii-imx7d-dev/lowlevel.c
> index 7579a2a8a050..0e316b602436 100644
> --- a/arch/arm/boards/zii-imx7d-dev/lowlevel.c
> +++ b/arch/arm/boards/zii-imx7d-dev/lowlevel.c
> @@ -23,7 +23,8 @@ extern char __dtb_z_imx7d_zii_rmu2_start[];
>  
>  static inline void setup_uart(void)
>  {
> -	imx7_early_setup_uart_clock();
> +	/* FIXME: Below UART2 is muxed, not UART1 */
> +	imx7_early_setup_uart_clock(1);
>  
>  	imx7_setup_pad(MX7D_PAD_UART2_TX_DATA__UART2_DCE_TX);
>  
> diff --git a/arch/arm/mach-imx/include/mach/imx7-ccm-regs.h b/arch/arm/mach-imx/include/mach/imx7-ccm-regs.h
> index aecf9a26d017..0ef0742bb65d 100644
> --- a/arch/arm/mach-imx/include/mach/imx7-ccm-regs.h
> +++ b/arch/arm/mach-imx/include/mach/imx7-ccm-regs.h
> @@ -39,16 +39,15 @@
>  #define IMX7_CCM_CCGR_SETTINGn_NEEDED_RUN_WAIT(n)	IMX7_CCM_CCGR_SETTINGn(n, 0b10)
>  #define IMX7_CCM_CCGR_SETTINGn_NEEDED(n)		IMX7_CCM_CCGR_SETTINGn(n, 0b11)
>  
> -static inline void imx7_early_setup_uart_clock(void)
> -{
> -	void __iomem *ccm   = IOMEM(MX7_CCM_BASE_ADDR);
> -
> -	writel(IMX7_CCM_CCGR_SETTINGn_NEEDED(0),
> -	       ccm + IMX7_CCM_CCGRn_CLR(IMX7_CCM_CCGR_UART1));
> -	writel(IMX7_CCM_TARGET_ROOTn_ENABLE | IMX7_UART1_CLK_ROOT__OSC_24M,
> -	       ccm + IMX7_CCM_TARGET_ROOTn(IMX7_UART1_CLK_ROOT));
> -	writel(IMX7_CCM_CCGR_SETTINGn_NEEDED(0),
> -	       ccm + IMX7_CCM_CCGRn_SET(IMX7_CCM_CCGR_UART1));
> -}
> +/* UART counting starts for 1, like in the datasheet/dt-bindings */
> +#define imx7_early_setup_uart_clock(uart) do { \
> +	void __iomem *ccm   = IOMEM(MX7_CCM_BASE_ADDR); \
> +	writel(IMX7_CCM_CCGR_SETTINGn_NEEDED(0), \
> +	       ccm + IMX7_CCM_CCGRn_CLR(IMX7_CCM_CCGR_UART ## uart)); \

You could do:

#define IMX7_CCM_CCGR_UART(n)	(148 + (n))		/* 0 <= n <= 5 */
#define IMX7_UART_CLK_ROOT(n)	(0xaf80 + (n) * 0x80)	/* 0 <= n <= 5 */

to avoid converting this into a macro.

Sascha

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