Re: [PATCH v2 2/5] apq8016: Add support for UART1 clocks and pinmux

[Caleb Connolly <caleb.connolly@linaro.org>]

Hi Sumit,

On 11/03/2024 11:10, Sumit Garg wrote:
> SE HMIBSC board uses UART1 as the main debug console, so add
> corresponding clocks and pinmux support. Along with that update
> instructions to enable clocks for debug UART support.
> 
> Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
> ---
>  drivers/clk/qcom/clock-apq8016.c       | 50 +++++++++++++++++++++-----
>  drivers/pinctrl/qcom/pinctrl-apq8016.c |  1 +
>  drivers/serial/serial_msm.c            |  6 ++--
>  3 files changed, 47 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/clk/qcom/clock-apq8016.c b/drivers/clk/qcom/clock-apq8016.c
> index e6647f7c41d..a620a10a520 100644
> --- a/drivers/clk/qcom/clock-apq8016.c
> +++ b/drivers/clk/qcom/clock-apq8016.c
> @@ -43,6 +43,14 @@
>  #define BLSP1_UART2_APPS_N		(0x3040)
>  #define BLSP1_UART2_APPS_D		(0x3044)
>  
> +#define BLSP1_UART1_BCR			(0x2038)
> +#define BLSP1_UART1_APPS_CBCR		(0x203C)
> +#define BLSP1_UART1_APPS_CMD_RCGR	(0x2044)
> +#define BLSP1_UART1_APPS_CFG_RCGR	(0x2048)
> +#define BLSP1_UART1_APPS_M		(0x204C)
> +#define BLSP1_UART1_APPS_N		(0x2050)
> +#define BLSP1_UART1_APPS_D		(0x2054)
> +
>  /* GPLL0 clock control registers */
>  #define GPLL0_STATUS_ACTIVE BIT(17)
>  
> @@ -77,7 +85,7 @@ static struct vote_clk gcc_blsp1_ahb_clk = {
>  };
>  
>  /* SDHCI */
> -static int clk_init_sdc(struct msm_clk_priv *priv, int slot, uint rate)
> +static int apq8016_clk_init_sdc(struct msm_clk_priv *priv, int slot, uint rate)
This seems like an unrelated change, I don't think we need to namespace
this function as it's static.
>  {
>  	int div = 15; /* 100MHz default */
>  
> @@ -94,6 +102,33 @@ static int clk_init_sdc(struct msm_clk_priv *priv, int slot, uint rate)
>  	return rate;
>  }
>  
> +static const struct bcr_regs uart1_regs = {
> +	.cfg_rcgr = BLSP1_UART1_APPS_CFG_RCGR,
> +	.cmd_rcgr = BLSP1_UART1_APPS_CMD_RCGR,
> +	.M = BLSP1_UART1_APPS_M,
> +	.N = BLSP1_UART1_APPS_N,
> +	.D = BLSP1_UART1_APPS_D,
> +};
> +
> +/* UART: 115200 */
> +static int apq8016_clk_init_uart1(phys_addr_t base)

I know we're still dealing with some tech debt here, but I'm not a big
fan of this approach. I notice that the RCG and CBCR registers are all
offset by exactly 0xff0 between UART1 and UART2, what about adding a
second "index" parameter to apq8016_clk_init_uart() and then offsetting
the addresses by (0xff0 * index)?

This will get cleaner once we drop the bcr_regs struct.
> +{
> +	/* Enable AHB clock */
> +	clk_enable_vote_clk(base, &gcc_blsp1_ahb_clk);
> +
> +	/* 7372800 uart block clock @ GPLL0 */
> +	clk_rcg_set_rate_mnd(base, &uart1_regs, 1, 144, 15625,
> +			     CFG_CLK_SRC_GPLL0, 16);
> +
> +	/* Vote for gpll0 clock */
> +	clk_enable_gpll0(base, &gpll0_vote_clk);
> +
> +	/* Enable core clk */
> +	clk_enable_cbc(base + BLSP1_UART1_APPS_CBCR);
> +
> +	return 0;
> +}
> +
>  static const struct bcr_regs uart2_regs = {
>  	.cfg_rcgr = BLSP1_UART2_APPS_CFG_RCGR,
>  	.cmd_rcgr = BLSP1_UART2_APPS_CMD_RCGR,
> @@ -103,7 +138,7 @@ static const struct bcr_regs uart2_regs = {
>  };
>  
>  /* UART: 115200 */
> -int apq8016_clk_init_uart(phys_addr_t base)
> +int apq8016_clk_init_uart2(phys_addr_t base)
>  {
>  	/* Enable AHB clock */
>  	clk_enable_vote_clk(base, &gcc_blsp1_ahb_clk);
> @@ -127,14 +162,13 @@ static ulong apq8016_clk_set_rate(struct clk *clk, ulong rate)
>  
>  	switch (clk->id) {
>  	case GCC_SDCC1_APPS_CLK: /* SDC1 */
> -		return clk_init_sdc(priv, 0, rate);
> -		break;
> +		return apq8016_clk_init_sdc(priv, 0, rate);
>  	case GCC_SDCC2_APPS_CLK: /* SDC2 */
> -		return clk_init_sdc(priv, 1, rate);
> -		break;
> +		return apq8016_clk_init_sdc(priv, 1, rate);
>  	case GCC_BLSP1_UART2_APPS_CLK: /* UART2 */
> -		return apq8016_clk_init_uart(priv->base);
> -		break;
> +		return apq8016_clk_init_uart2(priv->base);
> +	case GCC_BLSP1_UART1_APPS_CLK: /* UART1 */
> +		return apq8016_clk_init_uart1(priv->base);
>  	default:
>  		return 0;
>  	}
> diff --git a/drivers/pinctrl/qcom/pinctrl-apq8016.c b/drivers/pinctrl/qcom/pinctrl-apq8016.c
> index db0e2124684..cb0e2227079 100644
> --- a/drivers/pinctrl/qcom/pinctrl-apq8016.c
> +++ b/drivers/pinctrl/qcom/pinctrl-apq8016.c
> @@ -29,6 +29,7 @@ static const char * const msm_pinctrl_pins[] = {
>  };
>  
>  static const struct pinctrl_function msm_pinctrl_functions[] = {
> +	{"blsp_uart1", 2},
>  	{"blsp_uart2", 2},
>  };
>  
> diff --git a/drivers/serial/serial_msm.c b/drivers/serial/serial_msm.c
> index ac4280c6c4c..eaf024a55b0 100644
> --- a/drivers/serial/serial_msm.c
> +++ b/drivers/serial/serial_msm.c
> @@ -248,12 +248,14 @@ static struct msm_serial_data init_serial_data = {
>  #include <debug_uart.h>
>  
>  /* Uncomment to turn on UART clocks when debugging U-Boot as aboot on MSM8916 */
Please update the comment to offer some hints about which UART should be
enabled.
> -//int apq8016_clk_init_uart(phys_addr_t gcc_base);
> +//int apq8016_clk_init_uart1(phys_addr_t gcc_base);
> +//int apq8016_clk_init_uart2(phys_addr_t gcc_base);
>  
>  static inline void _debug_uart_init(void)
>  {
>  	/* Uncomment to turn on UART clocks when debugging U-Boot as aboot on MSM8916 */
> -	//apq8016_clk_init_uart(0x1800000);
> +	//apq8016_clk_init_uart1(0x1800000);
> +	//apq8016_clk_init_uart2(0x1800000);
>  	uart_dm_init(&init_serial_data);
>  }
>  

-- 
// Caleb (they/them)