[v1 10/17] arm: socfpga: Add SDRAM driver helper function for Intel N5X device

[Tan, Ley Foon]

> -----Original Message-----
> From: Lim, Elly Siew Chin <elly.siew.chin.lim at intel.com>
> Sent: Wednesday, March 31, 2021 10:39 PM
> To: u-boot at lists.denx.de
> Cc: Marek Vasut <marex at denx.de>; Tan, Ley Foon
> <ley.foon.tan at intel.com>; See, Chin Liang <chin.liang.see at intel.com>;
> Simon Goldschmidt <simon.k.r.goldschmidt at gmail.com>; Chee, Tien Fong
> <tien.fong.chee at intel.com>; Westergreen, Dalon
> <dalon.westergreen at intel.com>; Simon Glass <sjg at chromium.org>; Gan,
> Yau Wai <yau.wai.gan at intel.com>; Lim, Elly Siew Chin
> <elly.siew.chin.lim at intel.com>
> Subject: [v1 10/17] arm: socfpga: Add SDRAM driver helper function for Intel
> N5X device
> 
> Add is_ddr_init_skipped function to check if need to skip DDR initialization
> for N5X. This patch is preparation for N5X DDR driver support.
> 
> Signed-off-by: Siew Chin Lim <elly.siew.chin.lim at intel.com>
> Signed-off-by: Tien Fong Chee <tien.fong.chee at intel.com>
> ---
>  arch/arm/mach-socfpga/include/mach/misc.h |  4 ++
>  arch/arm/mach-socfpga/misc_soc64.c        | 67
> ++++++++++++++++++++++++++++++-
>  2 files changed, 70 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm/mach-socfpga/include/mach/misc.h b/arch/arm/mach-
> socfpga/include/mach/misc.h
> index 649d2f6ce2..c41b7c14cd 100644
> --- a/arch/arm/mach-socfpga/include/mach/misc.h
> +++ b/arch/arm/mach-socfpga/include/mach/misc.h
> @@ -44,6 +44,10 @@ void socfpga_sdram_remap_zero(void);  int
> is_fpga_config_ready(void);  #endif
> 
> +#if IS_ENABLED(CONFIG_TARGET_SOCFPGA_N5X)
> +bool is_ddr_init_skipped(void);
> +#endif
> +
>  void do_bridge_reset(int enable, unsigned int mask);  void
> socfpga_pl310_clear(void);  void socfpga_get_managers_addr(void); diff --git
> a/arch/arm/mach-socfpga/misc_soc64.c b/arch/arm/mach-
> socfpga/misc_soc64.c
> index 7b973a79e8..d3945e55aa 100644
> --- a/arch/arm/mach-socfpga/misc_soc64.c
> +++ b/arch/arm/mach-socfpga/misc_soc64.c
> @@ -1,6 +1,6 @@
>  // SPDX-License-Identifier: GPL-2.0
>  /*
> - * Copyright (C) 2016-2018 Intel Corporation <www.intel.com>
> + * Copyright (C) 2016-2021 Intel Corporation <www.intel.com>
>   *
>   */
> 
> @@ -19,6 +19,13 @@
> 
>  DECLARE_GLOBAL_DATA_PTR;
> 
> +/* Reset type */
> +enum reset_type {
> +	POR_RESET,
> +	WARM_RESET,
> +	COLD_RESET
> +};
> +
>  /*
>   * FPGA programming support for SoC FPGA Stratix 10
>   */
> @@ -88,3 +95,61 @@ void do_bridge_reset(int enable, unsigned int mask)
> 
>  	socfpga_bridges_reset(enable);
>  }
> +
> +#if IS_ENABLED(CONFIG_TARGET_SOCFPGA_N5X)
> +static bool is_ddr_retention_enabled(u32 boot_scratch_cold0_reg) {
> +	return boot_scratch_cold0_reg &
> +	       ALT_SYSMGR_SCRATCH_REG_0_DDR_RETENTION_MASK;
> +}
> +
> +static bool is_ddr_bitstream_sha_matching(u32 boot_scratch_cold0_reg) {
> +	return boot_scratch_cold0_reg &
> ALT_SYSMGR_SCRATCH_REG_0_DDR_SHA_MASK;
> +}
> +
> +static enum reset_type get_reset_type(u32 boot_scratch_cold0_reg) {
> +	return (boot_scratch_cold0_reg &
> +		ALT_SYSMGR_SCRATCH_REG_0_DDR_RESET_TYPE_MASK) >>
> +		ALT_SYSMGR_SCRATCH_REG_0_DDR_RESET_TYPE_SHIFT;
> +}
> +
> +bool is_ddr_init_skipped(void)

1. This function can move to DDR driver.
2. Change this function return true if need the DDR init, so that doesn't need to invert checking when call to this function, more readable.

> +{
> +	u32 reg = readl(socfpga_get_sysmgr_addr() +
> +			SYSMGR_SOC64_BOOT_SCRATCH_COLD0);
> +
> +	if (get_reset_type(reg) == POR_RESET) {
Store reset type in a variable, don't call get_reset_type() multiple times.

> +		debug("%s: POR reset is triggered\n", __func__);
> +		debug("%s: DDR init is required\n", __func__);
> +		return false;
> +	}
> +
> +	if (get_reset_type(reg) == WARM_RESET) {
> +		debug("%s: Warm reset is triggered\n", __func__);
> +		debug("%s: DDR init is skipped\n", __func__);
> +		return true;
> +	}
> +
> +	if (get_reset_type(reg) == COLD_RESET) {
> +		debug("%s: Cold reset is triggered\n", __func__);
> +
> +		if (is_ddr_retention_enabled(reg)) {
> +			debug("%s: DDR retention bit is set\n", __func__);
> +
> +			if (is_ddr_bitstream_sha_matching(reg)) {
Combine this IF with parent IF with &&.

> +				debug("%s: Matching in DDR bistream\n",
> +				      __func__);
> +				debug("%s: DDR init is skipped\n", __func__);
> +				return true;
> +			}
> +
> +			debug("%s: Mismatch in DDR bistream\n", __func__);
> +		}
> +	}
> +
> +	debug("%s: DDR init is required\n", __func__);
> +	return false;
> +}
> +#endif
> --
> 2.13.0