[PATCH v3 6/7] drivers: ddr: altera: Improve DRAM init with Dcache

[Chee, Tien Fong]

Hi,

> -----Original Message-----
> From: Ravulapalli, Naresh Kumar <naresh.kumar.ravulapalli at altera.com>
> Sent: Tuesday, June 3, 2025 7:55 PM
> To: u-boot at lists.denx.de
> Cc: Marek Vasut <marex at denx.de>; Simon Goldschmidt
> <simon.k.r.goldschmidt at gmail.com>; Chee, Tien Fong
> <tien.fong.chee at altera.com>; Tom Rini <trini at konsulko.com>; Ravulapalli,
> Naresh Kumar <naresh.kumar.ravulapalli at altera.com>
> Subject: [PATCH v3 6/7] drivers: ddr: altera: Improve DRAM init with Dcache
> 
> Initialize DRAM memory fully to bring it into a known state. The process is
> improved by enabling the Dcache. Also, if hardware watchdog is configured,
> it is reconfigured to avoid timeout.
> 
> Signed-off-by: Naresh Kumar Ravulapalli
> <nareshkumar.ravulapalli at altera.com>
> Signed-off-by: Tien Fong Chee <tien.fong.chee at altera.com>
> ---
>  drivers/ddr/altera/sdram_arria10.c |  3 +-
>  drivers/ddr/altera/sdram_soc32.c   | 52 ++++++++++++++++++++++++------
>  drivers/ddr/altera/sdram_soc32.h   |  2 +-
>  3 files changed, 45 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/ddr/altera/sdram_arria10.c
> b/drivers/ddr/altera/sdram_arria10.c
> index a1288d5fb50..6cb5002208b 100644
> --- a/drivers/ddr/altera/sdram_arria10.c
> +++ b/drivers/ddr/altera/sdram_arria10.c
> @@ -4,7 +4,6 @@
>   * Copyright (C) 2025 Altera Corporation <www.altera.com>
>   */
> 
> -#include <cpu_func.h>
>  #include <errno.h>
>  #include <fdtdec.h>
>  #include <init.h>
> @@ -719,7 +718,7 @@ int ddr_calibration_sequence(void)
>  		puts("FW: Error Configuring Firewall\n");
> 
>  	if (sdram_is_ecc_enabled())
> -		sdram_init_ecc_bits(gd->ram_size);
> +		sdram_init_ecc_bits();
> 
>  	sdram_size_check();
> 
> diff --git a/drivers/ddr/altera/sdram_soc32.c
> b/drivers/ddr/altera/sdram_soc32.c
> index 0b928a2352f..5cdf48d2d01 100644
> --- a/drivers/ddr/altera/sdram_soc32.c
> +++ b/drivers/ddr/altera/sdram_soc32.c
> @@ -7,25 +7,59 @@
>  #include <asm/system.h>
>  #include <linux/sizes.h>
>  #include "sdram_soc32.h"
> +#include <watchdog.h>

Moving the watchdog.h as first header
https://docs.u-boot.org/en/latest/develop/codingstyle.html
Please refer Include Header section

> 
>  DECLARE_GLOBAL_DATA_PTR;
> 
>  #define PGTABLE_OFF	0x4000
> 
>  /* Initialize SDRAM ECC bits to avoid false DBE */ -void
> sdram_init_ecc_bits(u32 size)
> +void sdram_init_ecc_bits(void)
>  {
> -	icache_enable();
> +	u32 start;
> +	phys_addr_t start_addr, saved_start;
> +	phys_size_t size, size_init, saved_size;
> +	enum dcache_option option = DCACHE_WRITEBACK;
> 
> -	memset(0, 0, 0x8000);
> -	gd->arch.tlb_addr = 0x4000;
> -	gd->arch.tlb_size = PGTABLE_SIZE;
> +	if (IS_ENABLED(CONFIG_SYS_ARM_CACHE_WRITETHROUGH))
> +		option = DCACHE_WRITETHROUGH;
> +	else if (IS_ENABLED(CONFIG_SYS_ARM_CACHE_WRITEALLOC))
> +		option = DCACHE_WRITEALLOC;
> +
> +	start = get_timer(0);
> +
> +	start_addr = gd->bd->bi_dram[0].start;
> +	size = gd->bd->bi_dram[0].size;
> 
> +	printf("DDRCAL: Initialize ECC RAM (%ld MiB).\n", size >> 20);
> +
> +	memset((void *)start_addr, 0, PGTABLE_SIZE + PGTABLE_OFF);
> +	gd->arch.tlb_addr = start_addr + PGTABLE_OFF;
> +	gd->arch.tlb_size = PGTABLE_SIZE;
> +	start_addr += PGTABLE_SIZE + PGTABLE_OFF;
> +	size -= (PGTABLE_OFF + PGTABLE_SIZE);
>  	dcache_enable();
> 
> -	printf("DDRCAL: Scrubbing ECC RAM (%i MiB).\n", size >> 20);
> -	memset((void *)0x8000, 0, size - 0x8000);
> -	flush_dcache_all();
> -	printf("DDRCAL: Scrubbing ECC RAM done.\n");
> +	saved_start = start_addr;
> +	saved_size = size;
> +	/* Set SDRAM region to writethrough to avoid false double-bit error.
> */
> +	mmu_set_region_dcache_behaviour(saved_start, saved_size,
> +					DCACHE_WRITETHROUGH);
> +
> +	while (size > 0) {
> +		size_init = min((phys_addr_t)SZ_1G, (phys_addr_t)size);
> +		memset((void *)start_addr, 0, size_init);
> +		size -= size_init;
> +		start_addr += size_init;
> +		schedule();
> +	}
> +
>  	dcache_disable();
> +
> +	/* Restore back to original dcache behaviour. */
> +	mmu_set_region_dcache_behaviour(saved_start, saved_size,
> +					option);
> +
> +	printf("DDRCAL: SDRAM-ECC successfully initialized within %d ms\n",
> +	       (u32)get_timer(start));
>  }
> diff --git a/drivers/ddr/altera/sdram_soc32.h
> b/drivers/ddr/altera/sdram_soc32.h
> index 4c6137e728d..85a951a5a74 100644
> --- a/drivers/ddr/altera/sdram_soc32.h
> +++ b/drivers/ddr/altera/sdram_soc32.h
> @@ -6,6 +6,6 @@
>  #ifndef	_SDRAM_SOC32_H_
>  #define	_SDRAM_SOC32_H_
> 
> -void sdram_init_ecc_bits(u32 size);
> +void sdram_init_ecc_bits(void);
> 
>  #endif /* _SDRAM_SOC32_H_ */
> --
> 2.35.3

BR,
Tien Fong