[PATCH] riscv: spacemit: k1: probe dram size during boot phase.

[Heinrich Schuchardt]

Am 8. Januar 2025 12:11:05 MEZ schrieb Yixun Lan <dlan at gentoo.org>:
>Hi Huan:
>
>On 16:49 Wed 08 Jan     , Huan Zhou wrote:
>> 
>> 
>..
>> ---
>remove above "---"? otherwise following commit message will be
>dropped during patch application..
>
>> This patch introduce improvement for get dram size on bananapi BPI-F3,
>> retrieving the dram size dynamically.
>> Have tested on bananapi BPIF3 4G and jupiter 8G.
>> 
>> Signed-off-by: Huan Zhou <me at per1cycle.org>
>> ---
>>  arch/riscv/cpu/k1/dram.c | 40 ++++++++++++++++++++++++++++++++++++++--
>>  1 file changed, 38 insertions(+), 2 deletions(-)
>> 
>> diff --git a/arch/riscv/cpu/k1/dram.c b/arch/riscv/cpu/k1/dram.c
>> index c477c15cbfb19f0e3a0ee72985b602f5bda352d7..095217f2a4c053f7477d62c0776bcb51e623db47 100644
>> --- a/arch/riscv/cpu/k1/dram.c
>> +++ b/arch/riscv/cpu/k1/dram.c
>> @@ -4,17 +4,53 @@
>>   */
>>  
>>  #include <asm/global_data.h>
>> +#include <asm/io.h>
>>  #include <config.h>
>> +#include <bitfield.h>
>>  #include <fdt_support.h>
>>  #include <linux/sizes.h>
>>  
>> +#define DDR_BASE 0xC0000000
>>  DECLARE_GLOBAL_DATA_PTR;
>>  
>> +static inline u32 map_format_size(u32 val)
>> +{
>> +	u32 tmp;
>> +
>> +	if (val & 0x1 == 0)
>please add brackets explicitly, something like
>	if ((val & 0x1) == 0)

We tend to avoid == 0 in U-Boot

if (val & BIT(0))

>
>> +		return 0;
>> +
>> +	tmp = bitfield_extract(val, 16, 5);
>> +	switch (tmp) {
>> +	case 0xd:
>> +		return 512;
>> +	case 0xe:
>> +		return 1024;
>> +	case 0xf:
>> +		return 2048;
>> +	case 0x10:
>> +		return 4096;
>> +	case 0x11:
>> +		return 8192;
>> +	default:
>> +		pr_info("Invalid DRAM density %x\n", val);
>> +		return 0;
>> +	}
>> +}
>> +
>> +u32 ddr_get_density(void)
>> +{
>> +	u32 cs0_size = map_format_size(readl((void *)DDR_BASE + 0x200));
>> +	u32 cs1_size = map_format_size(readl((void *)DDR_BASE + 0x208));
>> +	u32 ddr_size = cs0_size + cs1_size;
>> +
>> +	return ddr_size;
>> +}
>> +
>>  int dram_init(void)
>>  {
>>  	gd->ram_base = CFG_SYS_SDRAM_BASE;
>> -	/* TODO get ram size from ddr controller */
>> -	gd->ram_size = SZ_4G;
>> +	gd->ram_size = (u64)ddr_get_density() * SZ_1M;

This is C and not C++. We don't need a cast to assign here.

Best regards

Heinrich

>while using cast, why not define ddr_get_density() return as same type?
>also it's more reasonable to use phys_size_t as I checked gd_t
>
>>  	return 0;
>>  }
>>  
>> 
>> ---
>> base-commit: 19fc0b7f7d907119a13e9c207991899f0817f8fc
>> change-id: 20250108-get-dram-size-65cf59a15201
>> 
>> Best regards,
>> -- 
>> Huan Zhou <me at per1cycle.org>
>> 
>