Re: [PATCH] mmc: rtsx: change phase searching method

[micky <micky_ching@realsil.com.cn>]

Hi Chris:

Have you accepted this patch,  I'm waiting a long time for your reply.

Best Reagards.
micky

On 09/02/2013 05:16 PM, micky_ching@realsil.com.cn wrote:
> From: Micky Ching <micky_ching@realsil.com.cn>
>
> The new phase searching method is more concise, and makes the code
> easier to understand.
>
> Signed-off-by: Micky Ching <micky_ching@realsil.com.cn>
> ---
>   drivers/mmc/host/rtsx_pci_sdmmc.c |  107 +++++++++++--------------------------
>   1 file changed, 30 insertions(+), 77 deletions(-)
>
> diff --git a/drivers/mmc/host/rtsx_pci_sdmmc.c b/drivers/mmc/host/rtsx_pci_sdmmc.c
> index f981f7d..299a27c 100644
> --- a/drivers/mmc/host/rtsx_pci_sdmmc.c
> +++ b/drivers/mmc/host/rtsx_pci_sdmmc.c
> @@ -32,15 +32,6 @@
>   #include <linux/mfd/rtsx_pci.h>
>   #include <asm/unaligned.h>
>   
> -/* SD Tuning Data Structure
> - * Record continuous timing phase path
> - */
> -struct timing_phase_path {
> -	int start;
> -	int end;
> -	int mid;
> -	int len;
> -};
>   
>   struct realtek_pci_sdmmc {
>   	struct platform_device	*pdev;
> @@ -497,85 +488,47 @@ static int sd_change_phase(struct realtek_pci_sdmmc *host, u8 sample_point)
>   	return 0;
>   }
>   
> -static u8 sd_search_final_phase(struct realtek_pci_sdmmc *host, u32 phase_map)
> +static inline u32 get_phase_point(u32 phase_map, unsigned int idx)
>   {
> -	struct timing_phase_path path[MAX_PHASE + 1];
> -	int i, j, cont_path_cnt;
> -	int new_block, max_len, final_path_idx;
> -	u8 final_phase = 0xFF;
> +	idx &= MAX_PHASE;
> +	return phase_map & (1 << idx);
> +}
> +
> +static int get_phase_len(u32 phase_map, unsigned int idx)
> +{
> +	int i;
>   
> -	/* Parse phase_map, take it as a bit-ring */
> -	cont_path_cnt = 0;
> -	new_block = 1;
> -	j = 0;
>   	for (i = 0; i < MAX_PHASE + 1; i++) {
> -		if (phase_map & (1 << i)) {
> -			if (new_block) {
> -				new_block = 0;
> -				j = cont_path_cnt++;
> -				path[j].start = i;
> -				path[j].end = i;
> -			} else {
> -				path[j].end = i;
> -			}
> -		} else {
> -			new_block = 1;
> -			if (cont_path_cnt) {
> -				/* Calculate path length and middle point */
> -				int idx = cont_path_cnt - 1;
> -				path[idx].len =
> -					path[idx].end - path[idx].start + 1;
> -				path[idx].mid =
> -					path[idx].start + path[idx].len / 2;
> -			}
> -		}
> +		if (get_phase_point(phase_map, idx + i) == 0)
> +			return i;
>   	}
> +	return MAX_PHASE + 1;
> +}
>   
> -	if (cont_path_cnt == 0) {
> -		dev_dbg(sdmmc_dev(host), "No continuous phase path\n");
> -		goto finish;
> -	} else {
> -		/* Calculate last continuous path length and middle point */
> -		int idx = cont_path_cnt - 1;
> -		path[idx].len = path[idx].end - path[idx].start + 1;
> -		path[idx].mid = path[idx].start + path[idx].len / 2;
> -	}
> +static u8 sd_search_final_phase(struct realtek_pci_sdmmc *host, u32 phase_map)
> +{
> +	int start = 0, len = 0;
> +	int start_final = 0, len_final = 0;
> +	u8 final_phase = 0xFF;
>   
> -	/* Connect the first and last continuous paths if they are adjacent */
> -	if (!path[0].start && (path[cont_path_cnt - 1].end == MAX_PHASE)) {
> -		/* Using negative index */
> -		path[0].start = path[cont_path_cnt - 1].start - MAX_PHASE - 1;
> -		path[0].len += path[cont_path_cnt - 1].len;
> -		path[0].mid = path[0].start + path[0].len / 2;
> -		/* Convert negative middle point index to positive one */
> -		if (path[0].mid < 0)
> -			path[0].mid += MAX_PHASE + 1;
> -		cont_path_cnt--;
> +	if (phase_map == 0) {
> +		dev_dbg(sdmmc_dev(host), "Phase: [map:%x]\n", phase_map);
> +		return final_phase;
>   	}
>   
> -	/* Choose the longest continuous phase path */
> -	max_len = 0;
> -	final_phase = 0;
> -	final_path_idx = 0;
> -	for (i = 0; i < cont_path_cnt; i++) {
> -		if (path[i].len > max_len) {
> -			max_len = path[i].len;
> -			final_phase = (u8)path[i].mid;
> -			final_path_idx = i;
> +	while (start < MAX_PHASE + 1) {
> +		len = get_phase_len(phase_map, start);
> +		if (len_final < len) {
> +			start_final = start;
> +			len_final = len;
>   		}
> -
> -		dev_dbg(sdmmc_dev(host), "path[%d].start = %d\n",
> -				i, path[i].start);
> -		dev_dbg(sdmmc_dev(host), "path[%d].end = %d\n",
> -				i, path[i].end);
> -		dev_dbg(sdmmc_dev(host), "path[%d].len = %d\n",
> -				i, path[i].len);
> -		dev_dbg(sdmmc_dev(host), "path[%d].mid = %d\n",
> -				i, path[i].mid);
> +		start += len ? len : 1;
>   	}
>   
> -finish:
> -	dev_dbg(sdmmc_dev(host), "Final chosen phase: %d\n", final_phase);
> +	final_phase = (start_final + len_final / 2) & MAX_PHASE;
> +	dev_dbg(sdmmc_dev(host), "Phase: [map:%x] [maxlen:%d] [final:%d]\n",
> +		phase_map, len_final, final_phase);
> +
>   	return final_phase;
>   }
>