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Subject[PATCH RESEND 2/3] mmc: rtsx: modify phase searching method for tuning
Date
From: Micky Ching <micky_ching@realsil.com.cn>

The new phase searching method is more concise and easier to
understand.

Signed-off-by: Micky Ching <micky_ching@realsil.com.cn>
---
drivers/mmc/host/rtsx_pci_sdmmc.c | 112 +++++++++++--------------------------
include/linux/mfd/rtsx_pci.h | 2 +-
2 files changed, 33 insertions(+), 81 deletions(-)

diff --git a/drivers/mmc/host/rtsx_pci_sdmmc.c b/drivers/mmc/host/rtsx_pci_sdmmc.c
index c9a7328..7da270b 100644
--- a/drivers/mmc/host/rtsx_pci_sdmmc.c
+++ b/drivers/mmc/host/rtsx_pci_sdmmc.c
@@ -31,16 +31,6 @@
#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;
struct rtsx_pcr *pcr;
@@ -511,85 +501,47 @@ static int sd_change_phase(struct realtek_pci_sdmmc *host,
return 0;
}

-static u8 sd_search_final_phase(struct realtek_pci_sdmmc *host, u32 phase_map)
+static inline u32 test_phase_bit(u32 phase_map, unsigned int bit)
{
- 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;
+ bit %= RTSX_PHASE_MAX;
+ return phase_map & (1 << bit);
+}

- /* 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;
- }
- }
- }
+static int sd_get_phase_len(u32 phase_map, unsigned int start_bit)
+{
+ int i;

- 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;
+ for (i = 0; i < RTSX_PHASE_MAX; i++) {
+ if (test_phase_bit(phase_map, start_bit + i) == 0)
+ return i;
}
+ return RTSX_PHASE_MAX;
+}
+
+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_err(sdmmc_dev(host), "phase error: [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 < RTSX_PHASE_MAX) {
+ len = sd_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) % RTSX_PHASE_MAX;
+ dev_dbg(sdmmc_dev(host), "phase: [map:%x] [maxlen:%d] [final:%d]\n",
+ phase_map, len_final, final_phase);
+
return final_phase;
}

@@ -635,7 +587,7 @@ static int sd_tuning_phase(struct realtek_pci_sdmmc *host,
int err, i;
u32 raw_phase_map = 0;

- for (i = MAX_PHASE; i >= 0; i--) {
+ for (i = 0; i < RTSX_PHASE_MAX; i++) {
err = sd_tuning_rx_cmd(host, opcode, (u8)i);
if (err == 0)
raw_phase_map |= 1 << i;
diff --git a/include/linux/mfd/rtsx_pci.h b/include/linux/mfd/rtsx_pci.h
index 0ce7721..a383597 100644
--- a/include/linux/mfd/rtsx_pci.h
+++ b/include/linux/mfd/rtsx_pci.h
@@ -144,7 +144,7 @@
#define HOST_TO_DEVICE 0
#define DEVICE_TO_HOST 1

-#define MAX_PHASE 31
+#define RTSX_PHASE_MAX 32
#define RX_TUNING_CNT 3

/* SG descriptor */
--
1.7.9.5


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