mmc: rtsx: modify phase searching method for tuning

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

Signed-off-by: Micky Ching <micky_ching@realsil.com.cn>
Signed-off-by: Chris Ball <chris@printf.net>

1 files changed, 32 insertions, 80 deletions

diff --git a/drivers/mmc/host/rtsx_pci_sdmmc.c b/drivers/mmc/host/rtsx_pci_sdmmc.c
index cc80e3119d1d..0b9ded13a3ae 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;