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>

diff --git a/drivers/mmc/host/rtsx_pci_sdmmc.c b/drivers/mmc/host/rtsx_pci_sdmmc.c
index cc80e3119d1de248648413434070f04c78a69bd8..0b9ded13a3ae89d72a94e7e8e075f62496483f0e 100644 (file)
--- 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 0ce7721055081b3a75e16ea9b485c01b7e83a1f8..a3835976f7c639e8f24e17cf2df6dc495f07fae4 100644 (file)
--- 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 */