ram: stm32mp1: tuning: add timeout for polling BISTGSR.BDDONE

Avoid to block the tuning procedure on BIST error (not finished
BIST procedure) by adding a 1000us timeout on the polling of
BISTGSR.BDDONE executed to detect the end of BIST.

The normal duration of the BIST test is around 5us.

This patch also cleanup comments.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Acked-by: Patrice Chotard <patrice.chotard@st.com>

diff --git a/drivers/ram/stm32mp1/stm32mp1_tuning.c b/drivers/ram/stm32mp1/stm32mp1_tuning.c
index e3e6f0f..cab6cf0 100644 (file)
--- a/drivers/ram/stm32mp1/stm32mp1_tuning.c
+++ b/drivers/ram/stm32mp1/stm32mp1_tuning.c
@@ -8,6 +8,7 @@
 #include <ram.h>
 #include <reset.h>
 #include <asm/io.h>
+#include <linux/iopoll.h>
 
 #include "stm32mp1_ddr_regs.h"
 #include "stm32mp1_ddr.h"
@@ -246,6 +247,8 @@ static void BIST_test(struct stm32mp1_ddrphy *phy, u8 byte,
        bool result = true; /* BIST_SUCCESS */
        u32 cnt = 0;
        u32 error = 0;
+       u32 val;
+       int ret;
 
        bist->test_result = true;
 
@@ -274,27 +277,29 @@ run:
                        0x00000001);
        /* Write BISTRR.BINST = 3?b001; */
 
-       /* Wait for a number of CTL clocks before reading BIST register*/
-       /* Wait 300 ctl_clk cycles;  ... IS it really needed?? */
-       /* Perform BIST Instruction Stop*/
-       /* Write BISTRR.BINST = 3?b010;*/
-
-       /* poll on BISTGSR.BDONE. If 0, wait.  ++TODO Add timeout */
-       while (!(readl(&phy->bistgsr) & DDRPHYC_BISTGSR_BDDONE))
-               ;
-
-       /*Check if received correct number of words*/
-       /* if (Read BISTWCSR.DXWCNT = Read BISTWCR.BWCNT) */
-       if (((readl(&phy->bistwcsr)) >> DDRPHYC_BISTWCSR_DXWCNT_SHIFT) ==
-           readl(&phy->bistwcr)) {
-               /*Determine if there is a data comparison error*/
-               /* if (Read BISTGSR.BDXERR = 1?b0) */
-               if (readl(&phy->bistgsr) & DDRPHYC_BISTGSR_BDXERR)
-                       result = false; /* BIST_FAIL; */
-               else
-                       result = true; /* BIST_SUCCESS; */
-       } else {
+       /* poll on BISTGSR.BDONE and wait max 1000 us */
+       ret = readl_poll_timeout(&phy->bistgsr, val,
+                                val & DDRPHYC_BISTGSR_BDDONE, 1000);
+
+       if (ret < 0) {
+               printf("warning: BIST timeout\n");
                result = false; /* BIST_FAIL; */
+               /*Perform BIST Stop */
+               clrsetbits_le32(&phy->bistrr, 0x00000007, 0x00000002);
+       } else {
+               /*Check if received correct number of words*/
+               /* if (Read BISTWCSR.DXWCNT = Read BISTWCR.BWCNT) */
+               if (((readl(&phy->bistwcsr)) >> DDRPHYC_BISTWCSR_DXWCNT_SHIFT)
+                   == readl(&phy->bistwcr)) {
+                       /*Determine if there is a data comparison error*/
+                       /* if (Read BISTGSR.BDXERR = 1?b0) */
+                       if (readl(&phy->bistgsr) & DDRPHYC_BISTGSR_BDXERR)
+                               result = false; /* BIST_FAIL; */
+                       else
+                               result = true; /* BIST_SUCCESS; */
+               } else {
+                       result = false; /* BIST_FAIL; */
+               }
        }
 
        /* loop while success */