adi_v5_jtag.c: Avoid infinite recursion in jtagdp_transaction_endcheck()

[fw/openocd] / src / target / adi_v5_jtag.c

diff --git a/src/target/adi_v5_jtag.c b/src/target/adi_v5_jtag.c
index 8731a1a0970e6e9686108d8d114a36b71bdc1cb0..9f37bd553d841080b8c416eceed2c553d2f1e524 100644 (file)
--- a/src/target/adi_v5_jtag.c
+++ b/src/target/adi_v5_jtag.c
@@ -40,7 +40,6 @@
 #include "arm_adi_v5.h"
 #include <helper/time_support.h>
 
-
 /* JTAG instructions/registers for JTAG-DP and SWJ-DP */
 #define JTAG_DP_ABORT          0x8
 #define JTAG_DP_DPACC          0xA
@@ -191,22 +190,30 @@ static int jtagdp_transaction_endcheck(struct adiv5_dap *dap)
 
        /* too expensive to call keep_alive() here */
 
-#if 0
-       /* Danger!!!! BROKEN!!!! */
-       adi_jtag_scan_inout_check_u32(dap, JTAG_DP_DPACC,
-                       DP_CTRL_STAT, DPAP_READ, 0, &ctrlstat);
-       /* Danger!!!! BROKEN!!!! Why will jtag_execute_queue() fail here????
-       R956 introduced the check on return value here and now Michael Schwingen reports
-       that this code no longer works....
-
-       https://lists.berlios.de/pipermail/openocd-development/2008-September/003107.html
-       */
-       if ((retval = jtag_execute_queue()) != ERROR_OK)
-       {
-               LOG_ERROR("BUG: Why does this fail the first time????");
-       }
-       /* Why??? second time it works??? */
-#endif
+       /* Here be dragons!
+        *
+        * It is easy to be in a JTAG clock range where the target
+        * is not operating in a stable fashion. This happens
+        * for a few reasons:
+        *
+        * - the user may construct a simple test case to try to see
+        * if a higher JTAG clock works to eke out more performance.
+        * This simple case may pass, but more complex situations can
+        * fail.
+        *
+        * - The mostly works JTAG clock rate and the complete failure
+        * JTAG clock rate may be as much as 2-4x apart. This seems
+        * to be especially true on RC oscillator driven parts.
+        *
+        * So: even if calling adi_jtag_scan_inout_check_u32() multiple
+        * times here seems to "make things better here", it is just
+        * hiding problems with too high a JTAG clock.
+        *
+        * Note that even if some parts have RCLK/RTCK, that doesn't
+        * mean that RCLK/RTCK is the *correct* rate to run the JTAG
+        * interface at, i.e. RCLK/RTCK rates can be "too high", especially
+        * before the RC oscillator phase is not yet complete.
+        */
 
        /* Post CTRL/STAT read; discard any previous posted read value
         * but collect its ACK status.
@@ -215,22 +222,19 @@ static int jtagdp_transaction_endcheck(struct adiv5_dap *dap)
                        DP_CTRL_STAT, DPAP_READ, 0, &ctrlstat);
        if (retval != ERROR_OK)
                return retval;
-       if ((retval = jtag_execute_queue()) != ERROR_OK)
+       retval = jtag_execute_queue();
+       if (retval != ERROR_OK)
                return retval;
 
        dap->ack = dap->ack & 0x7;
 
        /* common code path avoids calling timeval_ms() */
-       if (dap->ack != JTAG_ACK_OK_FAULT)
-       {
+       if (dap->ack != JTAG_ACK_OK_FAULT) {
                long long then = timeval_ms();
 
-               while (dap->ack != JTAG_ACK_OK_FAULT)
-               {
-                       if (dap->ack == JTAG_ACK_WAIT)
-                       {
-                               if ((timeval_ms()-then) > 1000)
-                               {
+               while (dap->ack != JTAG_ACK_OK_FAULT) {
+                       if (dap->ack == JTAG_ACK_WAIT) {
+                               if ((timeval_ms()-then) > 1000) {
                                        /* NOTE:  this would be a good spot
                                         * to use JTAG_DP_ABORT.
                                         */
@@ -239,9 +243,7 @@ static int jtagdp_transaction_endcheck(struct adiv5_dap *dap)
                                                "in JTAG-DP transaction");
                                        return ERROR_JTAG_DEVICE_ERROR;
                                }
-                       }
-                       else
-                       {
+                       } else {
                                LOG_WARNING("Invalid ACK %#x "
                                                "in JTAG-DP transaction",
                                                dap->ack);
@@ -252,7 +254,8 @@ static int jtagdp_transaction_endcheck(struct adiv5_dap *dap)
                                        DP_CTRL_STAT, DPAP_READ, 0, &ctrlstat);
                        if (retval != ERROR_OK)
                                return retval;
-                       if ((retval = dap_run(dap)) != ERROR_OK)
+                       retval = jtag_execute_queue();
+                       if (retval != ERROR_OK)
                                return retval;
                        dap->ack = dap->ack & 0x7;
                }
@@ -261,18 +264,14 @@ static int jtagdp_transaction_endcheck(struct adiv5_dap *dap)
        /* REVISIT also STICKYCMP, for pushed comparisons (nyet used) */
 
        /* Check for STICKYERR and STICKYORUN */
-       if (ctrlstat & (SSTICKYORUN | SSTICKYERR))
-       {
+       if (ctrlstat & (SSTICKYORUN | SSTICKYERR)) {
                LOG_DEBUG("jtag-dp: CTRL/STAT error, 0x%" PRIx32, ctrlstat);
                /* Check power to debug regions */
-               if ((ctrlstat & 0xf0000000) != 0xf0000000)
-               {
+               if ((ctrlstat & 0xf0000000) != 0xf0000000) {
                        retval = ahbap_debugport_init(dap);
                        if (retval != ERROR_OK)
                                return retval;
-               }
-               else
-               {
+               } else {
                        uint32_t mem_ap_csw, mem_ap_tar;
 
                        /* Maybe print information about last intended
@@ -306,7 +305,8 @@ static int jtagdp_transaction_endcheck(struct adiv5_dap *dap)
                                        DP_CTRL_STAT, DPAP_READ, 0, &ctrlstat);
                        if (retval != ERROR_OK)
                                return retval;
-                       if ((retval = dap_run(dap)) != ERROR_OK)
+                       retval = jtag_execute_queue();
+                       if (retval != ERROR_OK)
                                return retval;
 
                        LOG_DEBUG("jtag-dp: CTRL/STAT 0x%" PRIx32, ctrlstat);
@@ -321,13 +321,15 @@ static int jtagdp_transaction_endcheck(struct adiv5_dap *dap)
                        if (retval != ERROR_OK)
                                return retval;
 
-                       if ((retval = dap_run(dap)) != ERROR_OK)
+                       retval = jtag_execute_queue();
+                       if (retval != ERROR_OK)
                                return retval;
                        LOG_ERROR("MEM_AP_CSW 0x%" PRIx32 ", MEM_AP_TAR 0x%"
                                        PRIx32, mem_ap_csw, mem_ap_tar);
 
                }
-               if ((retval = dap_run(dap)) != ERROR_OK)
+               retval = jtag_execute_queue();
+               if (retval != ERROR_OK)
                        return retval;
                return ERROR_JTAG_DEVICE_ERROR;
        }
@@ -384,7 +386,7 @@ static int jtag_ap_q_bankselect(struct adiv5_dap *dap, unsigned reg)
                return ERROR_OK;
        dap->ap_bank_value = select_ap_bank;
 
-       select_ap_bank |= dap->apsel;
+       select_ap_bank |= dap->ap_current;
 
        return jtag_dp_q_write(dap, DP_SELECT, select_ap_bank);
 }