arm: socfpga: scan: Clean up scan_chain_engine_is_idle()

Rework this function so it's clear that it is only polling for certain
bits to be cleared. Add kerneldoc. Fix it's return value to be either
0 on success and -ETIMEDOUT on error and propagate this through the
scan manager code.

Signed-off-by: Marek Vasut <marex@denx.de>
Acked-by: Dinh Nguyen <dinguyen@opensource.altera.com>

diff --git a/arch/arm/mach-socfpga/include/mach/scan_manager.h b/arch/arm/mach-socfpga/include/mach/scan_manager.h
index 94ad50b..ddf8790 100644 (file)
--- a/arch/arm/mach-socfpga/include/mach/scan_manager.h
+++ b/arch/arm/mach-socfpga/include/mach/scan_manager.h
@@ -59,15 +59,6 @@ struct socfpga_scan_manager {
 /* Position of second command byte for TDI_TDO packet */
 #define TDI_TDO_HEADER_SECOND_BYTE_SHIFT       8
 
-/*
- * Maximum polling loop to wait for IO scan chain engine
- * becomes idle to prevent infinite loop
- */
-#define SCAN_MAX_DELAY                         100
-
-#define SCANMGR_STAT_ACTIVE_GET(x) (((x) & 0x80000000) >> 31)
-#define SCANMGR_STAT_WFIFOCNT_GET(x) (((x) & 0x70000000) >> 28)
-
 int scan_mgr_configure_iocsr(void);
 int iocsr_get_config_table(const unsigned int chain_id,
                           const unsigned long **table,

diff --git a/arch/arm/mach-socfpga/scan_manager.c b/arch/arm/mach-socfpga/scan_manager.c
index ec0c630..3f244b9 100644 (file)
--- a/arch/arm/mach-socfpga/scan_manager.c
+++ b/arch/arm/mach-socfpga/scan_manager.c
@@ -5,10 +5,22 @@
  */
 
 #include <common.h>
+#include <errno.h>
 #include <asm/io.h>
 #include <asm/arch/freeze_controller.h>
 #include <asm/arch/scan_manager.h>
 
+/*
+ * Maximum polling loop to wait for IO scan chain engine becomes idle
+ * to prevent infinite loop. It is important that this is NOT changed
+ * to delay using timer functions, since at the time this function is
+ * called, timer might not yet be inited.
+ */
+#define SCANMGR_MAX_DELAY              100
+
+#define SCANMGR_STAT_ACTIVE            (1 << 31)
+#define SCANMGR_STAT_WFIFOCNT_MASK     0x70000000
+
 DECLARE_GLOBAL_DATA_PTR;
 
 static const struct socfpga_scan_manager *scan_manager_base =
@@ -16,26 +28,26 @@ static const struct socfpga_scan_manager *scan_manager_base =
 static const struct socfpga_freeze_controller *freeze_controller_base =
                (void *)(SOCFPGA_SYSMGR_ADDRESS + SYSMGR_FRZCTRL_ADDRESS);
 
-/*
+/**
+ * scan_chain_engine_is_idle() - Check if the JTAG scan chain is idle
+ * @max_iter:  Maximum number of iterations to wait for idle
+ *
  * Function to check IO scan chain engine status and wait if the engine is
  * is active. Poll the IO scan chain engine till maximum iteration reached.
  */
-static inline uint32_t scan_chain_engine_is_idle(uint32_t max_iter)
+static u32 scan_chain_engine_is_idle(u32 max_iter)
 {
-       uint32_t scanmgr_status;
-
-       scanmgr_status = readl(&scan_manager_base->stat);
+       const u32 mask = SCANMGR_STAT_ACTIVE | SCANMGR_STAT_WFIFOCNT_MASK;
+       u32 status;
 
-       /* Poll the engine until the scan engine is inactive */
-       while (SCANMGR_STAT_ACTIVE_GET(scanmgr_status) ||
-             (SCANMGR_STAT_WFIFOCNT_GET(scanmgr_status) > 0)) {
-               max_iter--;
-               if (max_iter > 0)
-                       scanmgr_status = readl(&scan_manager_base->stat);
-               else
+       /* Poll the engine until the scan engine is inactive. */
+       do {
+               status = readl(&scan_manager_base->stat);
+               if (!(status & mask))
                        return 0;
-       }
-       return 1;
+       } while (max_iter--);
+
+       return -ETIMEDOUT;
 }
 
 /**
@@ -70,8 +82,9 @@ static int scan_mgr_io_scan_chain_prg(const unsigned int io_scan_chain_id)
         * Check if the scan chain engine is inactive and the
         * WFIFO is empty before enabling the IO scan chain
         */
-       if (!scan_chain_engine_is_idle(SCAN_MAX_DELAY))
-               return 1;
+       ret = scan_chain_engine_is_idle(SCANMGR_MAX_DELAY);
+       if (ret)
+               return ret;
 
        /*
         * Enable IO Scan chain based on scan chain id
@@ -114,7 +127,8 @@ static int scan_mgr_io_scan_chain_prg(const unsigned int io_scan_chain_id)
                 * Check if the scan chain engine has completed the
                 * IO scan chain data shifting
                 */
-               if (!scan_chain_engine_is_idle(SCAN_MAX_DELAY))
+               ret = scan_chain_engine_is_idle(SCANMGR_MAX_DELAY);
+               if (ret)
                        goto error;
        }
 
@@ -185,7 +199,8 @@ static int scan_mgr_io_scan_chain_prg(const unsigned int io_scan_chain_id)
                 * Check if the scan chain engine has completed the
                 * IO scan chain data shifting
                 */
-               if (!scan_chain_engine_is_idle(SCAN_MAX_DELAY))
+               ret = scan_chain_engine_is_idle(SCANMGR_MAX_DELAY);
+               if (ret)
                        goto error;
        }
 
@@ -196,7 +211,7 @@ static int scan_mgr_io_scan_chain_prg(const unsigned int io_scan_chain_id)
 error:
        /* Disable IO Scan chain when error detected */
        clrbits_le32(&scan_manager_base->en, 1 << io_scan_chain_id);
-       return 1;
+       return ret;
 }
 
 int scan_mgr_configure_iocsr(void)