[U-Boot] [PATCH v7 01/13] wait_bit: add 8/16/32 BE/LE versions of wait_for_bit

Álvaro Fernández Rojas
2018-01-10T20:26:35Z

Add 8/16/32 bits and BE/LE versions of wait_for_bit.
This is needed for reading registers that are not aligned to 32 bits, and for
Big Endian platforms.

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
---
v7: Introduce changes suggested by Daniel Schwierzeck:
- Use const void* reg for compatibility with 64 bit systems.
- Remove prefix and use __func__ instead.
v6: Introduce changes suggested by Jagan Teki:
- Switch to wait_for_bit instead of infinite loop.

include/wait_bit.h | 61 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 61 insertions(+)

diff --git a/include/wait_bit.h b/include/wait_bit.h
index 06ad43a122..bde6d2cfc3 100644
--- a/include/wait_bit.h
+++ b/include/wait_bit.h
@@ -69,5 +69,66 @@ static inline int wait_for_bit(const char *prefix, const u32 *reg,
return -ETIMEDOUT;
}

+/**
+ * wait_for_bit_x() waits for bit set/cleared in register
+ *
+ * Function polls register waiting for specific bit(s) change
+ * (either 0->1 or 1->0). It can fail under two conditions:
+ * - Timeout
+ * - User interaction (CTRL-C)
+ * Function succeeds only if all bits of masked register are set/cleared
+ * (depending on set option).
+ *
+ * @param reg Register that will be read (using read_x())
+ * @param mask Bit(s) of register that must be active
+ * @param set Selects wait condition (bit set or clear)
+ * @param timeout_ms Timeout (in milliseconds)
+ * @param breakable Enables CTRL-C interruption
+ * @return 0 on success, -ETIMEDOUT or -EINTR on failure
+ */
+
+#define BUILD_WAIT_FOR_BIT(sfx, type, read) \
+ \
+static inline int wait_for_bit_##sfx(const void *reg, \
+ const type mask, \
+ const bool set, \
+ const unsigned int timeout_ms, \
+ const bool breakable) \
+{ \
+ type val; \
+ unsigned long start = get_timer(0); \
+ \
+ while (1) { \
+ val = read(reg); \
+ \
+ if (!set) \
+ val = ~val; \
+ \
+ if ((val & mask) == mask) \
+ return 0; \
+ \
+ if (get_timer(start) > timeout_ms) \
+ break; \
+ \
+ if (breakable && ctrlc()) { \
+ puts("Abort\n"); \
+ return -EINTR; \
+ } \
+ \
+ udelay(1); \
+ WATCHDOG_RESET(); \
+ } \
+ \
+ debug("%s: Timeout (reg=%p mask=%x wait_set=%i)\n", __func__, \
+ reg, mask, set); \
+ \
+ return -ETIMEDOUT; \
+}
+
+BUILD_WAIT_FOR_BIT(8, u8, readb)
+BUILD_WAIT_FOR_BIT(le16, u16, readw)
+BUILD_WAIT_FOR_BIT(be16, u16, readw_be)
+BUILD_WAIT_FOR_BIT(le32, u32, readl)
+BUILD_WAIT_FOR_BIT(be32, u32, readl_be)

#endif
--
2.11.0