[U-Boot] [PATCH] wait_bit: add big endian version of wait_for_bit function

[Tom Rini <trini@konsulko.com>]

On Tue, Jan 02, 2018 at 10:37:31AM +0100, Álvaro Fernández Rojas wrote:
> Hello Tom,
> 
> 
> El 01/01/2018 a las 14:41, Tom Rini escribió:
> >On Sat, Dec 30, 2017 at 11:12:36AM +0100, Álvaro Fernández Rojas wrote:
> >
> >>The only difference with the existing wait_for_bit function is the fact that
> >>wait_for_bit_be expects the register size to be read.
> >>
> >>Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
> >>---
> >>  include/wait_bit.h | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
> >>  1 file changed, 69 insertions(+)
> >>
> >>diff --git a/include/wait_bit.h b/include/wait_bit.h
> >>index 06ad43a122..828fdcda02 100644
> >>--- a/include/wait_bit.h
> >>+++ b/include/wait_bit.h
> >>@@ -69,5 +69,74 @@ static inline int wait_for_bit(const char *prefix, const u32 *reg,
> >>  	return -ETIMEDOUT;
> >>  }
> >>+/**
> >>+ * wait_for_bit_be()	waits for bit set/cleared in BE 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 prefix	Prefix added to timeout messagge (message visible only
> >>+ *			with debug enabled)
> >>+ * @param reg		Register that will be read (using read_be())
> >>+ * @param size		Size of the register that will be read
> >>+ * @param mask		Bit(s) of register that must be active
> >>+ * @param set		Selects wait condition (bit set or clear)
> >>+ * @param timeout_ms	Timeout (in miliseconds)
> >>+ * @param breakable	Enables CTRL-C interruption
> >>+ * @return		0 on success, -EINVAL, -ETIMEDOUT or -EINTR on failure
> >>+ */
> >>+static inline int wait_for_bit_be(const char *prefix,
> >>+				  const u32 *reg, const u8 size,
> >>+				  const u32 mask, const bool set,
> >>+				  const unsigned int timeout_ms,
> >>+				  const bool breakable)
> >>+{
> >>+	u32 val;
> >>+	unsigned long start = get_timer(0);
> >>+
> >>+	while (1) {
> >>+		switch(size)
> >>+		{
> >>+			case 8:
> >>+				val = readb_be(reg);
> >>+				break;
> >>+			case 16:
> >>+				val = readw_be(reg);
> >>+				break;
> >>+			case 32:
> >>+				val = readl_be(reg);
> >>+				break;
> >>+			default:
> >>+				debug("%s: invalid size %u\n", prefix, size);
> >>+				return -EINVAL;
> >>+		}
> >>+
> >>+		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=%08x wait_set=%i)\n", prefix, reg, mask,
> >>+	      set);
> >>+
> >>+	return -ETIMEDOUT;
> >>+}
> >Where is this used?  Thanks!
> I was planning on using this for both brcm63xx SPI drivers, as stated here:
> https://lists.denx.de/pipermail/u-boot/2017-December/315263.html
> https://lists.denx.de/pipermail/u-boot/2017-December/315264.html
> 
> Maybe it would be better to define a macro and use it for both LE/BE, with
> functions like:
> wait_for_bit_8
> wait_for_bit_le16/wait_for_bit_be16
> wait_for_bit_le32/wait_for_bit_be32
> 
> What do you think?

Whatever feels cleaner with the rest of your patches is fine.  But
please post it as part of the series.  Thanks!

-- 
Tom
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