[PATCH 1/4] mci: sdhci: provide sdhci_readx_poll_timeout helpers

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

The sdhci_readN accessors don't lend themselves for clean use with
readx_poll_timeout because they accept two arguments. Add
a sdhci-specific helper, so the sdhci drivers can cut down on the
timeout loop boilerplate.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 drivers/mci/sdhci.h | 51 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)

diff --git a/drivers/mci/sdhci.h b/drivers/mci/sdhci.h
index a307dc97cd9a..7ac32f1541b8 100644
--- a/drivers/mci/sdhci.h
+++ b/drivers/mci/sdhci.h
@@ -1,6 +1,8 @@
 #ifndef __MCI_SDHCI_H
 #define __MCI_SDHCI_H
 
+#include <pbl.h>
+
 #define SDHCI_DMA_ADDRESS					0x00
 #define SDHCI_BLOCK_SIZE__BLOCK_COUNT				0x04
 #define SDHCI_BLOCK_SIZE					0x04
@@ -144,4 +146,53 @@ void sdhci_set_cmd_xfer_mode(struct sdhci *host, struct mci_cmd *cmd,
 			     u32 *xfer);
 int sdhci_transfer_data(struct sdhci *sdhci, struct mci_data *data);
 
+/**
+ * sdhci_readx_poll_timeout -	Periodically poll an sdhci register until
+ *				a condition is met or a timeout occurs
+ * @bits: access width
+ * @sdhci: sdhci instance
+ * @reg: Register to poll
+ * @val: Variable to read the value into
+ * @cond: Break condition (usually involving @val)
+ * @timeout_us: Timeout in us, 0 means never timeout
+ *
+ * Returns 0 on success and -ETIMEDOUT upon a timeout. In either
+ * case, the last read value at @reg is stored in @val.
+ *
+ * When available, you'll probably want to use one of the specialized
+ * macros defined below rather than this macro directly.
+ *
+ * We do not have timing functions in the PBL, so ignore the timeout value and
+ * loop infinitely here.
+ *
+ * Based on readx_poll_timeout from <linux/iopoll.h>
+ */
+#define sdhci_readx_poll_timeout(bits, sdhci, reg, val, cond, timeout_us)	\
+({ \
+	uint64_t start; \
+	if (!IN_PBL && timeout_us) \
+		start = get_time_ns(); \
+	for (;;) { \
+		(val) = sdhci_read##bits(sdhci, reg); \
+		if (cond) \
+			break; \
+		if (!IN_PBL && timeout_us && \
+		    is_timeout(start, ((timeout_us) * USECOND))) { \
+			(val) = sdhci_read##bits(sdhci, reg); \
+			break; \
+		} \
+	} \
+	(cond) ? 0 : -ETIMEDOUT; \
+})
+
+
+#define sdhci_read8_poll_timeout(sdhci, reg, val, cond, timeout_us) \
+	sdhci_readx_poll_timeout(8, sdhci, reg, val, cond, timeout_us)
+
+#define sdhci_read16_poll_timeout(sdhci, reg, val, cond, timeout_us) \
+	sdhci_readx_poll_timeout(16, sdhci, reg, val, cond, timeout_us)
+
+#define sdhci_read32_poll_timeout(sdhci, reg, val, cond, timeout_us) \
+	sdhci_readx_poll_timeout(32, sdhci, reg, val, cond, timeout_us)
+
 #endif /* __MCI_SDHCI_H */
-- 
2.26.0.rc2


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