Add function to poll register waiting for specific bit(s). Similar functions are implemented in few drivers - they are almost identical and can be generalized. Signed-off-by: Mateusz Kulikowski mateusz.kulikowski@gmail.com ---
include/wait_bit.h | 71 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 71 insertions(+) create mode 100644 include/wait_bit.h
diff --git a/include/wait_bit.h b/include/wait_bit.h new file mode 100644 index 0000000..061a2db --- /dev/null +++ b/include/wait_bit.h @@ -0,0 +1,71 @@ +/* + * Wait for bit with timeout and ctrlc + * + * (C) Copyright 2015 Mateusz Kulikowski mateusz.kulikowski@gmail.com + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#ifndef __WAIT_BIT_H +#define __WAIT_BIT_H + +#include <common.h> +#include <console.h> +#include <asm/errno.h> +#include <asm/io.h> + +/** + * wait_for_bit() 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 prefix Prefix added to timeout messagge (message visible only + * with debug enabled) + * @param reg Register that will be read (using readl()) + * @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, -ETIMEDOUT or -EINTR on failure + */ +static inline int wait_for_bit(const char *prefix, const u32 *reg, + const u32 mask, const bool set, + const unsigned int timeout_ms, + const bool breakable) +{ + u32 val; + unsigned long start = get_timer(0); + + while (1) { + val = readl(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); + } + + debug("%s: Timeout (reg=%p mask=%08x wait_set=%i)\n", prefix, reg, mask, + set); + + return -ETIMEDOUT; +} + + +#endif