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 <[email protected]> ---
include/wait_bit.h | 34 ++++++++++++++++++++++++++++++++++ lib/Kconfig | 4 ++++ lib/Makefile | 1 + lib/wait_bit.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 83 insertions(+) create mode 100644 include/wait_bit.h create mode 100644 lib/wait_bit.c diff --git a/include/wait_bit.h b/include/wait_bit.h new file mode 100644 index 0000000..7dbfa1a --- /dev/null +++ b/include/wait_bit.h @@ -0,0 +1,34 @@ +/* + * Wait for bit with timeout and ctrlc + * + * (C) Copyright 2015 Mateusz Kulikowski <[email protected]> + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#ifndef __WAIT_BIT_H +#define __WAIT_BIT_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 Timeout (in miliseconds) + * @param breakable Enables CTRL-C interruption + * @return 0 on success, -ETIMEDOUT or -EINTR on failure + */ +int wait_for_bit(const char *prefix, u32 *reg, const u32 mask, bool set, + unsigned int timeout, bool breakable); + +#endif diff --git a/lib/Kconfig b/lib/Kconfig index 9d580e4..5977fc6 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -137,6 +137,10 @@ config ERRNO_STR - if errno is null or positive number - a pointer to "Success" message - if errno is negative - a pointer to errno related message +config LIB_WAIT_BIT + bool + default n + source lib/efi/Kconfig endmenu diff --git a/lib/Makefile b/lib/Makefile index 1f1ff6f..437f937 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -81,6 +81,7 @@ obj-y += time.o obj-$(CONFIG_TRACE) += trace.o obj-$(CONFIG_LIB_UUID) += uuid.o obj-$(CONFIG_LIB_RAND) += rand.o +obj-$(CONFIG_LIB_WAIT_BIT) += wait_bit.o ifdef CONFIG_SPL_BUILD # SPL U-Boot may use full-printf, tiny-printf or none at all diff --git a/lib/wait_bit.c b/lib/wait_bit.c new file mode 100644 index 0000000..3c78eac --- /dev/null +++ b/lib/wait_bit.c @@ -0,0 +1,44 @@ +/* + * Wait for bit interruptible by timeout or ctrlc + * + * (C) Copyright 2015 Mateusz Kulikowski <[email protected]> + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#include <common.h> +#include <console.h> +#include <asm/io.h> +#include <asm/errno.h> + +int wait_for_bit(const char *prefix, u32 *reg, const u32 mask, bool set, + unsigned int timeout, 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) + 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; +} -- 2.5.0 _______________________________________________ U-Boot mailing list [email protected] http://lists.denx.de/mailman/listinfo/u-boot
