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authorIvan Bornyakov <i.bornyakov@metrotek.ru>2022-12-30 12:29:21 +0300
committerXu Yilun <yilun.xu@intel.com>2023-01-28 18:20:30 +0300
commit88e705697e801299a13ecaf2ba54599964fe711c (patch)
treed531ba682ac458b2a7cf59335a2b00a5c71b72ee /drivers/fpga
parent1da53d23a41c5f77963984d8da5623ed56918ada (diff)
downloadlinux-88e705697e801299a13ecaf2ba54599964fe711c.tar.xz
fpga: microchip-spi: rewrite status polling in a time measurable way
Original busy loop with retries count in mpf_poll_status() is not too reliable, as it takes different times on different systems. Replace it with read_poll_timeout() macro. While at it, fix polling stop condition to met function's original intention declared in the comment. The issue with original polling stop condition is that it stops if any of mask bits is set, while intention was to stop if all mask bits is set. This was not noticible because only MPF_STATUS_READY is passed as mask argument and it is BIT(1). Fixes: 5f8d4a900830 ("fpga: microchip-spi: add Microchip MPF FPGA manager") Signed-off-by: Ivan Bornyakov <i.bornyakov@metrotek.ru> Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Acked-by: Conor Dooley <conor.dooley@microchip.com> Acked-by: Xu Yilun <yilun.xu@intel.com> Link: https://lore.kernel.org/r/20221230092922.18822-3-i.bornyakov@metrotek.ru Signed-off-by: Xu Yilun <yilun.xu@intel.com>
Diffstat (limited to 'drivers/fpga')
-rw-r--r--drivers/fpga/microchip-spi.c32
1 files changed, 17 insertions, 15 deletions
diff --git a/drivers/fpga/microchip-spi.c b/drivers/fpga/microchip-spi.c
index bb69f5beefe7..137fafdf57a6 100644
--- a/drivers/fpga/microchip-spi.c
+++ b/drivers/fpga/microchip-spi.c
@@ -6,6 +6,7 @@
#include <asm/unaligned.h>
#include <linux/delay.h>
#include <linux/fpga/fpga-mgr.h>
+#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/spi/spi.h>
@@ -33,7 +34,7 @@
#define MPF_BITS_PER_COMPONENT_SIZE 22
-#define MPF_STATUS_POLL_RETRIES 10000
+#define MPF_STATUS_POLL_TIMEOUT (2 * USEC_PER_SEC)
#define MPF_STATUS_BUSY BIT(0)
#define MPF_STATUS_READY BIT(1)
#define MPF_STATUS_SPI_VIOLATION BIT(2)
@@ -194,24 +195,25 @@ static int mpf_ops_parse_header(struct fpga_manager *mgr,
return 0;
}
-/* Poll HW status until busy bit is cleared and mask bits are set. */
static int mpf_poll_status(struct mpf_priv *priv, u8 mask)
{
- int status, retries = MPF_STATUS_POLL_RETRIES;
+ int ret, status;
- while (retries--) {
- status = mpf_read_status(priv);
- if (status < 0)
- return status;
-
- if (status & MPF_STATUS_BUSY)
- continue;
-
- if (!mask || (status & mask))
- return status;
- }
+ /*
+ * Busy poll HW status. Polling stops if any of the following
+ * conditions are met:
+ * - timeout is reached
+ * - mpf_read_status() returns an error
+ * - busy bit is cleared AND mask bits are set
+ */
+ ret = read_poll_timeout(mpf_read_status, status,
+ (status < 0) ||
+ ((status & (MPF_STATUS_BUSY | mask)) == mask),
+ 0, MPF_STATUS_POLL_TIMEOUT, false, priv);
+ if (ret < 0)
+ return ret;
- return -EBUSY;
+ return status;
}
static int mpf_spi_write(struct mpf_priv *priv, const void *buf, size_t buf_size)