On 2022-08-25 at 16:13:42 +0200, Johannes Zink wrote:
> Measurements showed that some FPGAs take significantly longer than the
> default wait function supplied. The datasheet inidicates up to 30
> seconds erase times for some MachXO2 FPGAs, depending on the number of
> LUTs (and the corresponding configuration flash size).
>
> Signed-off-by: Johannes Zink <j.zink@xxxxxxxxxxxxxx>
> ---
> drivers/fpga/machxo2-common.c | 28 ++++++++++++++++++++++++++--
> 1 file changed, 26 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/fpga/machxo2-common.c b/drivers/fpga/machxo2-common.c
> index ccf9a50fc590..e8967cdee2c6 100644
> --- a/drivers/fpga/machxo2-common.c
> +++ b/drivers/fpga/machxo2-common.c
> @@ -17,6 +17,8 @@
> #include <linux/module.h>
> #include <linux/of.h>
> #include <linux/property.h>
> +#include <linux/iopoll.h>
> +#include <linux/time.h>
> #include "machxo2-common.h"
>
> #define MACHXO2_LOW_DELAY_USEC 5
> @@ -24,6 +26,8 @@
> #define MACHXO2_REFRESH_USEC 4800
> #define MACHXO2_MAX_BUSY_LOOP 128
> #define MACHXO2_MAX_REFRESH_LOOP 16
> +#define MACHXO2_MAX_ERASE_USEC (30 * USEC_PER_SEC)
> +#define MACHXO2_ERASE_USEC_SLEEP (20 * USEC_PER_MSEC)
>
> #define MACHXO2_PAGE_SIZE 16
> #define MACHXO2_BUF_SIZE (MACHXO2_PAGE_SIZE + 4)
> @@ -54,6 +58,18 @@
> #define ISC_ERASE_FEATURE_ROW BIT(17)
> #define ISC_ERASE_UFM BIT(19)
>
> +static inline int machxo2_wait_until_not_busy_timeout(struct machxo2_common_priv *priv)
> +{
> + int ret, pollret;
> + u32 status = MACHXO2_BUSY;
> +
> + pollret = read_poll_timeout(priv->get_status, ret,
> + (ret && ret != -EAGAIN) || !(status & MACHXO2_BUSY),
> + MACHXO2_ERASE_USEC_SLEEP, MACHXO2_MAX_ERASE_USEC,
> + true, priv, &status);
Why just taking care of erase timeout? I see the busy wait in many
places.
> +
> + return ret ?: pollret;
> +}
>
> static inline u8 get_err(u32 status)
> {
> @@ -114,6 +130,12 @@ static int machxo2_cleanup(struct fpga_manager *mgr)
> if (ret)
> goto fail;
>
> + ret = machxo2_wait_until_not_busy_timeout(priv);
> + if (ret) {
> + dev_err(&mgr->dev, "Erase operation failed (%d)", ret);
> + goto fail;
> + }
> +
> ret = machxo2_wait_until_not_busy(priv);
Is this line still needed?
> if (ret)
> goto fail;
> @@ -192,9 +214,11 @@ static int machxo2_write_init(struct fpga_manager *mgr,
> if (ret)
> goto fail;
>
> - ret = machxo2_wait_until_not_busy(priv);
> - if (ret)
> + ret = machxo2_wait_until_not_busy_timeout(priv);
> + if (ret) {
> + dev_err(&mgr->dev, "Erase operation failed (%d)", ret);
> goto fail;
> + }
>
> priv->get_status(priv, &status);
> if (status & MACHXO2_FAIL) {
> --
> 2.30.2
>
