scsi: ufs: core: Poll HCS.UCRDY before issuing a UIC command

With auto hibern8 enabled, UIC could be busy processing a hibern8 operation
and the HCI would reports UIC not ready for a short while through
HCS.UCRDY. The UFS driver doesn't currently handle this situation. The
UFSHCI spec specifies UCRDY like this: whether the host controller is ready
to process UIC COMMAND

The 'ready' could be seen as many different meanings. If the meaning
includes not processing any request from HCI, processing a hibern8
operation can be 'not ready'. In this situation, the driver needs to wait
until the operations is completed.

Signed-off-by: Kiwoong Kim <[email protected]>
Link: https://lore.kernel.org/r/550484ffb66300bdcec63d3e304dfd55cb432f1f.1693790060.git.kwmad.kim@samsung.com
Reviewed-by: Adrian Hunter <[email protected]>
Reviewed-by: Chanwoo Lee <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

Author: Kiwoong Kim

drivers/ufs/core/ufshcd.c

@@ -22,6 +22,7 @@
 #include <linux/module.h>
 #include <linux/regulator/consumer.h>
 #include <linux/sched/clock.h>
+#include <linux/iopoll.h>
 #include <scsi/scsi_cmnd.h>
 #include <scsi/scsi_dbg.h>
 #include <scsi/scsi_driver.h>
@@ -2299,7 +2300,11 @@ static inline int ufshcd_hba_capabilities(struct ufs_hba *hba)
  */
 static inline bool ufshcd_ready_for_uic_cmd(struct ufs_hba *hba)
 {
-	return ufshcd_readl(hba, REG_CONTROLLER_STATUS) & UIC_COMMAND_READY;
+	u32 val;
+	int ret = read_poll_timeout(ufshcd_readl, val, val & UIC_COMMAND_READY,
+				    500, UIC_CMD_TIMEOUT * 1000, false, hba,
+				    REG_CONTROLLER_STATUS);
+	return ret == 0 ? true : false;
 }
 
 /**