Problem statement:

Due to hardware errata in Aero controllers, reads to certain
fusion registers could intermittently return all zeroes.
This behavior is transient in nature and subsequent reads will return
valid value.

Fix:
For Aero controllers, any read will retry the read operations
from certain registers for maximum three times, if read returns zero.

Submitted by: Sumit Saxena <sumit.saxena@broadcom.com>
Reviewed by:  Kashyap Desai <Kashyap.Desai@broadcom.com>
Approved by:  ken
MFC after:  3 days
Sponsored by:   Broadcom Inc

1 files changed, 41 insertions, 23 deletions

diff --git a/sys/dev/mrsas/mrsas.c b/sys/dev/mrsas/mrsas.c
index 1727434fc529..8b643d679f78 100644
--- a/sys/dev/mrsas/mrsas.c
+++ b/sys/dev/mrsas/mrsas.c
@@ -95,6 +95,8 @@ mrsas_get_pd_info(struct mrsas_softc *sc, u_int16_t device_id);
 static struct mrsas_softc *
 mrsas_get_softc_instance(struct cdev *dev,
     u_long cmd, caddr_t arg);
+u_int32_t
+mrsas_read_reg_with_retries(struct mrsas_softc *sc, int offset);
 u_int32_t mrsas_read_reg(struct mrsas_softc *sc, int offset);
 u_int8_t
 mrsas_build_mptmfi_passthru(struct mrsas_softc *sc,
@@ -272,6 +274,22 @@ mrsas_write(struct cdev *dev, struct uio *uio, int ioflag)
 	return (0);
 }
 
+u_int32_t
+mrsas_read_reg_with_retries(struct mrsas_softc *sc, int offset)
+{
+	u_int32_t i = 0, ret_val;
+
+	if (sc->is_aero) {
+		do {
+			ret_val = mrsas_read_reg(sc, offset);
+			i++;
+		} while(ret_val == 0 && i < 3);
+	} else
+		ret_val = mrsas_read_reg(sc, offset);
+
+	return ret_val;
+}
+
 /*
  * Register Read/Write Functions
  *
@@ -332,7 +350,7 @@ mrsas_clear_intr(struct mrsas_softc *sc)
 	u_int32_t status;
 
 	/* Read received interrupt */
-	status = mrsas_read_reg(sc, offsetof(mrsas_reg_set, outbound_intr_status));
+	status = mrsas_read_reg_with_retries(sc, offsetof(mrsas_reg_set, outbound_intr_status));
 
 	/* Not our interrupt, so just return */
 	if (!(status & MFI_FUSION_ENABLE_INTERRUPT_MASK))
@@ -2314,7 +2332,7 @@ mrsas_init_fw(struct mrsas_softc *sc)
 		return (ret);
 	}
 	if (sc->is_ventura || sc->is_aero) {
-		scratch_pad_3 = mrsas_read_reg(sc, offsetof(mrsas_reg_set, outbound_scratch_pad_3));
+		scratch_pad_3 = mrsas_read_reg_with_retries(sc, offsetof(mrsas_reg_set, outbound_scratch_pad_3));
 #if VD_EXT_DEBUG
 		device_printf(sc->mrsas_dev, "scratch_pad_3 0x%x\n", scratch_pad_3);
 #endif
@@ -2325,10 +2343,10 @@ mrsas_init_fw(struct mrsas_softc *sc)
 	/* MSI-x index 0- reply post host index register */
 	sc->msix_reg_offset[0] = MPI2_REPLY_POST_HOST_INDEX_OFFSET;
 	/* Check if MSI-X is supported while in ready state */
-	msix_enable = (mrsas_read_reg(sc, offsetof(mrsas_reg_set, outbound_scratch_pad)) & 0x4000000) >> 0x1a;
+	msix_enable = (mrsas_read_reg_with_retries(sc, offsetof(mrsas_reg_set, outbound_scratch_pad)) & 0x4000000) >> 0x1a;
 
 	if (msix_enable) {
-		scratch_pad_2 = mrsas_read_reg(sc, offsetof(mrsas_reg_set,
+		scratch_pad_2 = mrsas_read_reg_with_retries(sc, offsetof(mrsas_reg_set,
 		    outbound_scratch_pad_2));
 
 		/* Check max MSI-X vectors */
@@ -2388,7 +2406,7 @@ mrsas_init_fw(struct mrsas_softc *sc)
 	}
 
 	if (sc->is_ventura || sc->is_aero) {
-		scratch_pad_4 = mrsas_read_reg(sc, offsetof(mrsas_reg_set,
+		scratch_pad_4 = mrsas_read_reg_with_retries(sc, offsetof(mrsas_reg_set,
 		    outbound_scratch_pad_4));
 		if ((scratch_pad_4 & MR_NVME_PAGE_SIZE_MASK) >= MR_DEFAULT_NVME_PAGE_SHIFT)
 			sc->nvme_page_size = 1 << (scratch_pad_4 & MR_NVME_PAGE_SIZE_MASK);
@@ -2529,7 +2547,7 @@ mrsas_init_adapter(struct mrsas_softc *sc)
 	int i = 0;
 
 	/* Read FW status register */
-	status = mrsas_read_reg(sc, offsetof(mrsas_reg_set, outbound_scratch_pad));
+	status = mrsas_read_reg_with_retries(sc, offsetof(mrsas_reg_set, outbound_scratch_pad));
 
 	sc->max_fw_cmds = status & MRSAS_FWSTATE_MAXCMD_MASK;
 
@@ -2544,7 +2562,7 @@ mrsas_init_adapter(struct mrsas_softc *sc)
 	sc->reply_alloc_sz = sizeof(MPI2_REPLY_DESCRIPTORS_UNION) * (sc->reply_q_depth);
 	sc->io_frames_alloc_sz = MRSAS_MPI2_RAID_DEFAULT_IO_FRAME_SIZE +
 	    (MRSAS_MPI2_RAID_DEFAULT_IO_FRAME_SIZE * (sc->max_fw_cmds + 1));
-	scratch_pad_2 = mrsas_read_reg(sc, offsetof(mrsas_reg_set,
+	scratch_pad_2 = mrsas_read_reg_with_retries(sc, offsetof(mrsas_reg_set,
 	    outbound_scratch_pad_2));
 	/*
 	 * If scratch_pad_2 & MEGASAS_MAX_CHAIN_SIZE_UNITS_MASK is set,
@@ -2682,7 +2700,7 @@ mrsas_ioc_init(struct mrsas_softc *sc)
 	}
 
 	if (!sc->block_sync_cache) {
-		scratch_pad_2 = mrsas_read_reg(sc, offsetof(mrsas_reg_set,
+		scratch_pad_2 = mrsas_read_reg_with_retries(sc, offsetof(mrsas_reg_set,
 		    outbound_scratch_pad_2));
 		sc->fw_sync_cache_support = (scratch_pad_2 &
 		    MR_CAN_HANDLE_SYNC_CACHE_OFFSET) ? 1 : 0;
@@ -2758,7 +2776,7 @@ mrsas_ioc_init(struct mrsas_softc *sc)
 	}
 
 	if (sc->is_aero) {
-		scratch_pad_2 = mrsas_read_reg(sc, offsetof(mrsas_reg_set,
+		scratch_pad_2 = mrsas_read_reg_with_retries(sc, offsetof(mrsas_reg_set,
 		    outbound_scratch_pad_2));
 		sc->atomic_desc_support = (scratch_pad_2 &
 			MR_ATOMIC_DESCRIPTOR_SUPPORT_OFFSET) ? 1 : 0;
@@ -2920,7 +2938,7 @@ mrsas_transition_to_ready(struct mrsas_softc *sc, int ocr)
 	u_int32_t cur_state;
 	u_int32_t abs_state, curr_abs_state;
 
-	val = mrsas_read_reg(sc, offsetof(mrsas_reg_set, outbound_scratch_pad));
+	val = mrsas_read_reg_with_retries(sc, offsetof(mrsas_reg_set, outbound_scratch_pad));
 	fw_state = val & MFI_STATE_MASK;
 	max_wait = MRSAS_RESET_WAIT_TIME;
 
@@ -2928,7 +2946,7 @@ mrsas_transition_to_ready(struct mrsas_softc *sc, int ocr)
 		device_printf(sc->mrsas_dev, "Waiting for FW to come to ready state\n");
 
 	while (fw_state != MFI_STATE_READY) {
-		abs_state = mrsas_read_reg(sc, offsetof(mrsas_reg_set, outbound_scratch_pad));
+		abs_state = mrsas_read_reg_with_retries(sc, offsetof(mrsas_reg_set, outbound_scratch_pad));
 		switch (fw_state) {
 		case MFI_STATE_FAULT:
 			device_printf(sc->mrsas_dev, "FW is in FAULT state!!\n");
@@ -2956,7 +2974,7 @@ mrsas_transition_to_ready(struct mrsas_softc *sc, int ocr)
 			mrsas_disable_intr(sc);
 			mrsas_write_reg(sc, offsetof(mrsas_reg_set, doorbell), MFI_RESET_FLAGS);
 			for (i = 0; i < max_wait * 1000; i++) {
-				if (mrsas_read_reg(sc, offsetof(mrsas_reg_set, doorbell)) & 1)
+				if (mrsas_read_reg_with_retries(sc, offsetof(mrsas_reg_set, doorbell)) & 1)
 					DELAY(1000);
 				else
 					break;
@@ -2994,9 +3012,9 @@ mrsas_transition_to_ready(struct mrsas_softc *sc, int ocr)
 		 * The cur_state should not last for more than max_wait secs
 		 */
 		for (i = 0; i < (max_wait * 1000); i++) {
-			fw_state = (mrsas_read_reg(sc, offsetof(mrsas_reg_set,
+			fw_state = (mrsas_read_reg_with_retries(sc, offsetof(mrsas_reg_set,
 			    outbound_scratch_pad)) & MFI_STATE_MASK);
-			curr_abs_state = mrsas_read_reg(sc, offsetof(mrsas_reg_set,
+			curr_abs_state = mrsas_read_reg_with_retries(sc, offsetof(mrsas_reg_set,
 			    outbound_scratch_pad));
 			if (abs_state == curr_abs_state)
 				DELAY(1000);
@@ -3071,7 +3089,7 @@ mrsas_ocr_thread(void *arg)
 			    "Hardware critical error", __func__);
 			break;
 		}
-		fw_status = mrsas_read_reg(sc,
+		fw_status = mrsas_read_reg_with_retries(sc,
 		    offsetof(mrsas_reg_set, outbound_scratch_pad));
 		fw_state = fw_status & MFI_STATE_MASK;
 		if (fw_state == MFI_STATE_FAULT || sc->do_timedout_reset ||
@@ -3230,7 +3248,7 @@ mrsas_reset_ctrl(struct mrsas_softc *sc, u_int8_t reset_reason)
 
 		mtx_lock(&sc->sim_lock);
 
-		status_reg = mrsas_read_reg(sc, offsetof(mrsas_reg_set,
+		status_reg = mrsas_read_reg_with_retries(sc, offsetof(mrsas_reg_set,
 		    outbound_scratch_pad));
 		abs_state = status_reg & MFI_STATE_MASK;
 		reset_adapter = status_reg & MFI_RESET_ADAPTER;
@@ -3260,12 +3278,12 @@ mrsas_reset_ctrl(struct mrsas_softc *sc, u_int8_t reset_reason)
 			    MPI2_WRSEQ_6TH_KEY_VALUE);
 
 			/* Check that the diag write enable (DRWE) bit is on */
-			host_diag = mrsas_read_reg(sc, offsetof(mrsas_reg_set,
+			host_diag = mrsas_read_reg_with_retries(sc, offsetof(mrsas_reg_set,
 			    fusion_host_diag));
 			retry = 0;
 			while (!(host_diag & HOST_DIAG_WRITE_ENABLE)) {
 				DELAY(100 * 1000);
-				host_diag = mrsas_read_reg(sc, offsetof(mrsas_reg_set,
+				host_diag = mrsas_read_reg_with_retries(sc, offsetof(mrsas_reg_set,
 				    fusion_host_diag));
 				if (retry++ == 100) {
 					mrsas_dprint(sc, MRSAS_OCR,
@@ -3282,12 +3300,12 @@ mrsas_reset_ctrl(struct mrsas_softc *sc, u_int8_t reset_reason)
 			DELAY(3000 * 1000);
 
 			/* Make sure reset adapter bit is cleared */
-			host_diag = mrsas_read_reg(sc, offsetof(mrsas_reg_set,
+			host_diag = mrsas_read_reg_with_retries(sc, offsetof(mrsas_reg_set,
 			    fusion_host_diag));
 			retry = 0;
 			while (host_diag & HOST_DIAG_RESET_ADAPTER) {
 				DELAY(100 * 1000);
-				host_diag = mrsas_read_reg(sc, offsetof(mrsas_reg_set,
+				host_diag = mrsas_read_reg_with_retries(sc, offsetof(mrsas_reg_set,
 				    fusion_host_diag));
 				if (retry++ == 1000) {
 					mrsas_dprint(sc, MRSAS_OCR,
@@ -3298,13 +3316,13 @@ mrsas_reset_ctrl(struct mrsas_softc *sc, u_int8_t reset_reason)
 			if (host_diag & HOST_DIAG_RESET_ADAPTER)
 				continue;
 
-			abs_state = mrsas_read_reg(sc, offsetof(mrsas_reg_set,
+			abs_state = mrsas_read_reg_with_retries(sc, offsetof(mrsas_reg_set,
 			    outbound_scratch_pad)) & MFI_STATE_MASK;
 			retry = 0;
 
 			while ((abs_state <= MFI_STATE_FW_INIT) && (retry++ < 1000)) {
 				DELAY(100 * 1000);
-				abs_state = mrsas_read_reg(sc, offsetof(mrsas_reg_set,
+				abs_state = mrsas_read_reg_with_retries(sc, offsetof(mrsas_reg_set,
 				    outbound_scratch_pad)) & MFI_STATE_MASK;
 			}
 			if (abs_state <= MFI_STATE_FW_INIT) {
@@ -3479,7 +3497,7 @@ mrsas_wait_for_outstanding(struct mrsas_softc *sc, u_int8_t check_reason)
 			goto out;
 		}
 		/* Check if firmware is in fault state */
-		fw_state = mrsas_read_reg(sc, offsetof(mrsas_reg_set,
+		fw_state = mrsas_read_reg_with_retries(sc, offsetof(mrsas_reg_set,
 		    outbound_scratch_pad)) & MFI_STATE_MASK;
 		if (fw_state == MFI_STATE_FAULT) {
 			mrsas_dprint(sc, MRSAS_OCR,