From 600c39b34369e2a1bf78eb67afb99ce550f271cc Mon Sep 17 00:00:00 2001 From: Sibi Sankar Date: Thu, 23 Jan 2020 18:42:36 +0530 Subject: remoteproc: qcom: q6v5-mss: Improve readability of reset_assert Define AXI_GATING_VALID_OVERRIDE and fixup comments to improve readability of Q6 modem reset sequence on SC7180 SoCs. Reviewed-by: Evan Green Signed-off-by: Sibi Sankar Link: https://lore.kernel.org/r/20200123131236.1078-3-sibis@codeaurora.org Signed-off-by: Bjorn Andersson --- drivers/remoteproc/qcom_q6v5_mss.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) (limited to 'drivers/remoteproc') diff --git a/drivers/remoteproc/qcom_q6v5_mss.c b/drivers/remoteproc/qcom_q6v5_mss.c index 89ab96c21a44..a1cc9cbe038f 100644 --- a/drivers/remoteproc/qcom_q6v5_mss.c +++ b/drivers/remoteproc/qcom_q6v5_mss.c @@ -71,6 +71,7 @@ #define NAV_AXI_HALTREQ_BIT BIT(0) #define NAV_AXI_HALTACK_BIT BIT(1) #define NAV_AXI_IDLE_BIT BIT(2) +#define AXI_GATING_VALID_OVERRIDE BIT(0) #define HALT_ACK_TIMEOUT_US 100000 #define NAV_HALT_ACK_TIMEOUT_US 200 @@ -415,16 +416,24 @@ static int q6v5_reset_assert(struct q6v5 *qproc) ret = reset_control_reset(qproc->mss_restart); reset_control_deassert(qproc->pdc_reset); } else if (qproc->has_halt_nav) { - /* SWAR using CONN_BOX_SPARE_0 for pipeline glitch issue */ + /* + * When the AXI pipeline is being reset with the Q6 modem partly + * operational there is possibility of AXI valid signal to + * glitch, leading to spurious transactions and Q6 hangs. A work + * around is employed by asserting the AXI_GATING_VALID_OVERRIDE + * BIT before triggering Q6 MSS reset. Both the HALTREQ and + * AXI_GATING_VALID_OVERRIDE are withdrawn post MSS assert + * followed by a MSS deassert, while holding the PDC reset. + */ reset_control_assert(qproc->pdc_reset); regmap_update_bits(qproc->conn_map, qproc->conn_box, - BIT(0), BIT(0)); + AXI_GATING_VALID_OVERRIDE, 1); regmap_update_bits(qproc->halt_nav_map, qproc->halt_nav, NAV_AXI_HALTREQ_BIT, 0); reset_control_assert(qproc->mss_restart); reset_control_deassert(qproc->pdc_reset); regmap_update_bits(qproc->conn_map, qproc->conn_box, - BIT(0), 0); + AXI_GATING_VALID_OVERRIDE, 0); ret = reset_control_deassert(qproc->mss_restart); } else { ret = reset_control_assert(qproc->mss_restart); -- cgit v1.2.3-59-g8ed1b