[PATCH 0/2] soc: qcom: geni-se: Avoid redundant transfer mode selection

[PATCH 0/2] soc: qcom: geni-se: Avoid redundant transfer mode selection

[Viken Dadhaniya]

The GENI transfer mode is commonly unchanged across consecutive transfers,
but geni_se_select_mode() currently reprograms mode-related registers on
every call.

Avoid redundant mode programming by caching the previously selected mode.
Pending GENI and DMA interrupt status is still cleared for cached selections
so stale completion status cannot complete a subsequent transfer after a
timeout, abort, or reset. GSI event routing remains enabled for cached GPI
mode selections.

This series:

  1. Separates IRQ status clearing from the full mode-reset operation.
  2. Adds transfer-mode caching to avoid redundant mode programming.

Signed-off-by: Viken Dadhaniya <viken.dadhaniya@oss.qualcomm.com>
---
Viken Dadhaniya (2):
      soc: qcom: geni-se: Split IRQ status clearing from mode selection
      soc: qcom: geni-se: Avoid redundant transfer mode selection

 drivers/soc/qcom/qcom-geni-se.c  | 20 +++++++++++++++++---
 include/linux/soc/qcom/geni-se.h |  1 +
 2 files changed, 18 insertions(+), 3 deletions(-)
---
base-commit: becb95e45ef0dda9ffb35156d909d3da7a2789c3
change-id: 20261012-cache-se-mode-578c2fa35af1

Best regards,
--  
Viken Dadhaniya <viken.dadhaniya@oss.qualcomm.com>

[PATCH 1/2] soc: qcom: geni-se: Split IRQ status clearing from mode selection

[Viken Dadhaniya]

geni_se_irq_clear() both clears pending interrupt status and updates
mode-dependent event and IRQ enables. Split out the status-only operation
so cached mode selections can discard stale transfer completion status
without disabling GSI event routing.

No functional change.

Signed-off-by: Viken Dadhaniya <viken.dadhaniya@oss.qualcomm.com>
---
 drivers/soc/qcom/qcom-geni-se.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/soc/qcom/qcom-geni-se.c b/drivers/soc/qcom/qcom-geni-se.c
index 074087c592cc..311046544b4c 100644
--- a/drivers/soc/qcom/qcom-geni-se.c
+++ b/drivers/soc/qcom/qcom-geni-se.c
@@ -342,13 +342,18 @@ static void geni_se_io_init(void __iomem *base)
 	writel_relaxed(FORCE_DEFAULT, base + GENI_FORCE_DEFAULT_REG);
 }
 
-static void geni_se_irq_clear(struct geni_se *se)
+static void geni_se_clear_irq_status(struct geni_se *se)
 {
-	writel_relaxed(0, se->base + SE_GSI_EVENT_EN);
 	writel_relaxed(0xffffffff, se->base + SE_GENI_M_IRQ_CLEAR);
 	writel_relaxed(0xffffffff, se->base + SE_GENI_S_IRQ_CLEAR);
 	writel_relaxed(0xffffffff, se->base + SE_DMA_TX_IRQ_CLR);
 	writel_relaxed(0xffffffff, se->base + SE_DMA_RX_IRQ_CLR);
+}
+
+static void geni_se_irq_clear(struct geni_se *se)
+{
+	writel_relaxed(0, se->base + SE_GSI_EVENT_EN);
+	geni_se_clear_irq_status(se);
 	writel_relaxed(0xffffffff, se->base + SE_IRQ_EN);
 }
 

-- 
2.34.1

[PATCH 2/2] soc: qcom: geni-se: Avoid redundant transfer mode selection

[Viken Dadhaniya]

geni_se_select_mode() is called for every FIFO and SE-DMA transfer, even
when the serial engine is already configured for the requested mode. Each
call clears interrupt status and accesses mode-related registers, causing
unnecessary MMIO operations on the transfer path.

Cache the previously selected mode and skip only redundant mode
programming. Preserve pending interrupt status cleanup and GPI event
routing. Invalidate the cache from geni_se_init(). Update it only after a
valid mode selection.

Signed-off-by: Viken Dadhaniya <viken.dadhaniya@oss.qualcomm.com>
---
 drivers/soc/qcom/qcom-geni-se.c  | 11 ++++++++++-
 include/linux/soc/qcom/geni-se.h |  1 +
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/soc/qcom/qcom-geni-se.c b/drivers/soc/qcom/qcom-geni-se.c
index 311046544b4c..ce4de4917a83 100644
--- a/drivers/soc/qcom/qcom-geni-se.c
+++ b/drivers/soc/qcom/qcom-geni-se.c
@@ -370,6 +370,8 @@ void geni_se_init(struct geni_se *se, u32 rx_wm, u32 rx_rfr)
 {
 	u32 val;
 
+	se->prev_xfer_mode = GENI_SE_INVALID;
+
 	geni_se_irq_clear(se);
 	geni_se_io_init(se->base);
 	geni_se_io_set_mode(se->base);
@@ -462,6 +464,11 @@ void geni_se_select_mode(struct geni_se *se, enum geni_se_xfer_mode mode)
 {
 	WARN_ON(mode != GENI_SE_FIFO && mode != GENI_SE_DMA && mode != GENI_GPI_DMA);
 
+	if (likely(se->prev_xfer_mode == mode)) {
+		geni_se_clear_irq_status(se);
+		return;
+	}
+
 	switch (mode) {
 	case GENI_SE_FIFO:
 		geni_se_select_fifo_mode(se);
@@ -474,8 +481,10 @@ void geni_se_select_mode(struct geni_se *se, enum geni_se_xfer_mode mode)
 		break;
 	case GENI_SE_INVALID:
 	default:
-		break;
+		return;
 	}
+
+	se->prev_xfer_mode = mode;
 }
 EXPORT_SYMBOL_GPL(geni_se_select_mode);
 
diff --git a/include/linux/soc/qcom/geni-se.h b/include/linux/soc/qcom/geni-se.h
index b3372a3147a0..f77c3a47c3d0 100644
--- a/include/linux/soc/qcom/geni-se.h
+++ b/include/linux/soc/qcom/geni-se.h
@@ -78,6 +78,7 @@ struct geni_se {
 	struct geni_icc_path icc_paths[3];
 	struct dev_pm_domain_list *pd_list;
 	bool has_opp;
+	enum geni_se_xfer_mode prev_xfer_mode;
 };
 
 /* Common SE registers */

-- 
2.34.1