[PATCH v3 0/3] Even moar rpmh cleanups

[PATCH v3 0/3] Even moar rpmh cleanups

[Stephen Boyd]

We remove the tcs_is_free() API and then do super micro optimizations on
the irq handler. I haven't tested anything here so most likely there's a
bug (again again)!

Changes from v2:
 * Went back in time and used the v1 patch for the first patch with
   the fixes to make it not so complicated

Changes from v1:
 * First patch became even moar complicated because it combines
   find_free_tcs() with the check for a request in flight
 * Fixed subject in patch 2
 * Put back unsigned long for bitmap operation to silence compiler
   warning
 * Picked up review tags

Stephen Boyd (3):
  soc: qcom: rpmh-rsc: Remove tcs_is_free() API
  soc: qcom: rpmh-rsc: Loop over fewer bits in irq handler
  soc: qcom: rpmh-rsc: Fold WARN_ON() into if condition

 drivers/soc/qcom/rpmh-rsc.c | 65 +++++++++++++------------------------
 1 file changed, 22 insertions(+), 43 deletions(-)

Cc: Maulik Shah <mkshah@codeaurora.org>
Cc: Douglas Anderson <dianders@chromium.org>

base-commit: 1f7a3eb785e4a4e196729cd3d5ec97bd5f9f2940
-- 
Sent by a computer, using git, on the internet

[PATCH v3 1/3] soc: qcom: rpmh-rsc: Remove tcs_is_free() API

[Stephen Boyd]

This API does very little. Let's replace all the callsites with the
normal operations that would be done on top of the bitmap that
tcs_in_use is. This simplifies and reduces the code size.

Cc: Maulik Shah <mkshah@codeaurora.org>
Cc: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
---
 drivers/soc/qcom/rpmh-rsc.c | 59 +++++++++++++------------------------
 1 file changed, 20 insertions(+), 39 deletions(-)

diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
index 076fd27f3081..60fc56987659 100644
--- a/drivers/soc/qcom/rpmh-rsc.c
+++ b/drivers/soc/qcom/rpmh-rsc.c
@@ -184,22 +184,6 @@ static void write_tcs_reg_sync(const struct rsc_drv *drv, int reg, int tcs_id,
 		       data, tcs_id, reg);
 }
 
-/**
- * tcs_is_free() - Return if a TCS is totally free.
- * @drv:    The RSC controller.
- * @tcs_id: The global ID of this TCS.
- *
- * Returns true if nobody has claimed this TCS (by setting tcs_in_use).
- *
- * Context: Must be called with the drv->lock held.
- *
- * Return: true if the given TCS is free.
- */
-static bool tcs_is_free(struct rsc_drv *drv, int tcs_id)
-{
-	return !test_bit(tcs_id, drv->tcs_in_use);
-}
-
 /**
  * tcs_invalidate() - Invalidate all TCSes of the given type (sleep or wake).
  * @drv:  The RSC controller.
@@ -512,7 +496,7 @@ static void __tcs_buffer_write(struct rsc_drv *drv, int tcs_id, int cmd_id,
  *
  * Return: 0 if nothing in flight or -EBUSY if we should try again later.
  *         The caller must re-enable interrupts between tries since that's
- *         the only way tcs_is_free() will ever return true and the only way
+ *         the only way tcs_in_use will ever be updated and the only way
  *         RSC_DRV_CMD_ENABLE will ever be cleared.
  */
 static int check_for_req_inflight(struct rsc_drv *drv, struct tcs_group *tcs,
@@ -520,17 +504,14 @@ static int check_for_req_inflight(struct rsc_drv *drv, struct tcs_group *tcs,
 {
 	unsigned long curr_enabled;
 	u32 addr;
-	int i, j, k;
-	int tcs_id = tcs->offset;
+	int j, k;
+	int i = tcs->offset;
 
-	for (i = 0; i < tcs->num_tcs; i++, tcs_id++) {
-		if (tcs_is_free(drv, tcs_id))
-			continue;
-
-		curr_enabled = read_tcs_reg(drv, RSC_DRV_CMD_ENABLE, tcs_id);
+	for_each_set_bit_from(i, drv->tcs_in_use, tcs->offset + tcs->num_tcs) {
+		curr_enabled = read_tcs_reg(drv, RSC_DRV_CMD_ENABLE, i);
 
 		for_each_set_bit(j, &curr_enabled, MAX_CMDS_PER_TCS) {
-			addr = read_tcs_cmd(drv, RSC_DRV_CMD_ADDR, tcs_id, j);
+			addr = read_tcs_cmd(drv, RSC_DRV_CMD_ADDR, i, j);
 			for (k = 0; k < msg->num_cmds; k++) {
 				if (addr == msg->cmds[k].addr)
 					return -EBUSY;
@@ -548,18 +529,19 @@ static int check_for_req_inflight(struct rsc_drv *drv, struct tcs_group *tcs,
  *
  * Must be called with the drv->lock held since that protects tcs_in_use.
  *
- * Return: The first tcs that's free.
+ * Return: The first tcs that's free or -EBUSY if all in use.
  */
 static int find_free_tcs(struct tcs_group *tcs)
 {
-	int i;
+	const struct rsc_drv *drv = tcs->drv;
+	unsigned long i;
+	unsigned long max = tcs->offset + tcs->num_tcs;
 
-	for (i = 0; i < tcs->num_tcs; i++) {
-		if (tcs_is_free(tcs->drv, tcs->offset + i))
-			return tcs->offset + i;
-	}
+	i = find_next_zero_bit(drv->tcs_in_use, max, tcs->offset);
+	if (i >= max)
+		return -EBUSY;
 
-	return -EBUSY;
+	return i;
 }
 
 /**
@@ -757,8 +739,9 @@ int rpmh_rsc_write_ctrl_data(struct rsc_drv *drv, const struct tcs_request *msg)
  */
 static bool rpmh_rsc_ctrlr_is_busy(struct rsc_drv *drv)
 {
-	int m;
-	struct tcs_group *tcs = &drv->tcs[ACTIVE_TCS];
+	unsigned long set;
+	const struct tcs_group *tcs = &drv->tcs[ACTIVE_TCS];
+	unsigned long max;
 
 	/*
 	 * If we made an active request on a RSC that does not have a
@@ -769,12 +752,10 @@ static bool rpmh_rsc_ctrlr_is_busy(struct rsc_drv *drv)
 	if (!tcs->num_tcs)
 		tcs = &drv->tcs[WAKE_TCS];
 
-	for (m = tcs->offset; m < tcs->offset + tcs->num_tcs; m++) {
-		if (!tcs_is_free(drv, m))
-			return true;
-	}
+	max = tcs->offset + tcs->num_tcs;
+	set = find_next_bit(drv->tcs_in_use, max, tcs->offset);
 
-	return false;
+	return set < max;
 }
 
 /**
-- 
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[PATCH v3 2/3] soc: qcom: rpmh-rsc: Loop over fewer bits in irq handler

[Stephen Boyd]

readl() returns a u32, and BITS_PER_LONG is different on 32-bit vs.
64-bit architectures. Let's loop over the possible bits set in that type
instead of looping over more bits than we ever may need to.

Cc: Maulik Shah <mkshah@codeaurora.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
---
 drivers/soc/qcom/rpmh-rsc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
index 60fc56987659..ce725d4ff097 100644
--- a/drivers/soc/qcom/rpmh-rsc.c
+++ b/drivers/soc/qcom/rpmh-rsc.c
@@ -383,7 +383,7 @@ static irqreturn_t tcs_tx_done(int irq, void *p)
 
 	irq_status = readl_relaxed(drv->tcs_base + RSC_DRV_IRQ_STATUS);
 
-	for_each_set_bit(i, &irq_status, BITS_PER_LONG) {
+	for_each_set_bit(i, &irq_status, BITS_PER_TYPE(u32)) {
 		req = get_req_from_tcs(drv, i);
 		if (!req) {
 			WARN_ON(1);
-- 
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[PATCH v3 3/3] soc: qcom: rpmh-rsc: Fold WARN_ON() into if condition

[Stephen Boyd]

Move the WARN_ON() into the if condition so the compiler can see that
the branch is unlikely() and possibly optimize it better.

Cc: Maulik Shah <mkshah@codeaurora.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
---
 drivers/soc/qcom/rpmh-rsc.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
index ce725d4ff097..8381bd012de4 100644
--- a/drivers/soc/qcom/rpmh-rsc.c
+++ b/drivers/soc/qcom/rpmh-rsc.c
@@ -385,10 +385,8 @@ static irqreturn_t tcs_tx_done(int irq, void *p)
 
 	for_each_set_bit(i, &irq_status, BITS_PER_TYPE(u32)) {
 		req = get_req_from_tcs(drv, i);
-		if (!req) {
-			WARN_ON(1);
+		if (WARN_ON(!req))
 			goto skip;
-		}
 
 		err = 0;
 		for (j = 0; j < req->num_cmds; j++) {
-- 
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Re: [PATCH v3 0/3] Even moar rpmh cleanups

[Bjorn Andersson]

On Wed 20 May 18:21 PDT 2020, Stephen Boyd wrote:

> We remove the tcs_is_free() API and then do super micro optimizations on
> the irq handler. I haven't tested anything here so most likely there's a
> bug (again again)!
> 
> Changes from v2:
>  * Went back in time and used the v1 patch for the first patch with
>    the fixes to make it not so complicated
> 
> Changes from v1:
>  * First patch became even moar complicated because it combines
>    find_free_tcs() with the check for a request in flight
>  * Fixed subject in patch 2
>  * Put back unsigned long for bitmap operation to silence compiler
>    warning
>  * Picked up review tags
> 

Can you please resend this series with both linux-arm-msm and myself on
Cc for all three patches?

Thanks,
Bjorn

> Stephen Boyd (3):
>   soc: qcom: rpmh-rsc: Remove tcs_is_free() API
>   soc: qcom: rpmh-rsc: Loop over fewer bits in irq handler
>   soc: qcom: rpmh-rsc: Fold WARN_ON() into if condition
> 
>  drivers/soc/qcom/rpmh-rsc.c | 65 +++++++++++++------------------------
>  1 file changed, 22 insertions(+), 43 deletions(-)
> 
> Cc: Maulik Shah <mkshah@codeaurora.org>
> Cc: Douglas Anderson <dianders@chromium.org>
> 
> base-commit: 1f7a3eb785e4a4e196729cd3d5ec97bd5f9f2940
> -- 
> Sent by a computer, using git, on the internet
>