[PATCH V2 0/2] Separate out earlycon

[PATCH V2 0/2] Separate out earlycon

[Roja Rani Yarubandi]

Dropped below patch as it is not required:
[3/3] Serial: Separate out earlycon support

Roja Rani Yarubandi (2):
  soc: qcom-geni-se: Cleanup the code to remove proxy votes
  arm64: dts: qcom: sc7180: Remove QUP-CORE ICC path

 arch/arm64/boot/dts/qcom/sc7180.dtsi  |  4 --
 drivers/soc/qcom/qcom-geni-se.c       | 74 ---------------------------
 drivers/tty/serial/qcom_geni_serial.c |  7 ---
 include/linux/qcom-geni-se.h          |  2 -
 4 files changed, 87 deletions(-)

-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member 
of Code Aurora Forum, hosted by The Linux Foundation

[PATCH V2 1/2] soc: qcom-geni-se: Cleanup the code to remove proxy votes

[Roja Rani Yarubandi]

ICC core and platforms drivers supports sync_state feature, which
ensures that the default ICC BW votes from the bootloader is not
removed until all it's consumers are probes.

The proxy votes were needed in case other QUP child drivers
I2C, SPI probes before UART, they can turn off the QUP-CORE clock
which is shared resources for all QUP driver, this causes unclocked
access to HW from earlycon.

Given above support from ICC there is no longer need to maintain
proxy votes on QUP-CORE ICC node from QUP wrapper driver for early
console usecase, the default votes won't be removed until real
console is probed.

Signed-off-by: Roja Rani Yarubandi <rojay@codeaurora.org>
Signed-off-by: Akash Asthana <akashast@codeaurora.org>
---
Changes in V2:
 - No chage

 drivers/soc/qcom/qcom-geni-se.c       | 74 ---------------------------
 drivers/tty/serial/qcom_geni_serial.c |  7 ---
 include/linux/qcom-geni-se.h          |  2 -
 3 files changed, 83 deletions(-)

diff --git a/drivers/soc/qcom/qcom-geni-se.c b/drivers/soc/qcom/qcom-geni-se.c
index c7c03ccfe888..5bdfb1565c14 100644
--- a/drivers/soc/qcom/qcom-geni-se.c
+++ b/drivers/soc/qcom/qcom-geni-se.c
@@ -3,7 +3,6 @@
 
 #include <linux/acpi.h>
 #include <linux/clk.h>
-#include <linux/console.h>
 #include <linux/slab.h>
 #include <linux/dma-mapping.h>
 #include <linux/io.h>
@@ -92,14 +91,11 @@ struct geni_wrapper {
 	struct device *dev;
 	void __iomem *base;
 	struct clk_bulk_data ahb_clks[NUM_AHB_CLKS];
-	struct geni_icc_path to_core;
 };
 
 static const char * const icc_path_names[] = {"qup-core", "qup-config",
 						"qup-memory"};
 
-static struct geni_wrapper *earlycon_wrapper;
-
 #define QUP_HW_VER_REG			0x4
 
 /* Common SE registers */
@@ -846,44 +842,11 @@ int geni_icc_disable(struct geni_se *se)
 }
 EXPORT_SYMBOL(geni_icc_disable);
 
-void geni_remove_earlycon_icc_vote(void)
-{
-	struct platform_device *pdev;
-	struct geni_wrapper *wrapper;
-	struct device_node *parent;
-	struct device_node *child;
-
-	if (!earlycon_wrapper)
-		return;
-
-	wrapper = earlycon_wrapper;
-	parent = of_get_next_parent(wrapper->dev->of_node);
-	for_each_child_of_node(parent, child) {
-		if (!of_device_is_compatible(child, "qcom,geni-se-qup"))
-			continue;
-
-		pdev = of_find_device_by_node(child);
-		if (!pdev)
-			continue;
-
-		wrapper = platform_get_drvdata(pdev);
-		icc_put(wrapper->to_core.path);
-		wrapper->to_core.path = NULL;
-
-	}
-	of_node_put(parent);
-
-	earlycon_wrapper = NULL;
-}
-EXPORT_SYMBOL(geni_remove_earlycon_icc_vote);
-
 static int geni_se_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct resource *res;
 	struct geni_wrapper *wrapper;
-	struct console __maybe_unused *bcon;
-	bool __maybe_unused has_earlycon = false;
 	int ret;
 
 	wrapper = devm_kzalloc(dev, sizeof(*wrapper), GFP_KERNEL);
@@ -906,43 +869,6 @@ static int geni_se_probe(struct platform_device *pdev)
 		}
 	}
 
-#ifdef CONFIG_SERIAL_EARLYCON
-	for_each_console(bcon) {
-		if (!strcmp(bcon->name, "qcom_geni")) {
-			has_earlycon = true;
-			break;
-		}
-	}
-	if (!has_earlycon)
-		goto exit;
-
-	wrapper->to_core.path = devm_of_icc_get(dev, "qup-core");
-	if (IS_ERR(wrapper->to_core.path))
-		return PTR_ERR(wrapper->to_core.path);
-	/*
-	 * Put minmal BW request on core clocks on behalf of early console.
-	 * The vote will be removed earlycon exit function.
-	 *
-	 * Note: We are putting vote on each QUP wrapper instead only to which
-	 * earlycon is connected because QUP core clock of different wrapper
-	 * share same voltage domain. If core1 is put to 0, then core2 will
-	 * also run at 0, if not voted. Default ICC vote will be removed ASA
-	 * we touch any of the core clock.
-	 * core1 = core2 = max(core1, core2)
-	 */
-	ret = icc_set_bw(wrapper->to_core.path, GENI_DEFAULT_BW,
-				GENI_DEFAULT_BW);
-	if (ret) {
-		dev_err(&pdev->dev, "%s: ICC BW voting failed for core: %d\n",
-			__func__, ret);
-		return ret;
-	}
-
-	if (of_get_compatible_child(pdev->dev.of_node, "qcom,geni-debug-uart"))
-		earlycon_wrapper = wrapper;
-	of_node_put(pdev->dev.of_node);
-exit:
-#endif
 	dev_set_drvdata(dev, wrapper);
 	dev_dbg(dev, "GENI SE Driver probed\n");
 	return devm_of_platform_populate(dev);
diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index 3872bbfac24b..99375d99f6fa 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -1177,12 +1177,6 @@ static inline void qcom_geni_serial_enable_early_read(struct geni_se *se,
 						      struct console *con) { }
 #endif
 
-static int qcom_geni_serial_earlycon_exit(struct console *con)
-{
-	geni_remove_earlycon_icc_vote();
-	return 0;
-}
-
 static struct qcom_geni_private_data earlycon_private_data;
 
 static int __init qcom_geni_serial_earlycon_setup(struct earlycon_device *dev,
@@ -1233,7 +1227,6 @@ static int __init qcom_geni_serial_earlycon_setup(struct earlycon_device *dev,
 	writel(stop_bit_len, uport->membase + SE_UART_TX_STOP_BIT_LEN);
 
 	dev->con->write = qcom_geni_serial_earlycon_write;
-	dev->con->exit = qcom_geni_serial_earlycon_exit;
 	dev->con->setup = NULL;
 	qcom_geni_serial_enable_early_read(&se, dev->con);
 
diff --git a/include/linux/qcom-geni-se.h b/include/linux/qcom-geni-se.h
index cddef864a760..7c811eebcaab 100644
--- a/include/linux/qcom-geni-se.h
+++ b/include/linux/qcom-geni-se.h
@@ -458,7 +458,5 @@ void geni_icc_set_tag(struct geni_se *se, u32 tag);
 int geni_icc_enable(struct geni_se *se);
 
 int geni_icc_disable(struct geni_se *se);
-
-void geni_remove_earlycon_icc_vote(void);
 #endif
 #endif
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member 
of Code Aurora Forum, hosted by The Linux Foundation

[PATCH V2 2/2] arm64: dts: qcom: sc7180: Remove QUP-CORE ICC path

[Roja Rani Yarubandi]

We had introduced the QUP-CORE ICC path to put proxy votes from
QUP wrapper on behalf of earlycon, if other users of QUP-CORE turn
off this clock before the real console is probed, unclocked access
to HW was seen from earlycon.

With ICC sync state support proxy votes are no longer need as ICC
will ensure that the default bootloader votes are not removed until
all it's consumer are probed.

We can safely remove ICC path for QUP-CORE clock from QUP wrapper
device.

Signed-off-by: Roja Rani Yarubandi <rojay@codeaurora.org>
Signed-off-by: Akash Asthana <akashast@codeaurora.org>
---
Changes in V2:
 - No chage

 arch/arm64/boot/dts/qcom/sc7180.dtsi | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/arch/arm64/boot/dts/qcom/sc7180.dtsi b/arch/arm64/boot/dts/qcom/sc7180.dtsi
index 83fbb481cae5..2709051740d1 100644
--- a/arch/arm64/boot/dts/qcom/sc7180.dtsi
+++ b/arch/arm64/boot/dts/qcom/sc7180.dtsi
@@ -768,8 +768,6 @@ qupv3_id_0: geniqup@8c0000 {
 			#size-cells = <2>;
 			ranges;
 			iommus = <&apps_smmu 0x43 0x0>;
-			interconnects = <&qup_virt MASTER_QUP_CORE_0 0 &qup_virt SLAVE_QUP_CORE_0 0>;
-			interconnect-names = "qup-core";
 			status = "disabled";
 
 			i2c0: i2c@880000 {
@@ -1059,8 +1057,6 @@ qupv3_id_1: geniqup@ac0000 {
 			#size-cells = <2>;
 			ranges;
 			iommus = <&apps_smmu 0x4c3 0x0>;
-			interconnects = <&qup_virt MASTER_QUP_CORE_1 0 &qup_virt SLAVE_QUP_CORE_1 0>;
-			interconnect-names = "qup-core";
 			status = "disabled";
 
 			i2c6: i2c@a80000 {
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member 
of Code Aurora Forum, hosted by The Linux Foundation

Re: [PATCH V2 1/2] soc: qcom-geni-se: Cleanup the code to remove proxy votes

[Matthias Kaehlcke]

On Thu, Mar 18, 2021 at 04:40:08PM +0530, Roja Rani Yarubandi wrote:
> ICC core and platforms drivers supports sync_state feature, which
> ensures that the default ICC BW votes from the bootloader is not
> removed until all it's consumers are probes.
> 
> The proxy votes were needed in case other QUP child drivers
> I2C, SPI probes before UART, they can turn off the QUP-CORE clock
> which is shared resources for all QUP driver, this causes unclocked
> access to HW from earlycon.
> 
> Given above support from ICC there is no longer need to maintain
> proxy votes on QUP-CORE ICC node from QUP wrapper driver for early
> console usecase, the default votes won't be removed until real
> console is probed.
> 
> Signed-off-by: Roja Rani Yarubandi <rojay@codeaurora.org>
> Signed-off-by: Akash Asthana <akashast@codeaurora.org>

I suggest to mention that this is essentially a revert of commit
048eb908a1f2 ("soc: qcom-geni-se: Add interconnect support to fix
earlycon crash"). This makes the life of reviewers easier and it's
also good to have the reference in the git history.

You could also mention commit 7d3b0b0d8184 ("interconnect: qcom:
Use icc_sync_state") in the intro.

I tried to test by first reproducing the original issue without
'sync_state' in the ICC, but wasn't successful, probably something
changed in the boot/ICC timing in the meantime ¯\_(ツ)_/¯.

Reviewed-by: Matthias Kaehlcke <mka@chromium.org>

Re: [PATCH V2 2/2] arm64: dts: qcom: sc7180: Remove QUP-CORE ICC path

[Matthias Kaehlcke]

On Thu, Mar 18, 2021 at 04:40:09PM +0530, Roja Rani Yarubandi wrote:
> We had introduced the QUP-CORE ICC path to put proxy votes from
> QUP wrapper on behalf of earlycon, if other users of QUP-CORE turn
> off this clock before the real console is probed, unclocked access
> to HW was seen from earlycon.
> 
> With ICC sync state support proxy votes are no longer need as ICC
> will ensure that the default bootloader votes are not removed until
> all it's consumer are probed.
> 
> We can safely remove ICC path for QUP-CORE clock from QUP wrapper
> device.
> 
> Signed-off-by: Roja Rani Yarubandi <rojay@codeaurora.org>
> Signed-off-by: Akash Asthana <akashast@codeaurora.org>

Reviewed-by: Matthias Kaehlcke <mka@chromium.org>

Re: [PATCH V2 1/2] soc: qcom-geni-se: Cleanup the code to remove proxy votes

[rojay]

On 2021-03-18 22:43, Matthias Kaehlcke wrote:
> On Thu, Mar 18, 2021 at 04:40:08PM +0530, Roja Rani Yarubandi wrote:
>> ICC core and platforms drivers supports sync_state feature, which
>> ensures that the default ICC BW votes from the bootloader is not
>> removed until all it's consumers are probes.
>> 
>> The proxy votes were needed in case other QUP child drivers
>> I2C, SPI probes before UART, they can turn off the QUP-CORE clock
>> which is shared resources for all QUP driver, this causes unclocked
>> access to HW from earlycon.
>> 
>> Given above support from ICC there is no longer need to maintain
>> proxy votes on QUP-CORE ICC node from QUP wrapper driver for early
>> console usecase, the default votes won't be removed until real
>> console is probed.
>> 
>> Signed-off-by: Roja Rani Yarubandi <rojay@codeaurora.org>
>> Signed-off-by: Akash Asthana <akashast@codeaurora.org>
> 
> I suggest to mention that this is essentially a revert of commit
> 048eb908a1f2 ("soc: qcom-geni-se: Add interconnect support to fix
> earlycon crash"). This makes the life of reviewers easier and it's
> also good to have the reference in the git history.
> 

Ok.

> You could also mention commit 7d3b0b0d8184 ("interconnect: qcom:
> Use icc_sync_state") in the intro.
> 

Ok.

> I tried to test by first reproducing the original issue without
> 'sync_state' in the ICC, but wasn't successful, probably something
> changed in the boot/ICC timing in the meantime ¯\_(ツ)_/¯.
> 

Need to remove runtime auto suspend support from SPI/I2C as well, as it 
was
masking the issue by delaying to turn off the resources by 250ms.

> Reviewed-by: Matthias Kaehlcke <mka@chromium.org>