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* [PATCH v2] regulator: ti-abb: don't use devm_platform_ioremap_resource_byname for shared interrupt register
@ 2024-01-23 11:14 Romain Naour
  2024-01-24 18:11 ` Mark Brown
  0 siblings, 1 reply; 2+ messages in thread
From: Romain Naour @ 2024-01-23 11:14 UTC (permalink / raw)
  To: linux-kernel, linux-omap
  Cc: tony, lgirdwood, broonie, Romain Naour, Yoann Congal

From: Romain Naour <romain.naour@skf.com>

We can't use devm_platform_ioremap_resource_byname() to remap the
interrupt register that can be shared between
regulator-abb-{ivahd,dspeve,gpu} drivers instances.

The combined helper introduce a call to devm_request_mem_region() that
creates a new busy resource region on PRM_IRQSTATUS_MPU register
(0x4ae06010). The first devm_request_mem_region() call succeeds for
regulator-abb-ivahd but fails for the two other regulator-abb-dspeve
and regulator-abb-gpu.

  # cat /proc/iomem | grep -i 4ae06
  4ae06010-4ae06013 : 4ae07e34.regulator-abb-ivahd int-address
  4ae06014-4ae06017 : 4ae07ddc.regulator-abb-mpu int-address

regulator-abb-dspeve and regulator-abb-gpu are missing due to
devm_request_mem_region() failure (EBUSY):

  [    1.326660] ti_abb 4ae07e30.regulator-abb-dspeve: can't request region for resource [mem 0x4ae06010-0x4ae06013]
  [    1.326660] ti_abb: probe of 4ae07e30.regulator-abb-dspeve failed with error -16
  [    1.327239] ti_abb 4ae07de4.regulator-abb-gpu: can't request region for resource [mem 0x4ae06010-0x4ae06013]
  [    1.327270] ti_abb: probe of 4ae07de4.regulator-abb-gpu failed with error -16

From arm/boot/dts/dra7.dtsi:

The abb_mpu is the only instance using its own interrupt register:
  (0x4ae06014) PRM_IRQSTATUS_MPU_2, ABB_MPU_DONE_ST (bit 7)

The other tree instances (abb_ivahd, abb_dspeve, abb_gpu) share
PRM_IRQSTATUS_MPU register (0x4ae06010) but use different bits
ABB_IVA_DONE_ST (bit 30), ABB_DSPEVE_DONE_ST( bit 29) and
ABB_GPU_DONE_ST (but 28).

The commit b36c6b1887ff ("regulator: ti-abb: Make use of the helper
function devm_ioremap related") overlooked the following comment
implicitly explaining why devm_ioremap() is used in this case:

  /*
   * We may have shared interrupt register offsets which are
   * write-1-to-clear between domains ensuring exclusivity.
   */

Fixes and partially reverts commit b36c6b1887ff ("regulator: ti-abb:
Make use of the helper function devm_ioremap related").

Improve the existing comment to avoid further conversion to
devm_platform_ioremap_resource_byname().

Fixes: b36c6b1887ff ("regulator: ti-abb: Make use of the helper function devm_ioremap related")
Signed-off-by: Romain Naour <romain.naour@skf.com>
Reviewed-by: Yoann Congal <yoann.congal@smile.fr>
---
v2: improve commit log and update comment preventing further conversion
to devm_platform_ioremap_resource_byname().
---
 drivers/regulator/ti-abb-regulator.c | 22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/drivers/regulator/ti-abb-regulator.c b/drivers/regulator/ti-abb-regulator.c
index f48214e2c3b4..04133510e5af 100644
--- a/drivers/regulator/ti-abb-regulator.c
+++ b/drivers/regulator/ti-abb-regulator.c
@@ -726,9 +726,25 @@ static int ti_abb_probe(struct platform_device *pdev)
 			return PTR_ERR(abb->setup_reg);
 	}
 
-	abb->int_base = devm_platform_ioremap_resource_byname(pdev, "int-address");
-	if (IS_ERR(abb->int_base))
-		return PTR_ERR(abb->int_base);
+	pname = "int-address";
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, pname);
+	if (!res) {
+		dev_err(dev, "Missing '%s' IO resource\n", pname);
+		return -ENODEV;
+	}
+	/*
+	 * The MPU interrupt status register (PRM_IRQSTATUS_MPU) is
+	 * shared between regulator-abb-{ivahd,dspeve,gpu} driver
+	 * instances. Therefore use devm_ioremap() rather than
+	 * devm_platform_ioremap_resource_byname() to avoid busy
+	 * resource region conflicts.
+	 */
+	abb->int_base = devm_ioremap(dev, res->start,
+					     resource_size(res));
+	if (!abb->int_base) {
+		dev_err(dev, "Unable to map '%s'\n", pname);
+		return -ENOMEM;
+	}
 
 	/* Map Optional resources */
 	pname = "efuse-address";
-- 
2.43.0


^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH v2] regulator: ti-abb: don't use devm_platform_ioremap_resource_byname for shared interrupt register
  2024-01-23 11:14 [PATCH v2] regulator: ti-abb: don't use devm_platform_ioremap_resource_byname for shared interrupt register Romain Naour
@ 2024-01-24 18:11 ` Mark Brown
  0 siblings, 0 replies; 2+ messages in thread
From: Mark Brown @ 2024-01-24 18:11 UTC (permalink / raw)
  To: linux-kernel, linux-omap, Romain Naour
  Cc: tony, lgirdwood, Romain Naour, Yoann Congal

On Tue, 23 Jan 2024 12:14:56 +0100, Romain Naour wrote:
> We can't use devm_platform_ioremap_resource_byname() to remap the
> interrupt register that can be shared between
> regulator-abb-{ivahd,dspeve,gpu} drivers instances.
> 
> The combined helper introduce a call to devm_request_mem_region() that
> creates a new busy resource region on PRM_IRQSTATUS_MPU register
> (0x4ae06010). The first devm_request_mem_region() call succeeds for
> regulator-abb-ivahd but fails for the two other regulator-abb-dspeve
> and regulator-abb-gpu.
> 
> [...]

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator.git for-next

Thanks!

[1/1] regulator: ti-abb: don't use devm_platform_ioremap_resource_byname for shared interrupt register
      commit: a67e1f0bd4564b485e0f0c3ed7f6bf17688be268

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark


^ permalink raw reply	[flat|nested] 2+ messages in thread

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2024-01-23 11:14 [PATCH v2] regulator: ti-abb: don't use devm_platform_ioremap_resource_byname for shared interrupt register Romain Naour
2024-01-24 18:11 ` Mark Brown

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