[PATCH 1/3] acpi: Add helper for deactivating memory region

[PATCH 1/3] acpi: Add helper for deactivating memory region

[Heikki Krogerus]

Sometimes memory resource may be overlapping with
SystemMemory Operation Region by design, for example if the
memory region is used as a mailbox for communication with a
firmware in the system. One occasion of such mailboxes is
USB Type-C Connector System Software Interface (UCSI).

With regions like that, it is important that the driver is
able to map the memory with the requirements it has. For
example, the driver should be allowed to map the memory as
non-cached memory. However, if the operation region has been
accessed before the driver has mapped the memory, the memory
has been marked as write-back by the time the driver is
loaded. That means the driver will fail to map the memory
if it expects non-cached memory.

To work around the problem, introducing helper that the
drivers can use to temporarily deactivate (unmap)
SystemMemory Operation Regions that overlap with their
IO memory.

Fixes: 8243edf44152 ("usb: typec: ucsi: Add ACPI driver")
Cc: stable@vger.kernel.org
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
 drivers/acpi/osl.c   | 72 ++++++++++++++++++++++++++++++++++++++++++++
 include/linux/acpi.h |  3 ++
 2 files changed, 75 insertions(+)

diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index 7ca41bf023c9..8df9abfa947b 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -45,6 +45,8 @@
 #include <linux/uaccess.h>
 #include <linux/io-64-nonatomic-lo-hi.h>
 
+#include "acpica/accommon.h"
+#include "acpica/acnamesp.h"
 #include "internal.h"
 
 #define _COMPONENT		ACPI_OS_SERVICES
@@ -1490,6 +1492,76 @@ int acpi_check_region(resource_size_t start, resource_size_t n,
 }
 EXPORT_SYMBOL(acpi_check_region);
 
+static acpi_status acpi_deactivate_mem_region(acpi_handle handle, u32 level,
+					      void *_res, void **return_value)
+{
+	struct acpi_mem_space_context **mem_ctx;
+	union acpi_operand_object *handler_obj;
+	union acpi_operand_object *region_obj2;
+	union acpi_operand_object *region_obj;
+	struct resource *res = _res;
+	acpi_status status;
+
+	region_obj = acpi_ns_get_attached_object(handle);
+	if (!region_obj)
+		return AE_OK;
+
+	handler_obj = region_obj->region.handler;
+	if (!handler_obj)
+		return AE_OK;
+
+	if (region_obj->region.space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY)
+		return AE_OK;
+
+	if (!(region_obj->region.flags & AOPOBJ_SETUP_COMPLETE))
+		return AE_OK;
+
+	region_obj2 = acpi_ns_get_secondary_object(region_obj);
+	if (!region_obj2)
+		return AE_OK;
+
+	mem_ctx = (void *)&region_obj2->extra.region_context;
+
+	if (!(mem_ctx[0]->address >= res->start &&
+	      mem_ctx[0]->address < res->end))
+		return AE_OK;
+
+	status = handler_obj->address_space.setup(region_obj,
+						  ACPI_REGION_DEACTIVATE,
+						  NULL, (void **)mem_ctx);
+	if (ACPI_SUCCESS(status))
+		region_obj->region.flags &= ~(AOPOBJ_SETUP_COMPLETE);
+
+	return status;
+}
+
+/**
+ * acpi_release_memory - Release any mappings done to a memory region
+ * @handle: Handle to namespace node
+ * @res: Memory resource
+ * @level: A level that terminates the search
+ *
+ * Walks through @handle and unmaps all SystemMemory Operation Regions that
+ * overlap with @res and that have already been activated (mapped).
+ *
+ * This is a helper that allows drivers to place special requirements on memory
+ * region that may overlap with operation regions, primarily allowing them to
+ * safely map the region as non-cached memory.
+ *
+ * The unmapped Operation Regions will be automatically remapped next time they
+ * are called, so the drivers do not need to do anything else.
+ */
+acpi_status acpi_release_memory(acpi_handle handle, struct resource *res,
+				u32 level)
+{
+	if (!(res->flags & IORESOURCE_MEM))
+		return AE_TYPE;
+
+	return acpi_walk_namespace(ACPI_TYPE_REGION, handle, level,
+				   acpi_deactivate_mem_region, NULL, res, NULL);
+}
+EXPORT_SYMBOL_GPL(acpi_release_memory);
+
 /*
  * Let drivers know whether the resource checks are effective
  */
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 4b35a66383f9..e54f40974eb0 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -443,6 +443,9 @@ int acpi_check_resource_conflict(const struct resource *res);
 int acpi_check_region(resource_size_t start, resource_size_t n,
 		      const char *name);
 
+acpi_status acpi_release_memory(acpi_handle handle, struct resource *res,
+				u32 level);
+
 int acpi_resources_are_enforced(void);
 
 #ifdef CONFIG_HIBERNATION
-- 
2.17.1

[PATCH 2/3] usb: typec: ucsi: acpi: Workaround for cache mode issue

[Heikki Krogerus]

This fixes an issue where the driver fails with an error:

	ioremap error for 0x3f799000-0x3f79a000, requested 0x2, got 0x0

On some platforms the UCSI ACPI mailbox SystemMemory
Operation Region may be setup before the driver has been
loaded. That will lead into the driver failing to map the
mailbox region, as it has been already marked as write-back
memory. acpi_os_ioremap() for x86 uses ioremap_cache()
unconditionally.

When the issue happens, the embedded controller has a
pending query event for the UCSI notification right after
boot-up which causes the operation region to be setup before
UCSI driver has been loaded.

The fix is to notify acpi core that the driver is about to
access memory region which potentially overlaps with an
operation region right before mapping it.
acpi_release_memory() will check if the memory has already
been setup (mapped) by acpi core, and deactivate it (unmap)
if it has. The driver is then able to map the memory with
ioremap_nocache() and set the memtype to uncached for the
region.

Reported-by: Paul Menzel <pmenzel@molgen.mpg.de>
Fixes: 8243edf44152 ("usb: typec: ucsi: Add ACPI driver")
Cc: stable@vger.kernel.org
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
 drivers/usb/typec/ucsi/ucsi_acpi.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/usb/typec/ucsi/ucsi_acpi.c b/drivers/usb/typec/ucsi/ucsi_acpi.c
index 44eb4e1ea817..a18112a83fae 100644
--- a/drivers/usb/typec/ucsi/ucsi_acpi.c
+++ b/drivers/usb/typec/ucsi/ucsi_acpi.c
@@ -79,6 +79,11 @@ static int ucsi_acpi_probe(struct platform_device *pdev)
 		return -ENODEV;
 	}
 
+	/* This will make sure we can use ioremap_nocache() */
+	status = acpi_release_memory(ACPI_HANDLE(&pdev->dev), res, 1);
+	if (ACPI_FAILURE(status))
+		return -ENOMEM;
+
 	/*
 	 * NOTE: The memory region for the data structures is used also in an
 	 * operation region, which means ACPI has already reserved it. Therefore
-- 
2.17.1