The remoteproc driver core currently relies on iommu_present() on
the bus the device is on, to perform MMU management. However, this
logic doesn't scale for multi-arch, especially for processors that
do not have an IOMMU. Replace this logic instead by using a h/w
capability flag for the presence of IOMMU in the rproc structure.
This issue is seen on OMAP platforms when trying to add a remoteproc
driver for a small Cortex M3 called the WkupM3 used for suspend /
resume management on TI AM335/AM437x SoCs. This processor does not
have an MMU. Same is the case with another processor subsystem
PRU-ICSS on AM335/AM437x. All these are platform devices, and the
current iommu_present check will not scale for the same kernel image
to support OMAP4/OMAP5 and AM335/AM437x.
The existing platform implementation drivers - OMAP remoteproc, STE
Modem remoteproc and DA8xx remoteproc, are updated as well to properly
configure the newly added rproc field.
Cc: Robert Tivy <rtivy@xxxxxx>
Cc: Linus Walleij <linus.walleij@xxxxxxxxxx>
Signed-off-by: Suman Anna <s-anna@xxxxxx>
---
v2:
- set the field explicitly in all existing remoteproc platform drivers
- update patch description
drivers/remoteproc/da8xx_remoteproc.c | 1 +
drivers/remoteproc/omap_remoteproc.c | 5 +++++
drivers/remoteproc/remoteproc_core.c | 15 ++-------------
drivers/remoteproc/ste_modem_rproc.c | 1 +
include/linux/remoteproc.h | 2 ++
5 files changed, 11 insertions(+), 13 deletions(-)
diff --git a/drivers/remoteproc/da8xx_remoteproc.c b/drivers/remoteproc/da8xx_remoteproc.c
index 3841b98..9fdc0af 100644
--- a/drivers/remoteproc/da8xx_remoteproc.c
+++ b/drivers/remoteproc/da8xx_remoteproc.c
@@ -224,6 +224,7 @@ static int da8xx_rproc_probe(struct platform_device *pdev)
drproc = rproc->priv;
drproc->rproc = rproc;
+ rproc->has_iommu = false;
platform_set_drvdata(pdev, rproc);
diff --git a/drivers/remoteproc/omap_remoteproc.c b/drivers/remoteproc/omap_remoteproc.c
index 5168972..b21ce95 100644
--- a/drivers/remoteproc/omap_remoteproc.c
+++ b/drivers/remoteproc/omap_remoteproc.c
@@ -199,6 +199,11 @@ static int omap_rproc_probe(struct platform_device *pdev)
oproc = rproc->priv;
oproc->rproc = rproc;
+ /*
+ * All existing OMAP IPU and DSP processors do have an MMU, and
+ * are expected to use MMU, so this statement suffices.
+ */
+ rproc->has_iommu = true;
platform_set_drvdata(pdev, rproc);
diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
index 3cd85a6..11cdb11 100644
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c
@@ -94,19 +94,8 @@ static int rproc_enable_iommu(struct rproc *rproc)
struct device *dev = rproc->dev.parent;
int ret;
- /*
- * We currently use iommu_present() to decide if an IOMMU
- * setup is needed.
- *
- * This works for simple cases, but will easily fail with
- * platforms that do have an IOMMU, but not for this specific
- * rproc.
- *
- * This will be easily solved by introducing hw capabilities
- * that will be set by the remoteproc driver.
- */
- if (!iommu_present(dev->bus)) {
- dev_dbg(dev, "iommu not found\n");
+ if (!rproc->has_iommu) {
+ dev_dbg(dev, "iommu not present\n");
return 0;
}
diff --git a/drivers/remoteproc/ste_modem_rproc.c b/drivers/remoteproc/ste_modem_rproc.c
index c4ac910..c42a32e 100644
--- a/drivers/remoteproc/ste_modem_rproc.c
+++ b/drivers/remoteproc/ste_modem_rproc.c
@@ -289,6 +289,7 @@ static int sproc_probe(struct platform_device *pdev)
sproc = rproc->priv;
sproc->mdev = mdev;
sproc->rproc = rproc;
+ rproc->has_iommu = false;
mdev->drv_data = sproc;
/* Provide callback functions to modem device */
diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
index 9e7e745..78b8a9b 100644
--- a/include/linux/remoteproc.h
+++ b/include/linux/remoteproc.h
@@ -404,6 +404,7 @@ enum rproc_crash_type {
* @table_ptr: pointer to the resource table in effect
* @cached_table: copy of the resource table
* @table_csum: checksum of the resource table
+ * @has_iommu: flag to indicate if remote processor is behind an MMU
*/
struct rproc {
struct klist_node node;
@@ -435,6 +436,7 @@ struct rproc {
struct resource_table *table_ptr;
struct resource_table *cached_table;
u32 table_csum;
+ bool has_iommu;
};
/* we currently support only two vrings per rvdev */
--
2.0.4
--
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