remoteproc: add IOMMU hardware capability flag

The remoteproc framework 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@ti.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Suman Anna <s-anna@ti.com>
[small change in the commit title and in a single comment]
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
index 9e7e745dac55..78b8a9b9d40a 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 */