Add bridged amplifiers to cs42l43

Merge series from Charles Keepax <[email protected]>:

In some cs42l43 systems a couple of cs35l56 amplifiers are attached
to the cs42l43's SPI and I2S. On Windows the cs42l43 is controlled
by a SDCA class driver and these two amplifiers are controlled by
firmware running on the cs42l43. However, under Linux the decision
was made to interact with the cs42l43 directly, affording the user
greater control over the audio system. However, this has resulted
in an issue where these two bridged cs35l56 amplifiers are not
populated in ACPI and must be added manually. There is at least an
SDCA extension unit DT entry we can key off.

The process of adding this is handled using a software node, firstly the
ability to add native chip selects to software nodes must be added.
Secondly, an additional flag for naming the SPI devices is added this
allows the machine driver to key to the correct amplifier. Then finally,
the cs42l43 SPI driver adds the two amplifiers directly onto its SPI
bus.

An additional series will follow soon to add the audio machine driver
parts (in the sof-sdw driver), however that is fairly orthogonal to
this part of the process, getting the actual amplifiers registered.

1 files changed, 8 insertions, 6 deletions

diff --git a/mm/gup.c b/mm/gup.c
index df83182ec72d..af8edadc05d1 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1653,20 +1653,22 @@ long populate_vma_page_range(struct vm_area_struct *vma,
 	if (vma->vm_flags & VM_LOCKONFAULT)
 		return nr_pages;
 
+	/* ... similarly, we've never faulted in PROT_NONE pages */
+	if (!vma_is_accessible(vma))
+		return -EFAULT;
+
 	gup_flags = FOLL_TOUCH;
 	/*
 	 * We want to touch writable mappings with a write fault in order
 	 * to break COW, except for shared mappings because these don't COW
 	 * and we would not want to dirty them for nothing.
+	 *
+	 * Otherwise, do a read fault, and use FOLL_FORCE in case it's not
+	 * readable (ie write-only or executable).
 	 */
 	if ((vma->vm_flags & (VM_WRITE | VM_SHARED)) == VM_WRITE)
 		gup_flags |= FOLL_WRITE;
-
-	/*
-	 * We want mlock to succeed for regions that have any permissions
-	 * other than PROT_NONE.
-	 */
-	if (vma_is_accessible(vma))
+	else
 		gup_flags |= FOLL_FORCE;
 
 	if (locked)