staging: vc04_services: Remove cache-line-size property (v3)

It's been tempting to replace this with (L1) cache_line_size(), but
that's really not what the value is about.  It's about coordinating
the condition for the pagelist fragment behavior between the two
sides.  However, the property was not accepted for the upstream DT
binding, so we have to use the firmware's fallback value.

Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
index b59ef14890aa3a498e0356bde6f37a353e3f3b22..afdd3e944f3f10e5f554010290d5b0015bcf0bda 100644 (file)
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
@@ -77,7 +77,17 @@ struct vchiq_pagelist_info {
 };
 
 static void __iomem *g_regs;
-static unsigned int g_cache_line_size = sizeof(CACHE_LINE_SIZE);
+/* This value is the size of the L2 cache lines as understood by the
+ * VPU firmware, which determines the required alignment of the
+ * offsets/sizes in pagelists.
+ *
+ * Modern VPU firmware looks for a DT "cache-line-size" property in
+ * the VCHIQ node and will overwrite it with the actual L2 cache size,
+ * which the kernel must then respect.  That property was rejected
+ * upstream, so we have to use the VPU firmware's compatibility value
+ * of 32.
+ */
+static unsigned int g_cache_line_size = 32;
 static unsigned int g_fragments_size;
 static char *g_fragments_base;
 static char *g_free_fragments;
@@ -117,14 +127,6 @@ int vchiq_platform_init(struct platform_device *pdev, VCHIQ_STATE_T *state)
        if (err < 0)
                return err;
 
-       err = of_property_read_u32(dev->of_node, "cache-line-size",
-                                  &g_cache_line_size);
-
-       if (err) {
-               dev_err(dev, "Missing cache-line-size property\n");
-               return -ENODEV;
-       }
-
        g_fragments_size = 2 * g_cache_line_size;
 
        /* Allocate space for the channels in coherent memory */

diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_pagelist.h b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_pagelist.h
index a6c5f7cc78f0b9144f04923f872f394d0b42c221..bec411061554c53f688b9043e6ada8814b394050 100644 (file)
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_pagelist.h
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_pagelist.h
@@ -34,7 +34,6 @@
 #ifndef VCHIQ_PAGELIST_H
 #define VCHIQ_PAGELIST_H
 
-#define CACHE_LINE_SIZE 32
 #define PAGELIST_WRITE 0
 #define PAGELIST_READ 1
 #define PAGELIST_READ_WITH_FRAGMENTS 2