Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/arc/mm/cache.c b/arch/arc/mm/cache.c
index f2701c1..a2fbea3 100644
--- a/arch/arc/mm/cache.c
+++ b/arch/arc/mm/cache.c
@@ -1,12 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
* ARC Cache Management
*
* Copyright (C) 2014-15 Synopsys, Inc. (www.synopsys.com)
* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
*/
#include <linux/module.h>
@@ -113,10 +110,24 @@
}
READ_BCR(ARC_REG_CLUSTER_BCR, cbcr);
- if (cbcr.c)
+ if (cbcr.c) {
ioc_exists = 1;
- else
+
+ /*
+ * As for today we don't support both IOC and ZONE_HIGHMEM enabled
+ * simultaneously. This happens because as of today IOC aperture covers
+ * only ZONE_NORMAL (low mem) and any dma transactions outside this
+ * region won't be HW coherent.
+ * If we want to use both IOC and ZONE_HIGHMEM we can use
+ * bounce_buffer to handle dma transactions to HIGHMEM.
+ * Also it is possible to modify dma_direct cache ops or increase IOC
+ * aperture size if we are planning to use HIGHMEM without PAE.
+ */
+ if (IS_ENABLED(CONFIG_HIGHMEM) || is_pae40_enabled())
+ ioc_enable = 0;
+ } else {
ioc_enable = 0;
+ }
/* HS 2.0 didn't have AUX_VOL */
if (cpuinfo_arc700[cpu].core.family > 0x51) {
@@ -1145,17 +1156,18 @@
unsigned int ioc_base, mem_sz;
/*
- * As for today we don't support both IOC and ZONE_HIGHMEM enabled
- * simultaneously. This happens because as of today IOC aperture covers
- * only ZONE_NORMAL (low mem) and any dma transactions outside this
- * region won't be HW coherent.
- * If we want to use both IOC and ZONE_HIGHMEM we can use
- * bounce_buffer to handle dma transactions to HIGHMEM.
- * Also it is possible to modify dma_direct cache ops or increase IOC
- * aperture size if we are planning to use HIGHMEM without PAE.
+ * If IOC was already enabled (due to bootloader) it technically needs to
+ * be reconfigured with aperture base,size corresponding to Linux memory map
+ * which will certainly be different than uboot's. But disabling and
+ * reenabling IOC when DMA might be potentially active is tricky business.
+ * To avoid random memory issues later, just panic here and ask user to
+ * upgrade bootloader to one which doesn't enable IOC
*/
- if (IS_ENABLED(CONFIG_HIGHMEM))
- panic("IOC and HIGHMEM can't be used simultaneously");
+ if (read_aux_reg(ARC_REG_IO_COH_ENABLE) & ARC_IO_COH_ENABLE_BIT)
+ panic("IOC already enabled, please upgrade bootloader!\n");
+
+ if (!ioc_enable)
+ return;
/* Flush + invalidate + disable L1 dcache */
__dc_disable();
@@ -1187,8 +1199,8 @@
panic("IOC Aperture start must be aligned to the size of the aperture");
write_aux_reg(ARC_REG_IO_COH_AP0_BASE, ioc_base >> 12);
- write_aux_reg(ARC_REG_IO_COH_PARTIAL, 1);
- write_aux_reg(ARC_REG_IO_COH_ENABLE, 1);
+ write_aux_reg(ARC_REG_IO_COH_PARTIAL, ARC_IO_COH_PARTIAL_BIT);
+ write_aux_reg(ARC_REG_IO_COH_ENABLE, ARC_IO_COH_ENABLE_BIT);
/* Re-enable L1 dcache */
__dc_enable();
@@ -1265,7 +1277,7 @@
if (is_isa_arcv2() && l2_line_sz && !slc_enable)
arc_slc_disable();
- if (is_isa_arcv2() && ioc_enable)
+ if (is_isa_arcv2() && ioc_exists)
arc_ioc_setup();
if (is_isa_arcv2() && l2_line_sz && slc_enable) {
@@ -1280,7 +1292,7 @@
/*
* In case of IOC (say IOC+SLC case), pointers above could still be set
* but end up not being relevant as the first function in chain is not
- * called at all for @dma_direct_ops
+ * called at all for devices using coherent DMA.
* arch_sync_dma_for_cpu() -> dma_cache_*() -> __dma_cache_*()
*/
}