remoteproc/mediatek: enable MPU for all memory regions in MT8192 SCP

The register MT8192_CORE0_MEM_ATT_PREDEF contains attributes for each
memory region.  It defines whether a memory region can be managed by MPU
or not.

In the past, due to the default settings in the register, MT8192 SCP
works luckily.  After enabling L1TCM, SCP starts to access memory region
that is not included in the default settings.  As a result, SCP hangs.

Enables MPU for all memory regions in MT8192 SCP.

Note that the register is read only once when SCP resets.  Thus, it must
be set from kernel side.

Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Tzung-Bi Shih <tzungbi@google.com>
Link: https://lore.kernel.org/r/20210127083136.3745652-3-tzungbi@google.com
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

diff --git a/drivers/remoteproc/mtk_common.h b/drivers/remoteproc/mtk_common.h
index bcab38511bf318ba48addfe63e6f39c9189f91f9..204691138677fa7ca19467d77beaa5b52ce2c111 100644 (file)
--- a/drivers/remoteproc/mtk_common.h
+++ b/drivers/remoteproc/mtk_common.h
@@ -47,6 +47,7 @@
 
 #define MT8192_CORE0_SW_RSTN_CLR       0x10000
 #define MT8192_CORE0_SW_RSTN_SET       0x10004
+#define MT8192_CORE0_MEM_ATT_PREDEF    0x10008
 #define MT8192_CORE0_WDT_IRQ           0x10030
 #define MT8192_CORE0_WDT_CFG           0x10034
 

diff --git a/drivers/remoteproc/mtk_scp.c b/drivers/remoteproc/mtk_scp.c
index d83e1164f02fa0a44b32c0e9ff6b5621fdfd4af2..05b15768912150622f3d2624a8c02440fd5afbf1 100644 (file)
--- a/drivers/remoteproc/mtk_scp.c
+++ b/drivers/remoteproc/mtk_scp.c
@@ -371,6 +371,9 @@ static int mt8192_scp_before_load(struct mtk_scp *scp)
        mt8192_power_on_sram(scp->reg_base + MT8192_L1TCM_SRAM_PDN);
        mt8192_power_on_sram(scp->reg_base + MT8192_CPU0_SRAM_PD);
 
+       /* enable MPU for all memory regions */
+       writel(0xff, scp->reg_base + MT8192_CORE0_MEM_ATT_PREDEF);
+
        return 0;
 }