[PATCH v3 09/11] remoteproc: mediatek: Setup MT8195 SCP core 1 SRAM offset

[Tinghan Shen]

Because MT8195 SCP core 0 and core 1 both boot from head of SRAM and
have the same viewpoint of SRAM, SCP has a "Core 1 SRAM offset"
to control the viewpoint of SCP core 1 to allow core 1 boot
from different SRAM location.

The "Core 1 SRAM offset" configuration is composed by specifying a range
and an offset. When SCP core 1 accesses a SRAM address located in the
configured range, SCP bus adds the configured offset to the address to
shift the final physical destination on SCP SRAM. This shift is
transparent to the software running on SCP core 1.

Signed-off-by: Tinghan Shen <tinghan.shen at mediatek.com>
---
 drivers/remoteproc/mtk_scp.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/drivers/remoteproc/mtk_scp.c b/drivers/remoteproc/mtk_scp.c
index 2d43338b96da..0f1b587f8502 100644
--- a/drivers/remoteproc/mtk_scp.c
+++ b/drivers/remoteproc/mtk_scp.c
@@ -477,6 +477,8 @@ static int mt8195_scp_before_load(struct mtk_scp *scp)
 
 static int mt8195_scp_c1_before_load(struct mtk_scp *scp)
 {
+	u32 sec_ctrl;
+
 	scp_sram_power_on(scp->reg_base + MT8195_CPU1_SRAM_PD, 0);
 
 	/* hold SCP in reset while loading FW. */
@@ -485,6 +487,27 @@ static int mt8195_scp_c1_before_load(struct mtk_scp *scp)
 	/* enable MPU for all memory regions */
 	writel(0xff, scp->reg_base + MT8195_CORE1_MEM_ATT_PREDEF);
 
+	/* The value of SRAM offset range is from the viewpoint of SCP core 1.
+	 * This configuration adds an offset on SCP bus when SCP core 1 accesses SCP SRAM
+	 * to solve the SCP core 0 and core 1 both fetch the 1st instruction from the same
+	 * SRAM address.
+	 *
+	 * Because SCP core 0 and core 1 both boot from the head of sram, this must be
+	 * configured before boot SCP core 1.
+	 *
+	 * Configure the range of SRAM addresses will be added offset.
+	 */
+	writel(0, scp->reg_base + MT8195_L2TCM_OFFSET_RANGE_0_LOW);
+	writel(scp->sram_size, scp->reg_base + MT8195_L2TCM_OFFSET_RANGE_0_HIGH);
+
+	/* configure the offset value */
+	writel(scp->sram_phys - scp->main_scp->sram_phys, scp->reg_base + MT8195_L2TCM_OFFSET);
+
+	/* enable adding sram offset when fetching instruction and data */
+	sec_ctrl = readl(scp->reg_base + MT8195_SEC_CTRL);
+	sec_ctrl |= MT8195_CORE_OFFSET_ENABLE_I | MT8195_CORE_OFFSET_ENABLE_D;
+	writel(sec_ctrl, scp->reg_base + MT8195_SEC_CTRL);
+
 	return 0;
 }
 
-- 
2.18.0