[PATCH] remoteproc: mediatek: fix side effect of mt8195 sram power on

[Tinghan Shen]

The definition of L1TCM_SRAM_PDN bits on mt8195 is different to mt8192.

L1TCM_SRAM_PDN bits[3:0] control the power of mt8195 L1TCM SRAM.

L1TCM_SRAM_PDN bits[7:4] control the access path to EMI for SCP.
These bits have to be powered on to allow EMI access for SCP.

Bits[7:4] also affect audio DSP because audio DSP and SCP are
placed on the same hardware bus. If SCP cannot access EMI, audio DSP is
blocked too.

L1TCM_SRAM_PDN bits[31:8] are not used.

This fix removes modification of bits[7:4] when power on/off mt8195 SCP
L1TCM. It's because the modification introduces a short period of time
blocking audio DSP to access EMI. This was not a problem until we have
to load both SCP module and audio DSP module. audio DSP needs to access
EMI because it has source/data on DRAM. Audio DSP will have unexpected
behavior when it accesses EMI and the SCP driver blocks the EMI path at
the same time.

Signed-off-by: Tinghan Shen <tinghan.shen@xxxxxxxxxxxx>
---
 drivers/remoteproc/mtk_common.h |  4 +++
 drivers/remoteproc/mtk_scp.c    | 57 +++++++++++++++++++++++++++++----
 2 files changed, 55 insertions(+), 6 deletions(-)

diff --git a/drivers/remoteproc/mtk_common.h b/drivers/remoteproc/mtk_common.h
index 5ff3867c72f3..27e7172c926d 100644
--- a/drivers/remoteproc/mtk_common.h
+++ b/drivers/remoteproc/mtk_common.h
@@ -51,6 +51,10 @@
 #define MT8192_CORE0_WDT_IRQ		0x10030
 #define MT8192_CORE0_WDT_CFG		0x10034
 
+#define MT8195_L1TCM_SRAM_PDN_RESERVED_RSI_BITS		0xF0
+#define MT8195_L1TCM_SRAM_PDN_RESERVED_BITS \
+	MT8195_L1TCM_SRAM_PDN_RESERVED_RSI_BITS
+
 #define SCP_FW_VER_LEN			32
 #define SCP_SHARE_BUFFER_SIZE		288
 
diff --git a/drivers/remoteproc/mtk_scp.c b/drivers/remoteproc/mtk_scp.c
index dcddb33e9997..4d75af856fd1 100644
--- a/drivers/remoteproc/mtk_scp.c
+++ b/drivers/remoteproc/mtk_scp.c
@@ -365,22 +365,32 @@ static int mt8183_scp_before_load(struct mtk_scp *scp)
 	return 0;
 }
 
-static void mt8192_power_on_sram(void __iomem *addr)
+static void scp_sram_power_on(void __iomem *addr, u32 reserved_mask)
 {
 	int i;
 
 	for (i = 31; i >= 0; i--)
-		writel(GENMASK(i, 0), addr);
+		writel(GENMASK(i, 0) & ~reserved_mask, addr);
 	writel(0, addr);
 }
 
-static void mt8192_power_off_sram(void __iomem *addr)
+static void scp_sram_power_off(void __iomem *addr, u32 reserved_mask)
 {
 	int i;
 
 	writel(0, addr);
 	for (i = 0; i < 32; i++)
-		writel(GENMASK(i, 0), addr);
+		writel(GENMASK(i, 0) & ~reserved_mask, addr);
+}
+
+static void mt8192_power_on_sram(void __iomem *addr)
+{
+	scp_sram_power_on(addr, 0);
+}
+
+static void mt8192_power_off_sram(void __iomem *addr)
+{
+	scp_sram_power_off(addr, 0);
 }
 
 static int mt8192_scp_before_load(struct mtk_scp *scp)
@@ -403,6 +413,27 @@ static int mt8192_scp_before_load(struct mtk_scp *scp)
 	return 0;
 }
 
+static int mt8195_scp_before_load(struct mtk_scp *scp)
+{
+	/* clear SPM interrupt, SCP2SPM_IPC_CLR */
+	writel(0xff, scp->reg_base + MT8192_SCP2SPM_IPC_CLR);
+
+	writel(1, scp->reg_base + MT8192_CORE0_SW_RSTN_SET);
+
+	/* enable SRAM clock */
+	mt8192_power_on_sram(scp->reg_base + MT8192_L2TCM_SRAM_PD_0);
+	mt8192_power_on_sram(scp->reg_base + MT8192_L2TCM_SRAM_PD_1);
+	mt8192_power_on_sram(scp->reg_base + MT8192_L2TCM_SRAM_PD_2);
+	scp_sram_power_on(scp->reg_base + MT8192_L1TCM_SRAM_PDN,
+			  MT8195_L1TCM_SRAM_PDN_RESERVED_BITS);
+	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;
+}
+
 static int scp_load(struct rproc *rproc, const struct firmware *fw)
 {
 	struct mtk_scp *scp = rproc->priv;
@@ -561,6 +592,20 @@ static void mt8192_scp_stop(struct mtk_scp *scp)
 	writel(0, scp->reg_base + MT8192_CORE0_WDT_CFG);
 }
 
+static void mt8195_scp_stop(struct mtk_scp *scp)
+{
+	/* Disable SRAM clock */
+	mt8192_power_off_sram(scp->reg_base + MT8192_L2TCM_SRAM_PD_0);
+	mt8192_power_off_sram(scp->reg_base + MT8192_L2TCM_SRAM_PD_1);
+	mt8192_power_off_sram(scp->reg_base + MT8192_L2TCM_SRAM_PD_2);
+	scp_sram_power_off(scp->reg_base + MT8192_L1TCM_SRAM_PDN,
+			   MT8195_L1TCM_SRAM_PDN_RESERVED_BITS);
+	mt8192_power_off_sram(scp->reg_base + MT8192_CPU0_SRAM_PD);
+
+	/* Disable SCP watchdog */
+	writel(0, scp->reg_base + MT8192_CORE0_WDT_CFG);
+}
+
 static int scp_stop(struct rproc *rproc)
 {
 	struct mtk_scp *scp = (struct mtk_scp *)rproc->priv;
@@ -888,11 +933,11 @@ static const struct mtk_scp_of_data mt8192_of_data = {
 
 static const struct mtk_scp_of_data mt8195_of_data = {
 	.scp_clk_get = mt8195_scp_clk_get,
-	.scp_before_load = mt8192_scp_before_load,
+	.scp_before_load = mt8195_scp_before_load,
 	.scp_irq_handler = mt8192_scp_irq_handler,
 	.scp_reset_assert = mt8192_scp_reset_assert,
 	.scp_reset_deassert = mt8192_scp_reset_deassert,
-	.scp_stop = mt8192_scp_stop,
+	.scp_stop = mt8195_scp_stop,
 	.scp_da_to_va = mt8192_scp_da_to_va,
 	.host_to_scp_reg = MT8192_GIPC_IN_SET,
 	.host_to_scp_int_bit = MT8192_HOST_IPC_INT_BIT,
-- 
2.18.0