remoteproc: mediatek: Fix side effect of mt8195 sram power on

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.

Fixes: 79111df4 ("remoteproc: mediatek: Support mt8195 scp")
Signed-off-by: Tinghan Shen <tinghan.shen@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Link: https://lore.kernel.org/r/20220321060340.10975-1-tinghan.shen@mediatek.comSigned-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

drivers/remoteproc/mtk_common.h

@@ -54,6 +54,8 @@
 #define MT8192_CORE0_WDT_IRQ		0x10030
 #define MT8192_CORE0_WDT_CFG		0x10034
 
+#define MT8195_L1TCM_SRAM_PDN_RESERVED_RSI_BITS		GENMASK(7, 4)
+
 #define SCP_FW_VER_LEN			32
 #define SCP_SHARE_BUFFER_SIZE		288
 

drivers/remoteproc/mtk_scp.c

@@ -365,22 +365,22 @@ 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 int mt8186_scp_before_load(struct mtk_scp *scp)
@@ -393,7 +393,7 @@ static int mt8186_scp_before_load(struct mtk_scp *scp)
 	writel(0x0, scp->reg_base + MT8183_SCP_CLK_DIV_SEL);
 
 	/* Turn on the power of SCP's SRAM before using it. Enable 1 block per time*/
-	mt8192_power_on_sram(scp->reg_base + MT8183_SCP_SRAM_PDN);
+	scp_sram_power_on(scp->reg_base + MT8183_SCP_SRAM_PDN, 0);
 
 	/* Initialize TCM before loading FW. */
 	writel(0x0, scp->reg_base + MT8183_SCP_L1_SRAM_PD);
@@ -412,11 +412,32 @@ static int mt8192_scp_before_load(struct mtk_scp *scp)
 	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);
-	mt8192_power_on_sram(scp->reg_base + MT8192_L1TCM_SRAM_PDN);
-	mt8192_power_on_sram(scp->reg_base + MT8192_CPU0_SRAM_PD);
+	scp_sram_power_on(scp->reg_base + MT8192_L2TCM_SRAM_PD_0, 0);
+	scp_sram_power_on(scp->reg_base + MT8192_L2TCM_SRAM_PD_1, 0);
+	scp_sram_power_on(scp->reg_base + MT8192_L2TCM_SRAM_PD_2, 0);
+	scp_sram_power_on(scp->reg_base + MT8192_L1TCM_SRAM_PDN, 0);
+	scp_sram_power_on(scp->reg_base + MT8192_CPU0_SRAM_PD, 0);
+
+	/* enable MPU for all memory regions */
+	writel(0xff, scp->reg_base + MT8192_CORE0_MEM_ATT_PREDEF);
+
+	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 */
+	scp_sram_power_on(scp->reg_base + MT8192_L2TCM_SRAM_PD_0, 0);
+	scp_sram_power_on(scp->reg_base + MT8192_L2TCM_SRAM_PD_1, 0);
+	scp_sram_power_on(scp->reg_base + MT8192_L2TCM_SRAM_PD_2, 0);
+	scp_sram_power_on(scp->reg_base + MT8192_L1TCM_SRAM_PDN,
+			  MT8195_L1TCM_SRAM_PDN_RESERVED_RSI_BITS);
+	scp_sram_power_on(scp->reg_base + MT8192_CPU0_SRAM_PD, 0);
 
 	/* enable MPU for all memory regions */
 	writel(0xff, scp->reg_base + MT8192_CORE0_MEM_ATT_PREDEF);
@@ -572,11 +593,25 @@ static void mt8183_scp_stop(struct mtk_scp *scp)
 static void mt8192_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);
-	mt8192_power_off_sram(scp->reg_base + MT8192_L1TCM_SRAM_PDN);
-	mt8192_power_off_sram(scp->reg_base + MT8192_CPU0_SRAM_PD);
+	scp_sram_power_off(scp->reg_base + MT8192_L2TCM_SRAM_PD_0, 0);
+	scp_sram_power_off(scp->reg_base + MT8192_L2TCM_SRAM_PD_1, 0);
+	scp_sram_power_off(scp->reg_base + MT8192_L2TCM_SRAM_PD_2, 0);
+	scp_sram_power_off(scp->reg_base + MT8192_L1TCM_SRAM_PDN, 0);
+	scp_sram_power_off(scp->reg_base + MT8192_CPU0_SRAM_PD, 0);
+
+	/* Disable SCP watchdog */
+	writel(0, scp->reg_base + MT8192_CORE0_WDT_CFG);
+}
+
+static void mt8195_scp_stop(struct mtk_scp *scp)
+{
+	/* Disable SRAM clock */
+	scp_sram_power_off(scp->reg_base + MT8192_L2TCM_SRAM_PD_0, 0);
+	scp_sram_power_off(scp->reg_base + MT8192_L2TCM_SRAM_PD_1, 0);
+	scp_sram_power_off(scp->reg_base + MT8192_L2TCM_SRAM_PD_2, 0);
+	scp_sram_power_off(scp->reg_base + MT8192_L1TCM_SRAM_PDN,
+			   MT8195_L1TCM_SRAM_PDN_RESERVED_RSI_BITS);
+	scp_sram_power_off(scp->reg_base + MT8192_CPU0_SRAM_PD, 0);
 
 	/* Disable SCP watchdog */
 	writel(0, scp->reg_base + MT8192_CORE0_WDT_CFG);
@@ -922,11 +957,11 @@ 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,