Re: [PATCH v5] remoteproc: mediatek: Fix side effect of mt8195 sram power on

From: Mathieu Poirier
Date: Fri Mar 18 2022 - 12:41:10 EST

On Fri, Mar 18, 2022 at 07:42:00PM +0800, Tinghan Shen wrote:
> 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: 79111df414fc ("remoteproc: mediatek: Support mt8195 scp")
> Signed-off-by: Tinghan Shen <tinghan.shen@xxxxxxxxxxxx>
> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
> Reviewed-by: Matthias Brugger <matthias.bgg@xxxxxxxxx>
>
> ---
> v5: rebased on rproc-next
> v4: add Fixes and Reviewed-by tags
> v3: fix build error
> v2: apply comments about macro definition and function calls
> ---
> drivers/remoteproc/mtk_common.h | 2 +
> drivers/remoteproc/mtk_scp.c | 67 +++++++++++++++++++++++++--------
> 2 files changed, 53 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/remoteproc/mtk_common.h b/drivers/remoteproc/mtk_common.h
> index 71ce4977cb0b..ea6fa1100a00 100644
> --- a/drivers/remoteproc/mtk_common.h
> +++ b/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
>
> diff --git a/drivers/remoteproc/mtk_scp.c b/drivers/remoteproc/mtk_scp.c
> index 38609153bf64..068edf21ea51 100644
> --- a/drivers/remoteproc/mtk_scp.c
> +++ b/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)
> @@ -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,


GEN Makefile
UPD include/config/kernel.release
UPD include/generated/utsrelease.h
CALL /home/mpoirier/work/remoteproc/kernel-review/scripts/atomic/check-atomics.sh
CALL /home/mpoirier/work/remoteproc/kernel-review/scripts/checksyscalls.sh
CHK include/generated/compile.h
CC init/version.o
AR init/built-in.a
CC kernel/sys.o
CC net/ethtool/ioctl.o
CC kernel/module.o
CC kernel/trace/trace.o
CC drivers/base/firmware_loader/main.o
CC drivers/base/firmware_loader/builtin/main.o
AR net/ethtool/built-in.a
AR drivers/base/firmware_loader/builtin/built-in.a
AR net/built-in.a
AR drivers/base/firmware_loader/built-in.a
AR drivers/base/built-in.a
CC drivers/remoteproc/mtk_scp.o
CC drivers/remoteproc/mtk_scp_ipi.o
CC drivers/ras/ras.o
CC drivers/remoteproc/stm32_rproc.o
CC drivers/nvmem/core.o
AR kernel/trace/built-in.a
AR kernel/built-in.a
/home/mpoirier/work/remoteproc/kernel-review/drivers/remoteproc/mtk_scp.c: In function ‘mt8186_scp_before_load’:
/home/mpoirier/work/remoteproc/kernel-review/drivers/remoteproc/mtk_scp.c:396:2: error: implicit declaration of function ‘mt8192_power_on_sram’ [-Werror=implicit-function-declaration]
396 | mt8192_power_on_sram(scp->reg_base + MT8183_SCP_SRAM_PDN);
| ^~~~~~~~~~~~~~~~~~~~
...

No need to send me another revision right away - I won't apply your code for
this merge window.

> --
> 2.18.0
>