On 11/01/2022 07:39, Yong Wu wrote:
> Sleep control means that when the larb goes to sleep, we should wait a bit
> until all the current commands are finished. Thus, when the larb runtime
> suspends, we need to enable this function to wait until all the existed
> commands are finished. When the larb resumes, just disable this function.
> This function only improves the safety of bus. Add a new flag for this
> function. Prepare for mt8186.
>
> Signed-off-by: Anan Sun <anan....@mediatek.com>
> Signed-off-by: Yong Wu <yong...@mediatek.com>
> ---
> drivers/memory/mtk-smi.c | 35 ++++++++++++++++++++++++++++++++++-
> 1 file changed, 34 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/memory/mtk-smi.c b/drivers/memory/mtk-smi.c
> index e7b1a22b12ea..d8552f4caba4 100644
> --- a/drivers/memory/mtk-smi.c
> +++ b/drivers/memory/mtk-smi.c
> @@ -8,6 +8,7 @@
> #include <linux/device.h>
> #include <linux/err.h>
> #include <linux/io.h>
> +#include <linux/iopoll.h>
> #include <linux/module.h>
> #include <linux/of.h>
> #include <linux/of_platform.h>
> @@ -32,6 +33,10 @@
> #define SMI_DUMMY 0x444
>
> /* SMI LARB */
> +#define SMI_LARB_SLP_CON 0xc
> +#define SLP_PROT_EN BIT(0)
> +#define SLP_PROT_RDY BIT(16)
> +
> #define SMI_LARB_CMD_THRT_CON 0x24
> #define SMI_LARB_THRT_RD_NU_LMT_MSK GENMASK(7, 4)
> #define SMI_LARB_THRT_RD_NU_LMT (5 << 4)
> @@ -81,6 +86,7 @@
>
> #define MTK_SMI_FLAG_THRT_UPDATE BIT(0)
> #define MTK_SMI_FLAG_SW_FLAG BIT(1)
> +#define MTK_SMI_FLAG_SLEEP_CTL BIT(2)
> #define MTK_SMI_CAPS(flags, _x) (!!((flags) & (_x)))
>
> struct mtk_smi_reg_pair {
> @@ -371,6 +377,26 @@ static const struct of_device_id mtk_smi_larb_of_ids[] =
> {
> {}
> };
>
> +static int mtk_smi_larb_sleep_ctrl_enable(struct mtk_smi_larb *larb)
> +{
> + int ret;
> + u32 tmp;
> +
> + writel_relaxed(SLP_PROT_EN, larb->base + SMI_LARB_SLP_CON);
> + ret = readl_poll_timeout_atomic(larb->base + SMI_LARB_SLP_CON,
> + tmp, !!(tmp & SLP_PROT_RDY), 10, 1000);
> + if (ret) {
> + /* TODO: Reset this larb if it fails here. */
> + dev_warn(larb->smi.dev, "sleep ctrl is not ready(0x%x).\n",
> tmp);
> + }
> + return ret;
> +}
> +
> +static void mtk_smi_larb_sleep_ctrl_disable(struct mtk_smi_larb *larb)
> +{
> + writel_relaxed(0, larb->base + SMI_LARB_SLP_CON);
> +}
> +
> static int mtk_smi_device_link_common(struct device *dev, struct device
> **com_dev)
> {
> struct platform_device *smi_com_pdev;
> @@ -483,6 +509,9 @@ static int __maybe_unused mtk_smi_larb_resume(struct
> device *dev)
> if (ret)
> return ret;
>
> + if (MTK_SMI_CAPS(larb->larb_gen->flags_general, MTK_SMI_FLAG_SLEEP_CTL))
> + mtk_smi_larb_sleep_ctrl_disable(larb);
> +
> /* Configure the basic setting for this larb */
> larb_gen->config_port(dev);
>
> @@ -492,9 +521,13 @@ static int __maybe_unused mtk_smi_larb_resume(struct
> device *dev)
> static int __maybe_unused mtk_smi_larb_suspend(struct device *dev)
> {
> struct mtk_smi_larb *larb = dev_get_drvdata(dev);
> + int ret = 0;
> +
> + if (MTK_SMI_CAPS(larb->larb_gen->flags_general, MTK_SMI_FLAG_SLEEP_CTL))
> + ret = mtk_smi_larb_sleep_ctrl_enable(larb);
>
> clk_bulk_disable_unprepare(larb->smi.clk_num, larb->smi.clks);
> - return 0;
> + return ret;
I am wondering whether disabling clocks in error case is a proper step.
On suspend error, the PM core won't run any further callbacks on this
device. This means, it won't be resumed and your clocks stay disabled. I
think you should return early and leave the device in active state in
case of error.
Best regards,
Krzysztof
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