On Tue, Nov 19, 2024 at 03:07:26PM +0200, Daniel Baluta wrote:
> This is a RFC patch in order to allow AHB to IP Bridge (AIPSTZ)
> configuration to be restored after a suspend/resume operation.
>
> This is particularly useful for aips5 bus where the aipstz
> configuration is lost at suspend.
>
> In order to configure aipstz bridge we register a platform driver
> that will set default configuration permission at probe.
>
> Because AIPS configuration is lost at suspend/resume time we register
> a power notifier callback that will take care of re-initializing the
> configuration at resume.
why not use suspend/resume callback? what's happen if devices under AIPS
suspend/resume before AIPS resume function.
>
> More details about AHB to IP Bridge:
>
> This peripheral is designated as the bridge between AHB bus and
> peripherals with the lower bandwidth IP Slave (IPS) buses.
>
> The bridge is responsible for indicating to IPS peripherals if
> an access is in supervisor or user mode. It may block user mode
> accesses to certain IPS peripherals or it may allow the individual
> IPS peripherals to determine if user mode accesses are allowed.
>
> The bridge supports the notion of "trusted" masters for security
> purposes. Masters may be individually designated as trusted for
> reads, writes or both.
>
> Even more details (including register description) can be found
> in Chapter 4.7 AHB to IP Bridge (AIPSTZ)
> of i.MX8M Plus Application Processor Reference Manual.
>
> Signed-off-by: Daniel Baluta <daniel.baluta@xxxxxxx>
> ---
>
> This RFC patch is to get your opinion on the direction on how should
> we proceed with handling configuration registers for this kind of
> device.
>
> It registers itself as a platform driver at boot time and then is probed
> once the dts node is discovered.
>
> TBD:
> - device tree binding file
> - enhance error checking
> - is this the correct way to handle this kind of "peripheral".
>
> arch/arm64/boot/dts/freescale/imx8mp.dtsi | 7 ++
> drivers/soc/imx/aipstz.c | 114 ++++++++++++++++++++++
> 2 files changed, 121 insertions(+)
> create mode 100644 drivers/soc/imx/aipstz.c
>
> diff --git a/arch/arm64/boot/dts/freescale/imx8mp.dtsi b/arch/arm64/boot/dts/freescale/imx8mp.dtsi
> index e0d3b8cba221..7775f5f58036 100644
> --- a/arch/arm64/boot/dts/freescale/imx8mp.dtsi
> +++ b/arch/arm64/boot/dts/freescale/imx8mp.dtsi
> @@ -1406,6 +1406,13 @@ aips5: bus@30c00000 {
> #size-cells = <1>;
> ranges;
>
> + aipstz5: bridge@30df0000 {
> + compatible = "fsl,imx8mp-aipstz";
> + reg = <0x30df0000 0x10000>;
> + power-domains = <&pgc_audio>;
> + status = "okay";
> + };
supposed
bridge@30df0000 {
...
some child node {
}
so child node's devies suspend/resume will after bidged's
suspend resume.
}
> +
> spba-bus@30c00000 {
> compatible = "fsl,spba-bus", "simple-bus";
> reg = <0x30c00000 0x100000>;
> diff --git a/drivers/soc/imx/aipstz.c b/drivers/soc/imx/aipstz.c
> new file mode 100644
> index 000000000000..49a619f17dda
> --- /dev/null
> +++ b/drivers/soc/imx/aipstz.c
> @@ -0,0 +1,114 @@
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/of.h>
> +#include <linux/pm_domain.h>
> +#include <linux/io.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +
> +#define DRV_NAME "aips-bridge"
> +
> +#define AIPSTZ_MPR0 0x0
> +#define AIPSTZ_MPR1 0x4
> +
> +#define AIPSTZ_OPACR_NUM (0x5)
> +#define OPACR_OFFSET(i) ((i) * 4 + 0x40)
> +
> +struct aipstz_drv {
> + void __iomem *base;
> + struct notifier_block power_nb;
> + struct aipstz_cfg *cfg;
> +};
> +
> +struct aipstz_cfg {
> + uint32_t mpr0;
> + uint32_t mpr1;
> + uint32_t opacr[AIPSTZ_OPACR_NUM];
> +};
> +
> +static struct aipstz_cfg aipstz5 = {
> + 0x77777777,
> + 0x77777777,
> + .opacr = {0x0, 0x0, 0x0, 0x0, 0x0}
> +};
> +
> +static void imx_aipstz_config_init(const struct aipstz_drv *drv)
> +
> +{
> + const struct aipstz_cfg *aipstz = drv->cfg;
> +
> + writel(aipstz->mpr0, drv->base + AIPSTZ_MPR0);
> + writel(aipstz->mpr1, drv->base + AIPSTZ_MPR1);
> +
> + for (int i = 0; i < AIPSTZ_OPACR_NUM; i++)
> + writel(aipstz->opacr[i], drv->base + OPACR_OFFSET(i));
> +}
> +
> +static int aipstz_power_notifier(struct notifier_block *nb,
> + unsigned long action, void *data)
> +{
> + struct aipstz_drv *drv = container_of(nb, struct aipstz_drv, power_nb);
> +
> + if (action != GENPD_NOTIFY_ON)
> + return NOTIFY_OK;
> +
> + imx_aipstz_config_init(drv);
> +
> + return NOTIFY_OK;
> +}
> +
> +static int aipstz_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct aipstz_drv *drv;
> +
> + drv = devm_kzalloc(dev, sizeof(*drv), GFP_KERNEL);
> + if (!drv)
> + return -ENOMEM;
> +
> + drv->base = of_iomap(pdev->dev.of_node, 0);
> + drv->power_nb.notifier_call = aipstz_power_notifier;
> + drv->cfg = &aipstz5;
> +
> + imx_aipstz_config_init(drv);
> +
> + if (dev->pm_domain)
> + dev_pm_genpd_add_notifier(dev, &drv->power_nb);
> +
> + dev_set_drvdata(dev, drv);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id aipstz_of_match[] = {
> + {.compatible = "fsl,imx8mp-aipstz", },
> + {}
> +};
> +
> +static struct platform_driver aipstz_driver = {
> + .probe = aipstz_probe,
> + .driver = {
> + .name = DRV_NAME,
> + .of_match_table = of_match_ptr(aipstz_of_match),
> + },
> +};
> +
> +static int __init aipstz_driver_init(void)
> +{
> + int ret;
> +
> + ret = platform_driver_register(&aipstz_driver);
> + if (ret) {
> + pr_err("Failed to register aipstz platform driver\n");
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +device_initcall(aipstz_driver_init);
> +
> +MODULE_DESCRIPTION("i.MX8 AIPS bus configuration driver");
> +MODULE_AUTHOR("Daniel Baluta <daniel.baluta@xxxxxxx>");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:" DRV_NAME);
> --
> 2.43.0
>
