On 06.09.21 20:43, Lucas Stach wrote:
> This adds a driver for the blk-ctrl blocks found in the i.MX8M* line of
> SoCs. The blk-ctrl is a top-level peripheral located in the various *MIX
> power domains and interacts with the GPC power controller to provide the
> peripherals in the power domain access to the NoC and ensures that those
> peripherals are properly reset when their respective power domain is
> brought back to life.
>
> Software needs to do different things to make the bus handshake happen
> after the the GPC *MIX domain is power up and before it is powered down.
^ double "the" ^ powered
> As the requirements are quite different between the various blk-ctrls
> there is a callback function provided to hook in the proper sequence.
>
> The peripheral domains are quite uniform, they handle the soft clock
> enables and resets in the blk-ctrl address space and sequencing with the
> upstream GPC power domains.
>
> Signed-off-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
I don't understand all of the logic behind this implementation, but
looking at the code I don't see any obvious problems. So FWIW:
Acked-by: Frieder Schrempf <frieder.schrempf@xxxxxxxxxx>
> ---
> This commit includes the full code to drive the VPUMIX domain on the
> i.MX8MM, as the skeleton driver would probably be harder to review
> without the context provided by one blk-ctrl implementation. Other
> blk-ctrl implementations will follow, based on this overall structure.
> ---
> drivers/soc/imx/Makefile | 1 +
> drivers/soc/imx/imx8m-blk-ctrl.c | 455 +++++++++++++++++++++++++++++++
> 2 files changed, 456 insertions(+)
> create mode 100644 drivers/soc/imx/imx8m-blk-ctrl.c
>
> diff --git a/drivers/soc/imx/Makefile b/drivers/soc/imx/Makefile
> index 078dc918f4f3..8a707077914c 100644
> --- a/drivers/soc/imx/Makefile
> +++ b/drivers/soc/imx/Makefile
> @@ -5,3 +5,4 @@ endif
> obj-$(CONFIG_HAVE_IMX_GPC) += gpc.o
> obj-$(CONFIG_IMX_GPCV2_PM_DOMAINS) += gpcv2.o
> obj-$(CONFIG_SOC_IMX8M) += soc-imx8m.o
> +obj-$(CONFIG_SOC_IMX8M) += imx8m-blk-ctrl.o
> diff --git a/drivers/soc/imx/imx8m-blk-ctrl.c b/drivers/soc/imx/imx8m-blk-ctrl.c
> new file mode 100644
> index 000000000000..3dd17b903636
> --- /dev/null
> +++ b/drivers/soc/imx/imx8m-blk-ctrl.c
> @@ -0,0 +1,455 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +
> +/*
> + * Copyright 2021 Pengutronix, Lucas Stach <kernel@xxxxxxxxxxxxxx>
> + */
> +
> +#include <linux/device.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_domain.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/regmap.h>
> +#include <linux/clk.h>
> +
> +#include <dt-bindings/power/imx8mm-power.h>
> +
> +#define BLK_SFT_RSTN 0x0
> +#define BLK_CLK_EN 0x4
> +
> +struct imx8m_blk_ctrl_domain;
> +
> +struct imx8m_blk_ctrl {
> + struct device *dev;
> + struct notifier_block power_nb;
> + struct device *bus_power_dev;
> + struct regmap *regmap;
> + struct imx8m_blk_ctrl_domain *domains;
> + struct genpd_onecell_data onecell_data;
> +};
> +
> +struct imx8m_blk_ctrl_domain_data {
> + const char *name;
> + const char **clk_names;
> + int num_clks;
> + const char *gpc_name;
> + u32 rst_mask;
> + u32 clk_mask;
> +};
> +
> +#define DOMAIN_MAX_CLKS 3
> +
> +struct imx8m_blk_ctrl_domain {
> + struct generic_pm_domain genpd;
> + const struct imx8m_blk_ctrl_domain_data *data;
> + struct clk_bulk_data clks[DOMAIN_MAX_CLKS];
> + struct device *power_dev;
> + struct imx8m_blk_ctrl *bc;
> +};
> +
> +struct imx8m_blk_ctrl_data {
> + int max_reg;
> + notifier_fn_t power_notifier_fn;
> + const struct imx8m_blk_ctrl_domain_data *domains;
> + int num_domains;
> +};
> +
> +static inline struct imx8m_blk_ctrl_domain *
> +to_imx8m_blk_ctrl_domain(struct generic_pm_domain *genpd)
> +{
> + return container_of(genpd, struct imx8m_blk_ctrl_domain, genpd);
> +}
> +
> +static int imx8m_blk_ctrl_power_on(struct generic_pm_domain *genpd)
> +{
> + struct imx8m_blk_ctrl_domain *domain = to_imx8m_blk_ctrl_domain(genpd);
> + const struct imx8m_blk_ctrl_domain_data *data = domain->data;
> + struct imx8m_blk_ctrl *bc = domain->bc;
> + int ret;
> +
> + /* make sure bus domain is awake */
> + ret = pm_runtime_get_sync(bc->bus_power_dev);
> + if (ret < 0) {
> + pm_runtime_put_noidle(bc->bus_power_dev);
> + dev_err(bc->dev, "failed to power up bus domain\n");
> + return ret;
> + }
> +
> + /* put devices into reset */
> + regmap_clear_bits(bc->regmap, BLK_SFT_RSTN, data->rst_mask);
> +
> + /* enable upstream and blk-ctrl clocks to allow reset to propagate */
> + ret = clk_bulk_prepare_enable(data->num_clks, domain->clks);
> + if (ret) {
> + dev_err(bc->dev, "failed to enable clocks\n");
> + goto bus_put;
> + }
> + regmap_set_bits(bc->regmap, BLK_CLK_EN, data->clk_mask);
> +
> + /* power up upstream GPC domain */
> + ret = pm_runtime_get_sync(domain->power_dev);
> + if (ret < 0) {
> + dev_err(bc->dev, "failed to power up peripheral domain\n");
> + goto clk_disable;
> + }
> +
> + /* wait for reset to propagate */
> + udelay(5);
> +
> + /* release reset */
> + regmap_set_bits(bc->regmap, BLK_SFT_RSTN, data->rst_mask);
> +
> + /* disable upstream clocks */
> + clk_bulk_disable_unprepare(data->num_clks, domain->clks);
> +
> + return 0;
> +
> +clk_disable:
> + clk_bulk_disable_unprepare(data->num_clks, domain->clks);
> +bus_put:
> + pm_runtime_put(bc->bus_power_dev);
> +
> + return ret;
> +}
> +
> +static int imx8m_blk_ctrl_power_off(struct generic_pm_domain *genpd)
> +{
> + struct imx8m_blk_ctrl_domain *domain = to_imx8m_blk_ctrl_domain(genpd);
> + const struct imx8m_blk_ctrl_domain_data *data = domain->data;
> + struct imx8m_blk_ctrl *bc = domain->bc;
> +
> + /* put devices into reset and disable clocks */
> + regmap_clear_bits(bc->regmap, BLK_SFT_RSTN, data->rst_mask);
> + regmap_clear_bits(bc->regmap, BLK_CLK_EN, data->clk_mask);
> +
> + /* power down upstream GPC domain */
> + pm_runtime_put(domain->power_dev);
> +
> + /* allow bus domain to suspend */
> + pm_runtime_put(bc->bus_power_dev);
> +
> + return 0;
> +}
> +
> +static struct generic_pm_domain *
> +imx8m_blk_ctrl_xlate(struct of_phandle_args *args, void *data)
> +{
> + struct genpd_onecell_data *onecell_data = data;
> + unsigned int index = args->args[0];
> +
> + if (args->args_count != 1 ||
> + index > onecell_data->num_domains)
> + return ERR_PTR(-EINVAL);
> +
> + return onecell_data->domains[index];
> +}
> +
> +static struct lock_class_key blk_ctrl_genpd_lock_class;
> +
> +static int imx8m_blk_ctrl_probe(struct platform_device *pdev)
> +{
> + const struct imx8m_blk_ctrl_data *bc_data;
> + struct device *dev = &pdev->dev;
> + struct imx8m_blk_ctrl *bc;
> + void __iomem *base;
> + int i, ret;
> +
> + struct regmap_config regmap_config = {
> + .reg_bits = 32,
> + .val_bits = 32,
> + .reg_stride = 4,
> + };
> +
> + bc = devm_kzalloc(dev, sizeof(*bc), GFP_KERNEL);
> + if (!bc)
> + return -ENOMEM;
> +
> + bc->dev = dev;
> +
> + bc_data = of_device_get_match_data(dev);
> +
> + base = devm_platform_ioremap_resource(pdev, 0);
> + if (IS_ERR(base))
> + return PTR_ERR(base);
> +
> + regmap_config.max_register = bc_data->max_reg;
> + bc->regmap = devm_regmap_init_mmio(dev, base, ®map_config);
> + if (IS_ERR(bc->regmap))
> + return dev_err_probe(dev, PTR_ERR(bc->regmap),
> + "failed to init regmap \n");
> +
> + bc->domains = devm_kcalloc(dev, bc_data->num_domains,
> + sizeof(struct imx8m_blk_ctrl_domain),
> + GFP_KERNEL);
> + if (!bc->domains)
> + return -ENOMEM;
> +
> + bc->onecell_data.num_domains = bc_data->num_domains;
> + bc->onecell_data.xlate = imx8m_blk_ctrl_xlate;
> + bc->onecell_data.domains =
> + devm_kcalloc(dev, bc_data->num_domains,
> + sizeof(struct generic_pm_domain *), GFP_KERNEL);
> + if (!bc->onecell_data.domains)
> + return -ENOMEM;
> +
> + bc->bus_power_dev = genpd_dev_pm_attach_by_name(dev, "bus");
> + if (IS_ERR(bc->bus_power_dev))
> + return dev_err_probe(dev, PTR_ERR(bc->bus_power_dev),
> + "failed to attach power domain\n");
> +
> + for (i = 0; i < bc_data->num_domains; i++) {
> + const struct imx8m_blk_ctrl_domain_data *data = &bc_data->domains[i];
> + struct imx8m_blk_ctrl_domain *domain = &bc->domains[i];
> + int j;
> +
> + domain->data = data;
> +
> + for (j = 0; j < data->num_clks; j++)
> + domain->clks[j].id = data->clk_names[j];
> +
> + ret = devm_clk_bulk_get(dev, data->num_clks, domain->clks);
> + if (ret) {
> + dev_err_probe(dev, ret, "failed to get clock\n");
> + goto cleanup_pds;
> + }
> +
> + domain->power_dev =
> + dev_pm_domain_attach_by_name(dev, data->gpc_name);
> + if (IS_ERR(domain->power_dev)) {
> + dev_err_probe(dev, PTR_ERR(domain->power_dev),
> + "failed to attach power domain\n");
> + ret = PTR_ERR(domain->power_dev);
> + goto cleanup_pds;
> + }
> +
> + domain->genpd.name = data->name;
> + domain->genpd.power_on = imx8m_blk_ctrl_power_on;
> + domain->genpd.power_off = imx8m_blk_ctrl_power_off;
> + domain->bc = bc;
> +
> + ret = pm_genpd_init(&domain->genpd, NULL, true);
> + if (ret) {
> + dev_err_probe(dev, ret, "failed to init power domain\n");
> + dev_pm_domain_detach(domain->power_dev, true);
> + goto cleanup_pds;
> + }
> +
> + /*
> + * We use runtime PM to trigger power on/off of the upstream GPC
> + * domain, as a strict hierarchical parent/child power domain
> + * setup doesn't allow us to meet the sequencing requirements.
> + * This means we have nested locking of genpd locks, without the
> + * nesting being visible at the genpd level, so we need a
> + * separate lock class to make lockdep aware of the fact that
> + * this are separate domain locks that can be nested without a
> + * self-deadlock.
> + */
> + lockdep_set_class(&domain->genpd.mlock,
> + &blk_ctrl_genpd_lock_class);
> +
> + bc->onecell_data.domains[i] = &domain->genpd;
> + }
> +
> + ret = of_genpd_add_provider_onecell(dev->of_node, &bc->onecell_data);
> + if (ret) {
> + dev_err_probe(dev, ret, "failed to add power domain provider\n");
> + goto cleanup_pds;
> + }
> +
> + bc->power_nb.notifier_call = bc_data->power_notifier_fn;
> + ret = dev_pm_genpd_add_notifier(bc->bus_power_dev, &bc->power_nb);
> + if (ret) {
> + dev_err_probe(dev, ret, "failed to add power notifier\n");
> + goto cleanup_provider;
> + }
> +
> + dev_set_drvdata(dev, bc);
> +
> + return 0;
> +
> +cleanup_provider:
> + of_genpd_del_provider(dev->of_node);
> +cleanup_pds:
> + for (i--; i >= 0; i--) {
> + pm_genpd_remove(&bc->domains[i].genpd);
> + dev_pm_domain_detach(bc->domains[i].power_dev, true);
> + }
> +
> + dev_pm_domain_detach(bc->bus_power_dev, true);
> +
> + return ret;
> +}
> +
> +static int imx8m_blk_ctrl_remove(struct platform_device *pdev)
> +{
> + struct imx8m_blk_ctrl *bc = dev_get_drvdata(&pdev->dev);
> + int i;
> +
> + of_genpd_del_provider(pdev->dev.of_node);
> +
> + for (i = 0; bc->onecell_data.num_domains; i++) {
> + struct imx8m_blk_ctrl_domain *domain = &bc->domains[i];
> +
> + pm_genpd_remove(&domain->genpd);
> + dev_pm_domain_detach(domain->power_dev, true);
> + }
> +
> + dev_pm_genpd_remove_notifier(bc->bus_power_dev);
> +
> + dev_pm_domain_detach(bc->bus_power_dev, true);
> +
> + return 0;
> +}
> +
> +#ifdef CONFIG_PM_SLEEP
> +static int imx8m_blk_ctrl_suspend(struct device *dev)
> +{
> + struct imx8m_blk_ctrl *bc = dev_get_drvdata(dev);
> + int ret, i;
> +
> + /*
> + * This may look strange, but is done so the generic PM_SLEEP code
> + * can power down our domains and more importantly power them up again
> + * after resume, without tripping over our usage of runtime PM to
> + * control the upstream GPC domains. Things happen in the right order
> + * in the system suspend/resume paths due to the device parent/child
> + * hierarchy.
> + */
> + ret = pm_runtime_get_sync(bc->bus_power_dev);
> + if (ret < 0) {
> + pm_runtime_put_noidle(bc->bus_power_dev);
> + return ret;
> + }
> +
> + for (i = 0; i < bc->onecell_data.num_domains; i++) {
> + struct imx8m_blk_ctrl_domain *domain = &bc->domains[i];
> +
> + ret = pm_runtime_get_sync(domain->power_dev);
> + if (ret < 0) {
> + pm_runtime_put_noidle(domain->power_dev);
> + goto out_fail;
> + }
> + }
> +
> + return 0;
> +
> +out_fail:
> + for (i--; i >= 0; i--)
> + pm_runtime_put(bc->domains[i].power_dev);
> +
> + pm_runtime_put(bc->bus_power_dev);
> +
> + return ret;
> +}
> +
> +static int imx8m_blk_ctrl_resume(struct device *dev)
> +{
> + struct imx8m_blk_ctrl *bc = dev_get_drvdata(dev);
> + int i;
> +
> + for (i = 0; i < bc->onecell_data.num_domains; i++)
> + pm_runtime_put(bc->domains[i].power_dev);
> +
> + pm_runtime_put(bc->bus_power_dev);
> +
> + return 0;
> +}
> +#endif
> +
> +static const struct dev_pm_ops imx8m_blk_ctrl_pm_ops = {
> + SET_SYSTEM_SLEEP_PM_OPS(imx8m_blk_ctrl_suspend, imx8m_blk_ctrl_resume)
> +};
> +
> +static int imx8mm_vpu_power_notifier(struct notifier_block *nb,
> + unsigned long action, void *data)
> +{
> + struct imx8m_blk_ctrl *bc = container_of(nb, struct imx8m_blk_ctrl,
> + power_nb);
> +
> + if (action != GENPD_NOTIFY_ON && action != GENPD_NOTIFY_PRE_OFF)
> + return NOTIFY_OK;
> +
> + /*
> + * The ADB in the VPUMIX domain has no separate reset and clock
> + * enable bits, but is ungated together with the VPU clocks. To
> + * allow the handshake with the GPC to progress we put the VPUs
> + * in reset and ungate the clocks.
> + */
> + regmap_clear_bits(bc->regmap, BLK_SFT_RSTN,
> + BIT(0) | BIT(1) | BIT(2));
> + regmap_set_bits(bc->regmap, BLK_CLK_EN,
> + BIT(0) | BIT(1) | BIT(2));
> +
> + if (action == GENPD_NOTIFY_ON) {
> + /*
> + * On power up we have no software backchannel to the GPC to
> + * wait for the ADB handshake to happen, so we just delay for a
> + * bit. On power down the GPC driver waits for the handshake.
> + */
> + udelay(5);
> +
> + /* set "fuse" bits to enable the VPUs */
> + regmap_set_bits(bc->regmap, 0x8, 0xffffffff);
> + regmap_set_bits(bc->regmap, 0xc, 0xffffffff);
> + regmap_set_bits(bc->regmap, 0x10, 0xffffffff);
> + regmap_set_bits(bc->regmap, 0x14, 0xffffffff);
> + }
> +
> + return NOTIFY_OK;
> +}
> +
> +static const struct imx8m_blk_ctrl_domain_data imx8m_vpu_blk_ctl_domain_data[] = {
> + [IMX8MM_VPUBLK_PD_G1] = {
> + .name = "vpublk-g1",
> + .clk_names = (const char *[]){ "g1", },
> + .num_clks = 1,
> + .gpc_name = "g1",
> + .rst_mask = BIT(1),
> + .clk_mask = BIT(1),
> + },
> + [IMX8MM_VPUBLK_PD_G2] = {
> + .name = "vpublk-g2",
> + .clk_names = (const char *[]){ "g2", },
> + .num_clks = 1,
> + .gpc_name = "g2",
> + .rst_mask = BIT(0),
> + .clk_mask = BIT(0),
> + },
> + [IMX8MM_VPUBLK_PD_H1] = {
> + .name = "vpublk-h1",
> + .clk_names = (const char *[]){ "h1", },
> + .num_clks = 1,
> + .gpc_name = "h1",
> + .rst_mask = BIT(2),
> + .clk_mask = BIT(2),
> + },
> +};
> +
> +static const struct imx8m_blk_ctrl_data imx8m_vpu_blk_ctl_dev_data = {
> + .max_reg = 0x18,
> + .power_notifier_fn = imx8mm_vpu_power_notifier,
> + .domains = imx8m_vpu_blk_ctl_domain_data,
> + .num_domains = ARRAY_SIZE(imx8m_vpu_blk_ctl_domain_data),
> +};
> +
> +static const struct of_device_id imx8m_blk_ctrl_of_match[] = {
> + {
> + .compatible = "fsl,imx8mm-vpu-blk-ctrl",
> + .data = &imx8m_vpu_blk_ctl_dev_data
> + }, {
> + /* Sentinel */
> + }
> +};
> +MODULE_DEVICE_TABLE(of, imx8m_blk_ctrl_of_match);
> +
> +static struct platform_driver imx8m_blk_ctrl_driver = {
> + .probe = imx8m_blk_ctrl_probe,
> + .remove = imx8m_blk_ctrl_remove,
> + .driver = {
> + .name = "imx8m-blk-ctrl",
> + .pm = &imx8m_blk_ctrl_pm_ops,
> + .of_match_table = imx8m_blk_ctrl_of_match,
> + },
> +};
> +module_platform_driver(imx8m_blk_ctrl_driver);
>
