On 11/10/2021 18:57, Hector Martin wrote:
> This driver binds to the memory controller hardware in Apple SoCs such
> as the Apple M1, and provides a power domain that downstream devices can
> use to change the performance state of the memory controller.
>
> Signed-off-by: Hector Martin <marcan@xxxxxxxxx>
> ---
> drivers/memory/Kconfig | 9 +++
> drivers/memory/Makefile | 1 +
> drivers/memory/apple-mcc.c | 130 +++++++++++++++++++++++++++++++++++++
> 3 files changed, 140 insertions(+)
> create mode 100644 drivers/memory/apple-mcc.c
>
> diff --git a/drivers/memory/Kconfig b/drivers/memory/Kconfig
> index 72c0df129d5c..48ef3d563a1c 100644
> --- a/drivers/memory/Kconfig
> +++ b/drivers/memory/Kconfig
> @@ -30,6 +30,15 @@ config ARM_PL172_MPMC
> If you have an embedded system with an AMBA bus and a PL172
> controller, say Y or M here.
>
> +config APPLE_MCC
> + tristate "Apple SoC MCC driver"
> + default y if ARCH_APPLE
> + select PM_GENERIC_DOMAINS
> + depends on ARCH_APPLE || COMPILE_TEST
> + help
> + This driver manages performance tuning for the memory controller in
> + Apple SoCs, such as the Apple M1.
> +
> config ATMEL_SDRAMC
> bool "Atmel (Multi-port DDR-)SDRAM Controller"
> default y if ARCH_AT91
> diff --git a/drivers/memory/Makefile b/drivers/memory/Makefile
> index bc7663ed1c25..947840cbd2d4 100644
> --- a/drivers/memory/Makefile
> +++ b/drivers/memory/Makefile
> @@ -8,6 +8,7 @@ ifeq ($(CONFIG_DDR),y)
> obj-$(CONFIG_OF) += of_memory.o
> endif
> obj-$(CONFIG_ARM_PL172_MPMC) += pl172.o
> +obj-$(CONFIG_APPLE_MCC) += apple-mcc.o
> obj-$(CONFIG_ATMEL_SDRAMC) += atmel-sdramc.o
> obj-$(CONFIG_ATMEL_EBI) += atmel-ebi.o
> obj-$(CONFIG_BRCMSTB_DPFE) += brcmstb_dpfe.o
> diff --git a/drivers/memory/apple-mcc.c b/drivers/memory/apple-mcc.c
> new file mode 100644
> index 000000000000..55959f034b9a
> --- /dev/null
> +++ b/drivers/memory/apple-mcc.c
> @@ -0,0 +1,130 @@
> +// SPDX-License-Identifier: GPL-2.0-only OR MIT
> +/*
> + * Apple SoC MCC memory controller performance control driver
> + *
> + * Copyright The Asahi Linux Contributors
Copyright date?
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_domain.h>
> +#include <linux/pm_opp.h>
> +
> +#define APPLE_MCC_PERF_CONFIG1 0xdc4
> +#define APPLE_MCC_PERF_CONFIG2 0xdbc
> +#define APPLE_MCC_CHANNEL(x) ((x) * 0x40000)
> +
> +struct apple_mcc {
> + struct device *dev;
> + struct generic_pm_domain genpd;
> + void __iomem *reg_base;
> + u32 num_channels;
> +};
> +
> +#define to_apple_mcc(_genpd) container_of(_genpd, struct apple_mcc, genpd)
> +
> +static int apple_mcc_set_performance_state(struct generic_pm_domain *genpd, unsigned int state)
> +{
> + struct apple_mcc *mcc = to_apple_mcc(genpd);
> + struct dev_pm_opp *opp;
> + struct device_node *np;
> + u32 perf_config[2];
> + unsigned int i;
> +
> + dev_dbg(mcc->dev, "switching to perf state %d\n", state);
> +
> + opp = dev_pm_opp_find_level_exact(&mcc->genpd.dev, state);
> + if (IS_ERR(opp))
> + return PTR_ERR(opp);
> +
> + np = dev_pm_opp_get_of_node(opp);
> + if (of_property_read_u32_array(np, "apple,memory-perf-config",
> + perf_config, ARRAY_SIZE(perf_config))) {
> + dev_err(mcc->dev, "missing apple,memory-perf-config property");
> + of_node_put(np);
> + return -EINVAL;
> + }
> + of_node_put(np);
> +
> + for (i = 0; i < mcc->num_channels; i++) {
> + writel_relaxed(perf_config[0],
> + mcc->reg_base + APPLE_MCC_CHANNEL(i) + APPLE_MCC_PERF_CONFIG1);
> + writel_relaxed(perf_config[1],
> + mcc->reg_base + APPLE_MCC_CHANNEL(i) + APPLE_MCC_PERF_CONFIG2);
> + }
> +
> + return 0;
> +}
> +
> +static unsigned int apple_mcc_opp_to_performance_state(struct generic_pm_domain *genpd,
> + struct dev_pm_opp *opp)
> +{
> + return dev_pm_opp_get_level(opp);
> +}
> +
> +static int apple_mcc_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct device_node *node = dev->of_node;
By convention mostly we call the variable "np".
> + struct apple_mcc *mcc;
> + int ret;
> +
> + mcc = devm_kzalloc(dev, sizeof(*mcc), GFP_KERNEL);
> + if (!mcc)
> + return -ENOMEM;
> +
> + mcc->reg_base = devm_platform_ioremap_resource(pdev, 0);
> + if (IS_ERR(mcc->reg_base))
> + return PTR_ERR(mcc->reg_base);
> +
> + if (of_property_read_u32(node, "apple,num-channels", &mcc->num_channels)) {
Don't you have a limit of supported channels? It cannot be any uint32...
> + dev_err(dev, "missing apple,num-channels property\n");
Use almost everywhere dev_err_probe - less code and you get error msg
printed.
> + return -ENOENT;
> + }
> +
> + mcc->dev = dev;
> + mcc->genpd.name = "apple-mcc-perf";
> + mcc->genpd.opp_to_performance_state = apple_mcc_opp_to_performance_state;
> + mcc->genpd.set_performance_state = apple_mcc_set_performance_state;
> +
> + ret = pm_genpd_init(&mcc->genpd, NULL, false);
> + if (ret < 0) {
> + dev_err(dev, "pm_genpd_init failed\n");
> + return ret;
> + }
> +
> + ret = of_genpd_add_provider_simple_noclk(node, &mcc->genpd);
> + if (ret < 0) {
> + dev_err(dev, "of_genpd_add_provider_simple failed\n");
> + return ret;
> + }
> +
> + dev_info(dev, "Apple MCC performance driver initialized\n");
Please skip it, or at least make it a dev_dbg, you don't print any
valuable information here.
> +
> + return 0;
> +}
> +
> +static const struct of_device_id apple_mcc_of_match[] = {
> + { .compatible = "apple,mcc" },
> + {}
> +};
> +
> +MODULE_DEVICE_TABLE(of, apple_mcc_of_match);
> +
> +static struct platform_driver apple_mcc_driver = {
> + .probe = apple_mcc_probe,
> + .driver = {
> + .name = "apple-mcc",
> + .of_match_table = apple_mcc_of_match,
> + },
> +};
module_platform_driver() goes here.
> +
> +MODULE_AUTHOR("Hector Martin <marcan@xxxxxxxxx>");
> +MODULE_DESCRIPTION("MCC memory controller performance tuning driver for Apple SoCs");
> +MODULE_LICENSE("GPL v2");
I think this will be "Dual MIT/GPL", based on your SPDX.
> +
> +module_platform_driver(apple_mcc_driver);
>
Best regards,
Krzysztof
