Re: [PATCH v5 4/8] memory: Add STM32 Octo Memory Manager driver

[Patrice CHOTARD]

On 2/19/25 09:00, patrice.chotard@xxxxxxxxxxx wrote:
> From: Patrice Chotard <patrice.chotard@xxxxxxxxxxx>
> 
> Octo Memory Manager driver (OMM) manages:
>   - the muxing between 2 OSPI busses and 2 output ports.
>     There are 4 possible muxing configurations:
>       - direct mode (no multiplexing): OSPI1 output is on port 1 and OSPI2
>         output is on port 2
>       - OSPI1 and OSPI2 are multiplexed over the same output port 1
>       - swapped mode (no multiplexing), OSPI1 output is on port 2,
>         OSPI2 output is on port 1
>       - OSPI1 and OSPI2 are multiplexed over the same output port 2
>   - the split of the memory area shared between the 2 OSPI instances.
>   - chip select selection override.
>   - the time between 2 transactions in multiplexed mode.
>   - check firewall access.
> 
> Signed-off-by: Patrice Chotard <patrice.chotard@xxxxxxxxxxx>
> Signed-off-by: Christophe Kerello <christophe.kerello@xxxxxxxxxxx>
> ---
>  drivers/memory/Kconfig     |  17 ++
>  drivers/memory/Makefile    |   1 +
>  drivers/memory/stm32_omm.c | 522 +++++++++++++++++++++++++++++++++++++
>  3 files changed, 540 insertions(+)
>  create mode 100644 drivers/memory/stm32_omm.c
> 
> diff --git a/drivers/memory/Kconfig b/drivers/memory/Kconfig
> index c82d8d8a16ea..3a0703fbfee7 100644
> --- a/drivers/memory/Kconfig
> +++ b/drivers/memory/Kconfig
> @@ -225,6 +225,23 @@ config STM32_FMC2_EBI
>  	  devices (like SRAM, ethernet adapters, FPGAs, LCD displays, ...) on
>  	  SOCs containing the FMC2 External Bus Interface.
>  
> +config STM32_OMM
> +	tristate "STM32 Octo Memory Manager"
> +	depends on SPI_STM32_OSPI || COMPILE_TEST
> +	help
> +	  This driver manages the muxing between the 2 OSPI busses and
> +	  the 2 output ports. There are 4 possible muxing configurations:
> +	  - direct mode (no multiplexing): OSPI1 output is on port 1 and OSPI2
> +	       output is on port 2
> +	  - OSPI1 and OSPI2 are multiplexed over the same output port 1
> +	  - swapped mode (no multiplexing), OSPI1 output is on port 2,
> +	       OSPI2 output is on port 1
> +	  - OSPI1 and OSPI2 are multiplexed over the same output port 2
> +	  It also manages :
> +	    - the split of the memory area shared between the 2 OSPI instances.
> +	    - chip select selection override.
> +	    - the time between 2 transactions in multiplexed mode.
> +
>  source "drivers/memory/samsung/Kconfig"
>  source "drivers/memory/tegra/Kconfig"
>  
> diff --git a/drivers/memory/Makefile b/drivers/memory/Makefile
> index d2e6ca9abbe0..c1959661bf63 100644
> --- a/drivers/memory/Makefile
> +++ b/drivers/memory/Makefile
> @@ -24,6 +24,7 @@ obj-$(CONFIG_DA8XX_DDRCTL)	+= da8xx-ddrctl.o
>  obj-$(CONFIG_PL353_SMC)		+= pl353-smc.o
>  obj-$(CONFIG_RENESAS_RPCIF)	+= renesas-rpc-if.o
>  obj-$(CONFIG_STM32_FMC2_EBI)	+= stm32-fmc2-ebi.o
> +obj-$(CONFIG_STM32_OMM)		+= stm32_omm.o
>  
>  obj-$(CONFIG_SAMSUNG_MC)	+= samsung/
>  obj-$(CONFIG_TEGRA_MC)		+= tegra/
> diff --git a/drivers/memory/stm32_omm.c b/drivers/memory/stm32_omm.c
> new file mode 100644
> index 000000000000..8f7f475769e7
> --- /dev/null
> +++ b/drivers/memory/stm32_omm.c
> @@ -0,0 +1,522 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) STMicroelectronics 2025 - All Rights Reserved
> + * Author(s): Patrice Chotard <patrice.chotard@xxxxxxxxxxx> for STMicroelectronics.
> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/bus/stm32_firewall_device.h>
> +#include <linux/clk.h>
> +#include <linux/err.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/of_platform.h>
> +#include <linux/pinctrl/consumer.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/regmap.h>
> +#include <linux/reset.h>
> +
> +#define OMM_CR			0
> +#define CR_MUXEN		BIT(0)
> +#define CR_MUXENMODE_MASK	GENMASK(1, 0)
> +#define CR_CSSEL_OVR_EN		BIT(4)
> +#define CR_CSSEL_OVR_MASK	GENMASK(6, 5)
> +#define CR_REQ2ACK_MASK		GENMASK(23, 16)
> +
> +#define OMM_CHILD_NB		2
> +
> +struct ospi_child {
> +	struct device *dev;
> +	struct device_node *node;
> +	struct clk *clk;
> +};
> +
> +struct stm32_omm {
> +	struct ospi_child child[OMM_CHILD_NB];
> +	struct resource *mm_res;
> +	struct clk *clk;
> +	void __iomem *io_base;
> +	u32 cr;
> +	u8 nb_child;
> +	bool restore_omm;
> +};
> +
> +static int stm32_omm_set_amcr(struct device *dev, bool set)
> +{
> +	struct stm32_omm *omm = dev_get_drvdata(dev);
> +	struct regmap *syscfg_regmap;
> +	struct device_node *node;
> +	struct resource res, res1;
> +	resource_size_t mm_ospi2_size = 0;
> +	static const char * const mm_name[] = { "ospi1", "ospi2" };
> +	u32 amcr_base, amcr_mask;
> +	int ret, idx;
> +	unsigned int i, amcr, read_amcr;
> +
> +	for (i = 0; i < omm->nb_child; i++) {
> +		idx = of_property_match_string(dev->of_node,
> +					       "memory-region-names",
> +					       mm_name[i]);
> +		if (idx < 0)
> +			continue;
> +
> +		/* res1 only used on second loop iteration */
> +		res1.start = res.start;
> +		res1.end = res.end;
> +
> +		node = of_parse_phandle(dev->of_node, "memory-region", idx);
> +		if (!node)
> +			continue;
> +
> +		ret = of_address_to_resource(node, 0, &res);
> +		if (ret) {
> +			dev_err(dev, "unable to resolve memory region\n");
> +			return ret;
> +		}
> +
> +		/* check that memory region fits inside OMM memory map area */
> +		if (!resource_contains(omm->mm_res, &res)) {
> +			dev_err(dev, "%s doesn't fit inside OMM memory map area\n",
> +				mm_name[i]);
> +			dev_err(dev, "%pR doesn't fit inside %pR\n", &res, omm->mm_res);
> +
> +			return -EFAULT;
> +		}
> +
> +		if (i == 1) {
> +			mm_ospi2_size = resource_size(&res);
> +
> +			/* check that OMM memory region 1 doesn't overlap memory region 2 */
> +			if (resource_overlaps(&res, &res1)) {
> +				dev_err(dev, "OMM memory-region %s overlaps memory region %s\n",
> +					mm_name[0], mm_name[1]);
> +				dev_err(dev, "%pR overlaps %pR\n", &res1, &res);
> +
> +				return -EFAULT;
> +			}
> +		}
> +	}
> +
> +	syscfg_regmap = syscon_regmap_lookup_by_phandle(dev->of_node, "st,syscfg-amcr");
> +	if (IS_ERR(syscfg_regmap)) {
> +		dev_err(dev, "Failed to get st,syscfg-amcr property\n");
> +		return PTR_ERR(syscfg_regmap);
> +	}
> +
> +	ret = of_property_read_u32_index(dev->of_node, "st,syscfg-amcr", 1,
> +					 &amcr_base);
> +	if (ret)
> +		return ret;
> +
> +	ret = of_property_read_u32_index(dev->of_node, "st,syscfg-amcr", 2,
> +					 &amcr_mask);
> +	if (ret)
> +		return ret;
> +
> +	amcr = mm_ospi2_size / SZ_64M;
> +
> +	if (set)
> +		regmap_update_bits(syscfg_regmap, amcr_base, amcr_mask, amcr);
> +
> +	/* read AMCR and check coherency with memory-map areas defined in DT */
> +	regmap_read(syscfg_regmap, amcr_base, &read_amcr);
> +	read_amcr = read_amcr >> (ffs(amcr_mask) - 1);
> +
> +	if (amcr != read_amcr) {
> +		dev_err(dev, "AMCR value not coherent with DT memory-map areas\n");
> +		ret = -EINVAL;
> +	}
> +
> +	return ret;
> +}
> +
> +static int stm32_omm_enable_child_clock(struct device *dev, bool enable)
> +{
> +	/* As there is only 2 children, remember first child in case of error */
> +	struct clk *first_child_clk = NULL;
> +	struct stm32_omm *omm = dev_get_drvdata(dev);
> +	u8 i;
> +	int ret;
> +
> +	for (i = 0; i < omm->nb_child; i++) {
> +		if (enable) {
> +			ret = clk_prepare_enable(omm->child[i].clk);
> +			if (ret) {
> +				if (first_child_clk)
> +					clk_disable_unprepare(first_child_clk);
> +
> +				dev_err(dev, "Can not enable clock\n");
> +				return ret;
> +			}
> +		} else {
> +			clk_disable_unprepare(omm->child[i].clk);
> +		}
> +
> +		first_child_clk = omm->child[i].clk;
> +	}
> +
> +	return 0;
> +}
> +
> +static int stm32_omm_configure(struct device *dev)
> +{
> +	struct stm32_omm *omm = dev_get_drvdata(dev);
> +	struct reset_control *rstc;
> +	unsigned long clk_rate, clk_rate_max = 0;
> +	int ret;
> +	u8 i;
> +	u32 mux = 0;
> +	u32 cssel_ovr = 0;
> +	u32 req2ack = 0;
> +
> +	omm->clk = devm_clk_get(dev, NULL);
> +	if (IS_ERR(omm->clk)) {
> +		dev_err(dev, "Failed to get OMM clock (%ld)\n",
> +			PTR_ERR(omm->clk));
> +
> +		return PTR_ERR(omm->clk);
> +	}
> +
> +	ret = pm_runtime_resume_and_get(dev);
> +	if (ret < 0)
> +		return ret;
> +
> +	/* parse children's clock */
> +	for (i = 0; i < omm->nb_child; i++) {
> +		clk_rate = clk_get_rate(omm->child[i].clk);
> +		if (!clk_rate) {
> +			dev_err(dev, "Invalid clock rate\n");
> +			pm_runtime_disable(dev);
> +			goto err_clk_disable;
> +		}
> +
> +		if (clk_rate > clk_rate_max)
> +			clk_rate_max = clk_rate;
> +	}
> +
> +	rstc = devm_reset_control_get_optional_exclusive(dev, NULL);
> +	if (IS_ERR(rstc)) {
> +		ret = dev_err_probe(dev, PTR_ERR(rstc), "reset get failed\n");
> +		pm_runtime_disable(dev);
> +		goto err_clk_disable;
> +	}
> +
> +	reset_control_assert(rstc);
> +	udelay(2);
> +	reset_control_deassert(rstc);
> +
> +	omm->cr = readl_relaxed(omm->io_base + OMM_CR);
> +	/* optional */
> +	ret = of_property_read_u32(dev->of_node, "st,omm-mux", &mux);
> +	if (!ret) {
> +		if (mux & CR_MUXEN) {
> +			ret = of_property_read_u32(dev->of_node, "st,omm-req2ack-ns",
> +						   &req2ack);
> +			if (!ret && !req2ack) {
> +				req2ack = DIV_ROUND_UP(req2ack, NSEC_PER_SEC / clk_rate_max) - 1;
> +
> +				if (req2ack > 256)
> +					req2ack = 256;
> +			}
> +
> +			req2ack = FIELD_PREP(CR_REQ2ACK_MASK, req2ack);
> +
> +			omm->cr &= ~CR_REQ2ACK_MASK;
> +			omm->cr |= FIELD_PREP(CR_REQ2ACK_MASK, req2ack);
> +
> +			/*
> +			 * If the mux is enabled, the 2 OSPI clocks have to be
> +			 * always enabled
> +			 */
> +			ret = stm32_omm_enable_child_clock(dev, true);
> +			if (ret) {
> +				pm_runtime_disable(dev);
> +				goto err_clk_disable;
> +			}
> +		}
> +
> +		omm->cr &= ~CR_MUXENMODE_MASK;
> +		omm->cr |= FIELD_PREP(CR_MUXENMODE_MASK, mux);
> +	}
> +
> +	/* optional */
> +	ret = of_property_read_u32(dev->of_node, "st,omm-cssel-ovr", &cssel_ovr);
> +	if (!ret) {
> +		omm->cr &= ~CR_CSSEL_OVR_MASK;
> +		omm->cr |= FIELD_PREP(CR_CSSEL_OVR_MASK, cssel_ovr);
> +		omm->cr |= CR_CSSEL_OVR_EN;
> +	}
> +
> +	omm->restore_omm = true;
> +	writel_relaxed(omm->cr, omm->io_base + OMM_CR);
> +
> +	ret = stm32_omm_set_amcr(dev, true);
> +
> +err_clk_disable:
> +	pm_runtime_put_sync_suspend(dev);
> +
> +	return ret;
> +}
> +
> +static int stm32_omm_check_access(struct device *dev, struct device_node *np)
> +{
> +	struct stm32_firewall firewall;
> +	int ret;
> +
> +	ret = stm32_firewall_get_firewall(np, &firewall, 1);
> +	if (ret)
> +		return ret;
> +
> +	return stm32_firewall_grant_access(&firewall);
> +}
> +
> +static int stm32_omm_disable_child(struct device *dev)
> +{
> +	struct stm32_omm *omm = dev_get_drvdata(dev);
> +	struct reset_control *reset;
> +	int ret;
> +	u8 i;
> +
> +	for (i = 0; i < omm->nb_child; i++) {
> +		ret = clk_prepare_enable(omm->child[i].clk);
> +		if (ret) {
> +			dev_err(dev, "Can not enable clock\n");
> +			return ret;
> +		}
> +
> +		reset = of_reset_control_get_exclusive(omm->child[i].node, 0);
> +		if (IS_ERR(reset)) {
> +			dev_err(dev, "Can't get child reset\n");
> +			return PTR_ERR(reset);
> +		};
> +
> +		/* reset OSPI to ensure CR_EN bit is set to 0 */
> +		reset_control_assert(reset);
> +		udelay(2);
> +		reset_control_deassert(reset);
> +
> +		reset_control_put(reset);
> +		clk_disable_unprepare(omm->child[i].clk);
> +	}
> +
> +	return 0;
> +}
> +
> +static int stm32_omm_probe(struct platform_device *pdev)
> +{
> +	struct platform_device *vdev;
> +	struct device *dev = &pdev->dev;
> +	struct stm32_omm *omm;
> +	struct clk *clk;
> +	int ret;
> +	u8 child_access_granted = 0;
> +	u8 i, j;
> +	bool child_access[OMM_CHILD_NB];
> +
> +	omm = devm_kzalloc(dev, sizeof(*omm), GFP_KERNEL);
> +	if (!omm)
> +		return -ENOMEM;
> +
> +	omm->io_base = devm_platform_ioremap_resource_byname(pdev, "regs");
> +	if (IS_ERR(omm->io_base))
> +		return PTR_ERR(omm->io_base);
> +
> +	omm->mm_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "memory_map");
> +	if (IS_ERR(omm->mm_res))
> +		return PTR_ERR(omm->mm_res);
> +
> +	/* check child's access */
> +	for_each_child_of_node_scoped(dev->of_node, child) {
> +		if (omm->nb_child >= OMM_CHILD_NB) {
> +			dev_err(dev, "Bad DT, found too much children\n");
> +			ret = -E2BIG;
> +			goto err_clk_release;
> +		}
> +
> +		if (!of_device_is_compatible(child, "st,stm32mp25-ospi")) {
> +			ret = -EINVAL;
> +			goto err_clk_release;
> +		}
> +
> +		ret = stm32_omm_check_access(dev, child);
> +		if (ret < 0 && ret != -EACCES)
> +			goto err_clk_release;
> +
> +		child_access[omm->nb_child] = false;
> +		if (!ret) {
> +			child_access_granted++;
> +			child_access[omm->nb_child] = true;
> +		}
> +
> +		omm->child[omm->nb_child].node = child;
> +
> +		clk = of_clk_get(child, 0);
> +		if (IS_ERR(clk)) {
> +			dev_err(dev, "Can't get child clock\n");
> +			ret = PTR_ERR(clk);
> +			goto err_clk_release;
> +		};
> +
> +		omm->child[omm->nb_child].clk = clk;
> +		omm->nb_child++;
> +	}
> +
> +	if (omm->nb_child != OMM_CHILD_NB) {
> +		ret = -EINVAL;
> +		goto err_clk_release;
> +	}
> +
> +	platform_set_drvdata(pdev, omm);
> +
> +	pm_runtime_enable(dev);
> +
> +	/* check if OMM's resource access is granted */
> +	ret = stm32_omm_check_access(dev, dev->of_node);
> +	if (ret < 0 && ret != -EACCES)
> +		goto err_clk_release;
> +
> +	if (!ret && child_access_granted == OMM_CHILD_NB) {
> +		/* Ensure both OSPI instance are disabled before configuring OMM */
> +		ret = stm32_omm_disable_child(dev);
> +		if (ret)
> +			goto err_clk_release;
> +
> +		ret = stm32_omm_configure(dev);
> +		if (ret)
> +			goto err_clk_release;
> +	} else {
> +		dev_dbg(dev, "Octo Memory Manager resource's access not granted\n");
> +		/*
> +		 * AMCR can't be set, so check if current value is coherent
> +		 * with memory-map areas defined in DT
> +		 */
> +		ret = stm32_omm_set_amcr(dev, false);
> +		if (ret)
> +			goto err_clk_release;
> +	}
> +
> +	/* for each child, if resource access is granted and status "okay", probe it */
> +	for (i = 0; i < omm->nb_child; i++) {
> +		if (!child_access[i] || !of_device_is_available(omm->child[i].node))
> +			continue;
> +
> +		vdev = of_platform_device_create(omm->child[i].node, NULL, NULL);
> +		if (!vdev) {
> +			dev_err(dev, "Failed to create Octo Memory Manager child\n");
> +			for (j = i; j > 0; --j) {
> +				if (omm->child[j].dev)
> +					of_platform_device_destroy(omm->child[j].dev, NULL);
> +			}
> +
> +			ret = -EINVAL;
> +			goto err_clk_release;
> +		}
> +		omm->child[i].dev = &vdev->dev;
> +	}
> +
> +err_clk_release:
> +	for (i = 0; i < omm->nb_child; i++)
> +		clk_put(omm->child[i].clk);
> +
> +	return ret;
> +}
> +
> +static void stm32_omm_remove(struct platform_device *pdev)
> +{
> +	struct stm32_omm *omm = platform_get_drvdata(pdev);
> +	int i;
> +
> +	for (i = 0; i < omm->nb_child; i++)
> +		if (omm->child[i].dev)
> +			of_platform_device_destroy(omm->child[i].dev, NULL);
> +
> +	if (omm->cr & CR_MUXEN)
> +		stm32_omm_enable_child_clock(&pdev->dev, false);
> +
> +	pm_runtime_disable(&pdev->dev);
> +}
> +
> +static const struct of_device_id stm32_omm_of_match[] = {
> +	{ .compatible = "st,stm32mp25-omm", },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, stm32_omm_of_match);
> +
> +static int __maybe_unused stm32_omm_runtime_suspend(struct device *dev)
> +{
> +	struct stm32_omm *omm = dev_get_drvdata(dev);
> +
> +	clk_disable_unprepare(omm->clk);
> +
> +	return 0;
> +}
> +
> +static int __maybe_unused stm32_omm_runtime_resume(struct device *dev)
> +{
> +	struct stm32_omm *omm = dev_get_drvdata(dev);
> +
> +	return clk_prepare_enable(omm->clk);
> +}
> +
> +static int __maybe_unused stm32_omm_suspend(struct device *dev)
> +{
> +	struct stm32_omm *omm = dev_get_drvdata(dev);
> +
> +	if (omm->restore_omm && omm->cr & CR_MUXEN)
> +		stm32_omm_enable_child_clock(dev, false);
> +
> +	return pinctrl_pm_select_sleep_state(dev);
> +}
> +
> +static int __maybe_unused stm32_omm_resume(struct device *dev)
> +{
> +	struct stm32_omm *omm = dev_get_drvdata(dev);
> +	int ret;
> +
> +	pinctrl_pm_select_default_state(dev);
> +
> +	if (!omm->restore_omm)
> +		return 0;
> +
> +	/* Ensure both OSPI instance are disabled before configuring OMM */
> +	ret = stm32_omm_disable_child(dev);
> +	if (ret)
> +		return ret;
> +
> +	ret = pm_runtime_resume_and_get(dev);
> +	if (ret < 0)
> +		return ret;
> +
> +	writel_relaxed(omm->cr, omm->io_base + OMM_CR);
> +	ret = stm32_omm_set_amcr(dev, true);
> +	pm_runtime_put_sync_suspend(dev);
> +	if (ret)
> +		return ret;
> +
> +	if (omm->cr & CR_MUXEN)
> +		ret = stm32_omm_enable_child_clock(dev, true);
> +
> +	return ret;
> +}
> +
> +static const struct dev_pm_ops stm32_omm_pm_ops = {
> +	SET_RUNTIME_PM_OPS(stm32_omm_runtime_suspend,
> +			   stm32_omm_runtime_resume, NULL)
> +	SET_SYSTEM_SLEEP_PM_OPS(stm32_omm_suspend, stm32_omm_resume)
> +};
> +
> +static struct platform_driver stm32_omm_driver = {
> +	.probe	= stm32_omm_probe,
> +	.remove = stm32_omm_remove,
> +	.driver	= {
> +		.name = "stm32-omm",
> +		.of_match_table = stm32_omm_of_match,
> +		.pm = &stm32_omm_pm_ops,
> +	},
> +};
> +module_platform_driver(stm32_omm_driver);
> +
> +MODULE_DESCRIPTION("STMicroelectronics Octo Memory Manager driver");
> +MODULE_LICENSE("GPL");


Hi all,

Anybody alse has additionnal remarks on this driver ?

Thanks
Patrice