memory: Add STM32 Octo Memory Manager driver

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: Christophe Kerello <[e-mail]>
Signed-off-by: Patrice Chotard <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Krzysztof Kozlowski <[e-mail]>

drivers/memory/Kconfig

···
 	  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"
 

drivers/memory/Makefile

···
 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/

drivers/memory/stm32_omm.c

···
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) STMicroelectronics 2025 - All Rights Reserved
+ * Author(s): Patrice Chotard <[e-mail]> 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
+#define OMM_CLK_NB		3
+
+struct stm32_omm {
+	struct resource *mm_res;
+	struct clk_bulk_data clk_bulk[OMM_CLK_NB];
+	struct reset_control *child_reset[OMM_CHILD_NB];
+	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);
+	resource_size_t mm_ospi2_size = 0;
+	static const char * const mm_name[] = { "ospi1", "ospi2" };
+	struct regmap *syscfg_regmap;
+	struct device_node *node;
+	struct resource res, res1;
+	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) {
+			of_node_put(node);
+			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);
+			of_node_put(node);
+
+			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);
+				of_node_put(node);
+
+				return -EFAULT;
+			}
+		}
+		of_node_put(node);
+	}
+
+	syscfg_regmap = syscon_regmap_lookup_by_phandle(dev->of_node, "st,syscfg-amcr");
+	if (IS_ERR(syscfg_regmap))
+		return dev_err_probe(dev, PTR_ERR(syscfg_regmap),
+				     "Failed to get st,syscfg-amcr property\n");
+
+	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_toggle_child_clock(struct device *dev, bool enable)
+{
+	struct stm32_omm *omm = dev_get_drvdata(dev);
+	int i, ret;
+
+	for (i = 0; i < omm->nb_child; i++) {
+		if (enable) {
+			ret = clk_prepare_enable(omm->clk_bulk[i + 1].clk);
+			if (ret) {
+				dev_err(dev, "Can not enable clock\n");
+				goto clk_error;
+			}
+		} else {
+			clk_disable_unprepare(omm->clk_bulk[i + 1].clk);
+		}
+	}
+
+	return 0;
+
+clk_error:
+	while (i--)
+		clk_disable_unprepare(omm->clk_bulk[i + 1].clk);
+
+	return ret;
+}
+
+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;
+
+	ret = stm32_omm_toggle_child_clock(dev, true);
+	if (!ret)
+		return ret;
+
+	for (i = 0; i < omm->nb_child; i++) {
+		/* reset OSPI to ensure CR_EN bit is set to 0 */
+		reset = omm->child_reset[i];
+		ret = reset_control_acquire(reset);
+		if (ret) {
+			stm32_omm_toggle_child_clock(dev, false);
+			dev_err(dev, "Can not acquire resset %d\n", ret);
+			return ret;
+		}
+
+		reset_control_assert(reset);
+		udelay(2);
+		reset_control_deassert(reset);
+
+		reset_control_release(reset);
+	}
+
+	return stm32_omm_toggle_child_clock(dev, false);
+}
+
+static int stm32_omm_configure(struct device *dev)
+{
+	static const char * const clocks_name[] = {"omm", "ospi1", "ospi2"};
+	struct stm32_omm *omm = dev_get_drvdata(dev);
+	unsigned long clk_rate_max = 0;
+	u32 mux = 0;
+	u32 cssel_ovr = 0;
+	u32 req2ack = 0;
+	struct reset_control *rstc;
+	unsigned long clk_rate;
+	int ret;
+	u8 i;
+
+	for (i = 0; i < OMM_CLK_NB; i++)
+		omm->clk_bulk[i].id = clocks_name[i];
+
+	/* retrieve OMM, OSPI1 and OSPI2 clocks */
+	ret = devm_clk_bulk_get(dev, OMM_CLK_NB, omm->clk_bulk);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to get OMM/OSPI's clocks\n");
+
+	/* 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;
+
+	/* parse children's clock */
+	for (i = 1; i <= omm->nb_child; i++) {
+		clk_rate = clk_get_rate(omm->clk_bulk[i].clk);
+		if (!clk_rate) {
+			dev_err(dev, "Invalid clock rate\n");
+			goto error;
+		}
+
+		if (clk_rate > clk_rate_max)
+			clk_rate_max = clk_rate;
+	}
+
+	rstc = devm_reset_control_get_exclusive(dev, "omm");
+	if (IS_ERR(rstc))
+		return dev_err_probe(dev, PTR_ERR(rstc), "reset get failed\n");
+
+	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_toggle_child_clock(dev, true);
+			if (ret)
+				goto error;
+		}
+
+		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);
+
+error:
+	pm_runtime_put_sync_suspend(dev);
+
+	return ret;
+}
+
+static int stm32_omm_check_access(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_probe(struct platform_device *pdev)
+{
+	static const char * const resets_name[] = {"ospi1", "ospi2"};
+	struct device *dev = &pdev->dev;
+	u8 child_access_granted = 0;
+	struct stm32_omm *omm;
+	int i, ret;
+
+	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");
+			return -E2BIG;
+		}
+
+		ret = stm32_omm_check_access(child);
+		if (ret < 0 && ret != -EACCES)
+			return ret;
+
+		if (!ret)
+			child_access_granted++;
+
+		omm->nb_child++;
+	}
+
+	if (omm->nb_child != OMM_CHILD_NB)
+		return -EINVAL;
+
+	platform_set_drvdata(pdev, omm);
+
+	devm_pm_runtime_enable(dev);
+
+	/* check if OMM's resource access is granted */
+	ret = stm32_omm_check_access(dev->of_node);
+	if (ret < 0 && ret != -EACCES)
+		return ret;
+
+	for (i = 0; i < omm->nb_child; i++) {
+		omm->child_reset[i] = devm_reset_control_get_exclusive_released(dev,
+										resets_name[i]);
+
+		if (IS_ERR(omm->child_reset[i]))
+			return dev_err_probe(dev, PTR_ERR(omm->child_reset[i]),
+					     "Can't get %s reset\n", resets_name[i]);
+	}
+
+	if (!ret && child_access_granted == OMM_CHILD_NB) {
+		ret = stm32_omm_configure(dev);
+		if (ret)
+			return ret;
+	} 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)
+			return ret;
+	}
+
+	ret = devm_of_platform_populate(dev);
+	if (ret) {
+		if (omm->cr & CR_MUXEN)
+			stm32_omm_toggle_child_clock(&pdev->dev, false);
+
+		return dev_err_probe(dev, ret, "Failed to create Octo Memory Manager child\n");
+	}
+
+	return 0;
+}
+
+static void stm32_omm_remove(struct platform_device *pdev)
+{
+	struct stm32_omm *omm = platform_get_drvdata(pdev);
+
+	if (omm->cr & CR_MUXEN)
+		stm32_omm_toggle_child_clock(&pdev->dev, false);
+}
+
+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_bulk[0].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_bulk[0].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_toggle_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_toggle_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");