[PATCH v11 2/3] memory: Add STM32 Octo Memory Manager driver

Patrice Chotard
2025-04-28T09:00:44Z

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 <christophe.kerello@foss.st.com>
Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
---
drivers/memory/Kconfig | 17 ++
drivers/memory/Makefile | 1 +
drivers/memory/stm32_omm.c | 476 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 494 insertions(+)

diff --git a/drivers/memory/Kconfig b/drivers/memory/Kconfig
index c82d8d8a16eaf154c247c0dbb9aff428b7c81402..3a0703fbfee7d1a9467cc74821604d3861fb1de0 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 d2e6ca9abbe0231c14284e3818ce734c618f83d0..c1959661bf63775bdded6dcbe87b732883c26135 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 0000000000000000000000000000000000000000..166baed0738ade5a51a793f420829668494f75ac
--- /dev/null
+++ b/drivers/memory/stm32_omm.c
@@ -0,0 +1,476 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) STMicroelectronics 2025 - All Rights Reserved
+ * Author(s): Patrice Chotard <patrice.chotard@foss.st.com> 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");

--
2.25.1