Memory controller drivers for v6.1 - Broadcom

Add support for the Broadcom STB memory controller (BRCMSTB_MEMC).
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Merge tag 'memory-controller-drv-brcm-6.1' of https://git.kernel.org/pub/scm/linux/kernel/git/krzk/linux-mem-ctrl into arm/drivers

Memory controller drivers for v6.1 - Broadcom

Add support for the Broadcom STB memory controller (BRCMSTB_MEMC).

* tag 'memory-controller-drv-brcm-6.1' of https://git.kernel.org/pub/scm/linux/kernel/git/krzk/linux-mem-ctrl:
  memory: brcmstb_memc: Add Broadcom STB memory controller driver
  Documentation: sysfs: Document Broadcom STB memc sysfs knobs
  dt-bindings: memory-controller: Document Broadcom STB MEMC

Link: https://lore.kernel.org/r/20220909153037.824092-3-krzysztof.kozlowski@linaro.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Documentation/ABI/testing/sysfs-platform-brcmstb-memc

@@ -0,0 +1,15 @@
+What:		/sys/bus/platform/devices/*/srpd
+Date:		July 2022
+KernelVersion:	5.21
+Contact:	Florian Fainelli <f.fainelli@gmail.com>
+Description:
+		Self Refresh Power Down (SRPD) inactivity timeout counted in
+		internal DDR controller clock cycles. Possible values range
+		from 0 (disable inactivity timeout) to 65535 (0xffff).
+
+What:		/sys/bus/platform/devices/*/frequency
+Date:		July 2022
+KernelVersion:	5.21
+Contact:	Florian Fainelli <f.fainelli@gmail.com>
+Description:
+		DDR PHY frequency in Hz.

Documentation/devicetree/bindings/arm/bcm/brcm,brcmstb.txt

@@ -187,15 +187,8 @@ Required properties:
 Sequencer DRAM parameters and control registers. Used for Self-Refresh
 Power-Down (SRPD), among other things.
 
-Required properties:
-- compatible     : should contain one of these
-	"brcm,brcmstb-memc-ddr-rev-b.2.1"
-	"brcm,brcmstb-memc-ddr-rev-b.2.2"
-	"brcm,brcmstb-memc-ddr-rev-b.2.3"
-	"brcm,brcmstb-memc-ddr-rev-b.3.0"
-	"brcm,brcmstb-memc-ddr-rev-b.3.1"
-	"brcm,brcmstb-memc-ddr"
-- reg            : the MEMC DDR register range
+See Documentation/devicetree/bindings/memory-controllers/brcm,brcmstb-memc-ddr.yaml for a
+full list of supported compatible strings and properties.
 
 Example:
 

Documentation/devicetree/bindings/memory-controllers/brcm,brcmstb-memc-ddr.yaml

@@ -0,0 +1,52 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/memory-controllers/brcm,brcmstb-memc-ddr.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Memory controller (MEMC) for Broadcom STB
+
+maintainers:
+  - Florian Fainelli <f.fainelli@gmail.com>
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - brcm,brcmstb-memc-ddr-rev-b.1.x
+          - brcm,brcmstb-memc-ddr-rev-b.2.0
+          - brcm,brcmstb-memc-ddr-rev-b.2.1
+          - brcm,brcmstb-memc-ddr-rev-b.2.2
+          - brcm,brcmstb-memc-ddr-rev-b.2.3
+          - brcm,brcmstb-memc-ddr-rev-b.2.5
+          - brcm,brcmstb-memc-ddr-rev-b.2.6
+          - brcm,brcmstb-memc-ddr-rev-b.2.7
+          - brcm,brcmstb-memc-ddr-rev-b.2.8
+          - brcm,brcmstb-memc-ddr-rev-b.3.0
+          - brcm,brcmstb-memc-ddr-rev-b.3.1
+          - brcm,brcmstb-memc-ddr-rev-c.1.0
+          - brcm,brcmstb-memc-ddr-rev-c.1.1
+          - brcm,brcmstb-memc-ddr-rev-c.1.2
+          - brcm,brcmstb-memc-ddr-rev-c.1.3
+          - brcm,brcmstb-memc-ddr-rev-c.1.4
+      - const: brcm,brcmstb-memc-ddr
+
+  reg:
+    maxItems: 1
+
+  clock-frequency:
+    description: DDR PHY frequency in Hz
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    memory-controller@9902000 {
+        compatible = "brcm,brcmstb-memc-ddr-rev-c.1.1", "brcm,brcmstb-memc-ddr";
+        reg = <0x9902000 0x600>;
+        clock-frequency = <2133000000>;
+    };

drivers/memory/Kconfig

@@ -66,6 +66,15 @@ config BRCMSTB_DPFE
 	  for the DRAM's temperature. Slower refresh rate means cooler RAM,
 	  higher refresh rate means hotter RAM.
 
+config BRCMSTB_MEMC
+	tristate "Broadcom STB MEMC driver"
+	default ARCH_BRCMSTB
+	depends on ARCH_BRCMSTB || COMPILE_TEST
+	help
+	  This driver provides a way to configure the Broadcom STB memory
+	  controller and specifically control the Self Refresh Power Down
+	  (SRPD) inactivity timeout.
+
 config BT1_L2_CTL
 	bool "Baikal-T1 CM2 L2-RAM Cache Control Block"
 	depends on MIPS_BAIKAL_T1 || COMPILE_TEST

drivers/memory/Makefile

@@ -11,6 +11,7 @@ obj-$(CONFIG_ARM_PL172_MPMC)	+= pl172.o
 obj-$(CONFIG_ATMEL_SDRAMC)	+= atmel-sdramc.o
 obj-$(CONFIG_ATMEL_EBI)		+= atmel-ebi.o
 obj-$(CONFIG_BRCMSTB_DPFE)	+= brcmstb_dpfe.o
+obj-$(CONFIG_BRCMSTB_MEMC)	+= brcmstb_memc.o
 obj-$(CONFIG_BT1_L2_CTL)	+= bt1-l2-ctl.o
 obj-$(CONFIG_TI_AEMIF)		+= ti-aemif.o
 obj-$(CONFIG_TI_EMIF)		+= emif.o

drivers/memory/brcmstb_memc.c

@@ -0,0 +1,301 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * DDR Self-Refresh Power Down (SRPD) support for Broadcom STB SoCs
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+
+#define REG_MEMC_CNTRLR_CONFIG		0x00
+#define  CNTRLR_CONFIG_LPDDR4_SHIFT	5
+#define  CNTRLR_CONFIG_MASK		0xf
+#define REG_MEMC_SRPD_CFG_21		0x20
+#define REG_MEMC_SRPD_CFG_20		0x34
+#define REG_MEMC_SRPD_CFG_1x		0x3c
+#define INACT_COUNT_SHIFT		0
+#define INACT_COUNT_MASK		0xffff
+#define SRPD_EN_SHIFT			16
+
+struct brcmstb_memc_data {
+	u32 srpd_offset;
+};
+
+struct brcmstb_memc {
+	struct device *dev;
+	void __iomem *ddr_ctrl;
+	unsigned int timeout_cycles;
+	u32 frequency;
+	u32 srpd_offset;
+};
+
+static int brcmstb_memc_uses_lpddr4(struct brcmstb_memc *memc)
+{
+	void __iomem *config = memc->ddr_ctrl + REG_MEMC_CNTRLR_CONFIG;
+	u32 reg;
+
+	reg = readl_relaxed(config) & CNTRLR_CONFIG_MASK;
+
+	return reg == CNTRLR_CONFIG_LPDDR4_SHIFT;
+}
+
+static int brcmstb_memc_srpd_config(struct brcmstb_memc *memc,
+				    unsigned int cycles)
+{
+	void __iomem *cfg = memc->ddr_ctrl + memc->srpd_offset;
+	u32 val;
+
+	/* Max timeout supported in HW */
+	if (cycles > INACT_COUNT_MASK)
+		return -EINVAL;
+
+	memc->timeout_cycles = cycles;
+
+	val = (cycles << INACT_COUNT_SHIFT) & INACT_COUNT_MASK;
+	if (cycles)
+		val |= BIT(SRPD_EN_SHIFT);
+
+	writel_relaxed(val, cfg);
+	/* Ensure the write is committed to the controller */
+	(void)readl_relaxed(cfg);
+
+	return 0;
+}
+
+static ssize_t frequency_show(struct device *dev,
+			      struct device_attribute *attr, char *buf)
+{
+	struct brcmstb_memc *memc = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%d\n", memc->frequency);
+}
+
+static ssize_t srpd_show(struct device *dev,
+			 struct device_attribute *attr, char *buf)
+{
+	struct brcmstb_memc *memc = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%d\n", memc->timeout_cycles);
+}
+
+static ssize_t srpd_store(struct device *dev, struct device_attribute *attr,
+			  const char *buf, size_t count)
+{
+	struct brcmstb_memc *memc = dev_get_drvdata(dev);
+	unsigned int val;
+	int ret;
+
+	/*
+	 * Cannot change the inactivity timeout on LPDDR4 chips because the
+	 * dynamic tuning process will also get affected by the inactivity
+	 * timeout, thus making it non functional.
+	 */
+	if (brcmstb_memc_uses_lpddr4(memc))
+		return -EOPNOTSUPP;
+
+	ret = kstrtouint(buf, 10, &val);
+	if (ret < 0)
+		return ret;
+
+	ret = brcmstb_memc_srpd_config(memc, val);
+	if (ret)
+		return ret;
+
+	return count;
+}
+
+static DEVICE_ATTR_RO(frequency);
+static DEVICE_ATTR_RW(srpd);
+
+static struct attribute *dev_attrs[] = {
+	&dev_attr_frequency.attr,
+	&dev_attr_srpd.attr,
+	NULL,
+};
+
+static struct attribute_group dev_attr_group = {
+	.attrs = dev_attrs,
+};
+
+static const struct of_device_id brcmstb_memc_of_match[];
+
+static int brcmstb_memc_probe(struct platform_device *pdev)
+{
+	const struct brcmstb_memc_data *memc_data;
+	const struct of_device_id *of_id;
+	struct device *dev = &pdev->dev;
+	struct brcmstb_memc *memc;
+	int ret;
+
+	memc = devm_kzalloc(dev, sizeof(*memc), GFP_KERNEL);
+	if (!memc)
+		return -ENOMEM;
+
+	dev_set_drvdata(dev, memc);
+
+	of_id = of_match_device(brcmstb_memc_of_match, dev);
+	memc_data = of_id->data;
+	memc->srpd_offset = memc_data->srpd_offset;
+
+	memc->ddr_ctrl = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(memc->ddr_ctrl))
+		return PTR_ERR(memc->ddr_ctrl);
+
+	of_property_read_u32(pdev->dev.of_node, "clock-frequency",
+			     &memc->frequency);
+
+	ret = sysfs_create_group(&dev->kobj, &dev_attr_group);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int brcmstb_memc_remove(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+
+	sysfs_remove_group(&dev->kobj, &dev_attr_group);
+
+	return 0;
+}
+
+enum brcmstb_memc_hwtype {
+	BRCMSTB_MEMC_V21,
+	BRCMSTB_MEMC_V20,
+	BRCMSTB_MEMC_V1X,
+};
+
+static const struct brcmstb_memc_data brcmstb_memc_versions[] = {
+	{ .srpd_offset = REG_MEMC_SRPD_CFG_21 },
+	{ .srpd_offset = REG_MEMC_SRPD_CFG_20 },
+	{ .srpd_offset = REG_MEMC_SRPD_CFG_1x },
+};
+
+static const struct of_device_id brcmstb_memc_of_match[] = {
+	{
+		.compatible = "brcm,brcmstb-memc-ddr-rev-b.1.x",
+		.data = &brcmstb_memc_versions[BRCMSTB_MEMC_V1X]
+	},
+	{
+		.compatible = "brcm,brcmstb-memc-ddr-rev-b.2.0",
+		.data = &brcmstb_memc_versions[BRCMSTB_MEMC_V20]
+	},
+	{
+		.compatible = "brcm,brcmstb-memc-ddr-rev-b.2.1",
+		.data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
+	},
+	{
+		.compatible = "brcm,brcmstb-memc-ddr-rev-b.2.2",
+		.data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
+	},
+	{
+		.compatible = "brcm,brcmstb-memc-ddr-rev-b.2.3",
+		.data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
+	},
+	{
+		.compatible = "brcm,brcmstb-memc-ddr-rev-b.2.5",
+		.data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
+	},
+	{
+		.compatible = "brcm,brcmstb-memc-ddr-rev-b.2.6",
+		.data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
+	},
+	{
+		.compatible = "brcm,brcmstb-memc-ddr-rev-b.2.7",
+		.data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
+	},
+	{
+		.compatible = "brcm,brcmstb-memc-ddr-rev-b.2.8",
+		.data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
+	},
+	{
+		.compatible = "brcm,brcmstb-memc-ddr-rev-b.3.0",
+		.data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
+	},
+	{
+		.compatible = "brcm,brcmstb-memc-ddr-rev-b.3.1",
+		.data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
+	},
+	{
+		.compatible = "brcm,brcmstb-memc-ddr-rev-c.1.0",
+		.data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
+	},
+	{
+		.compatible = "brcm,brcmstb-memc-ddr-rev-c.1.1",
+		.data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
+	},
+	{
+		.compatible = "brcm,brcmstb-memc-ddr-rev-c.1.2",
+		.data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
+	},
+	{
+		.compatible = "brcm,brcmstb-memc-ddr-rev-c.1.3",
+		.data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
+	},
+	{
+		.compatible = "brcm,brcmstb-memc-ddr-rev-c.1.4",
+		.data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
+	},
+	/* default to the original offset */
+	{
+		.compatible = "brcm,brcmstb-memc-ddr",
+		.data = &brcmstb_memc_versions[BRCMSTB_MEMC_V1X]
+	},
+	{}
+};
+
+static int brcmstb_memc_suspend(struct device *dev)
+{
+	struct brcmstb_memc *memc = dev_get_drvdata(dev);
+	void __iomem *cfg = memc->ddr_ctrl + memc->srpd_offset;
+	u32 val;
+
+	if (memc->timeout_cycles == 0)
+		return 0;
+
+	/*
+	 * Disable SRPD prior to suspending the system since that can
+	 * cause issues with other memory clients managed by the ARM
+	 * trusted firmware to access memory.
+	 */
+	val = readl_relaxed(cfg);
+	val &= ~BIT(SRPD_EN_SHIFT);
+	writel_relaxed(val, cfg);
+	/* Ensure the write is committed to the controller */
+	(void)readl_relaxed(cfg);
+
+	return 0;
+}
+
+static int brcmstb_memc_resume(struct device *dev)
+{
+	struct brcmstb_memc *memc = dev_get_drvdata(dev);
+
+	if (memc->timeout_cycles == 0)
+		return 0;
+
+	return brcmstb_memc_srpd_config(memc, memc->timeout_cycles);
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(brcmstb_memc_pm_ops, brcmstb_memc_suspend,
+				brcmstb_memc_resume);
+
+static struct platform_driver brcmstb_memc_driver = {
+	.probe = brcmstb_memc_probe,
+	.remove = brcmstb_memc_remove,
+	.driver = {
+		.name		= "brcmstb_memc",
+		.of_match_table	= brcmstb_memc_of_match,
+		.pm		= pm_ptr(&brcmstb_memc_pm_ops),
+	},
+};
+module_platform_driver(brcmstb_memc_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Broadcom");
+MODULE_DESCRIPTION("DDR SRPD driver for Broadcom STB chips");