[PATCH v3 6/8] cache: Support cache maintenance for HiSilicon SoC Hydra Home Agent

[Jonathan Cameron <Jonathan.Cameron@huawei.com>]

From: Yushan Wang <wangyushan12@huawei.com>

Hydra Home Agent is a device used to maintain cache coherency. Add support
of explicit cache maintenance operations for it.

Memory resource of HHA conflicts with that of HHA PMU. A workaround is
implemented here by replacing devm_ioremap_resource() to devm_ioremap() to
workaround the resource conflict check.

Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Co-developed-by: Yicong Yang <yangyicong@hisilicon.com>
Signed-off-by: Yushan Wang <wangyushan12@huawei.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 drivers/cache/Kconfig        |  15 +++
 drivers/cache/Makefile       |   2 +
 drivers/cache/hisi_soc_hha.c | 187 +++++++++++++++++++++++++++++++++++
 3 files changed, 204 insertions(+)

diff --git a/drivers/cache/Kconfig b/drivers/cache/Kconfig
index db51386c663a..4551b28e14dd 100644
--- a/drivers/cache/Kconfig
+++ b/drivers/cache/Kconfig
@@ -1,6 +1,21 @@
 # SPDX-License-Identifier: GPL-2.0
 menu "Cache Drivers"
 
+if GENERIC_CPU_CACHE_MAINTENANCE
+
+config HISI_SOC_HHA
+	tristate "HiSilicon Hydra Home Agent (HHA) device driver"
+	depends on (ARM64 && ACPI) || COMPILE_TEST
+	help
+	  The Hydra Home Agent (HHA) is responsible for cache coherency
+	  on the SoC. This drivers enables the cache maintenance functions of
+	  the HHA.
+
+	  This driver can be built as a module. If so, the module will be
+	  called hisi_soc_hha.
+
+endif
+
 config AX45MP_L2_CACHE
 	bool "Andes Technology AX45MP L2 Cache controller"
 	depends on RISCV
diff --git a/drivers/cache/Makefile b/drivers/cache/Makefile
index 55c5e851034d..b3362b15d6c1 100644
--- a/drivers/cache/Makefile
+++ b/drivers/cache/Makefile
@@ -3,3 +3,5 @@
 obj-$(CONFIG_AX45MP_L2_CACHE)		+= ax45mp_cache.o
 obj-$(CONFIG_SIFIVE_CCACHE)		+= sifive_ccache.o
 obj-$(CONFIG_STARFIVE_STARLINK_CACHE)	+= starfive_starlink_cache.o
+
+obj-$(CONFIG_HISI_SOC_HHA)		+= hisi_soc_hha.o
diff --git a/drivers/cache/hisi_soc_hha.c b/drivers/cache/hisi_soc_hha.c
new file mode 100644
index 000000000000..9a26a562804e
--- /dev/null
+++ b/drivers/cache/hisi_soc_hha.c
@@ -0,0 +1,187 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for HiSilicon Hydra Home Agent (HHA).
+ *
+ * Copyright (c) 2025 HiSilicon Technologies Co., Ltd.
+ * Author: Yicong Yang <yangyicong@hisilicon.com>
+ *         Yushan Wang <wangyushan12@huawei.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/cacheflush.h>
+#include <linux/cache_coherency.h>
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/kernel.h>
+#include <linux/memregion.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+
+#define HISI_HHA_CTRL		0x5004
+#define   HISI_HHA_CTRL_EN	BIT(0)
+#define   HISI_HHA_CTRL_RANGE	BIT(1)
+#define   HISI_HHA_CTRL_TYPE	GENMASK(3, 2)
+#define HISI_HHA_START_L	0x5008
+#define HISI_HHA_START_H	0x500c
+#define HISI_HHA_LEN_L		0x5010
+#define HISI_HHA_LEN_H		0x5014
+
+/* The maintain operation performs in a 128 Byte granularity */
+#define HISI_HHA_MAINT_ALIGN	128
+
+#define HISI_HHA_POLL_GAP_US		10
+#define HISI_HHA_POLL_TIMEOUT_US	50000
+
+struct hisi_soc_hha {
+	/* Must be first element */
+	struct cache_coherency_device ccd;
+	/* Locks HHA instance to forbid overlapping access. */
+	struct mutex lock;
+	void __iomem *base;
+};
+
+static bool hisi_hha_cache_maintain_wait_finished(struct hisi_soc_hha *soc_hha)
+{
+	u32 val;
+
+	return !readl_poll_timeout_atomic(soc_hha->base + HISI_HHA_CTRL, val,
+					  !(val & HISI_HHA_CTRL_EN),
+					  HISI_HHA_POLL_GAP_US,
+					  HISI_HHA_POLL_TIMEOUT_US);
+}
+
+static int hisi_soc_hha_wbinv(struct cache_coherency_device *ccd, struct cc_inval_params *invp)
+{
+	struct hisi_soc_hha *soc_hha = container_of(ccd, struct hisi_soc_hha, ccd);
+	phys_addr_t top, addr = invp->addr;
+	size_t size = invp->size;
+	u32 reg;
+
+	if (!size)
+		return -EINVAL;
+
+	addr = ALIGN_DOWN(addr, HISI_HHA_MAINT_ALIGN);
+	top = ALIGN(addr + size, HISI_HHA_MAINT_ALIGN);
+	size = top - addr;
+
+	guard(mutex)(&soc_hha->lock);
+
+	if (!hisi_hha_cache_maintain_wait_finished(soc_hha))
+		return -EBUSY;
+
+	/*
+	 * Hardware will search for addresses ranging [addr, addr + size - 1],
+	 * last byte included, and perform maintain in 128 byte granule
+	 * on those cachelines which contain the addresses.
+	 */
+	size -= 1;
+
+	writel(lower_32_bits(addr), soc_hha->base + HISI_HHA_START_L);
+	writel(upper_32_bits(addr), soc_hha->base + HISI_HHA_START_H);
+	writel(lower_32_bits(size), soc_hha->base + HISI_HHA_LEN_L);
+	writel(upper_32_bits(size), soc_hha->base + HISI_HHA_LEN_H);
+
+	reg = FIELD_PREP(HISI_HHA_CTRL_TYPE, 1); /* Clean Invalid */
+	reg |= HISI_HHA_CTRL_RANGE | HISI_HHA_CTRL_EN;
+	writel(reg, soc_hha->base + HISI_HHA_CTRL);
+
+	return 0;
+}
+
+static int hisi_soc_hha_done(struct cache_coherency_device *ccd)
+{
+	struct hisi_soc_hha *soc_hha = container_of(ccd, struct hisi_soc_hha, ccd);
+
+	guard(mutex)(&soc_hha->lock);
+	if (!hisi_hha_cache_maintain_wait_finished(soc_hha))
+		return -ETIMEDOUT;
+
+	return 0;
+}
+
+static const struct coherency_ops hha_ops = {
+	.wbinv = hisi_soc_hha_wbinv,
+	.done = hisi_soc_hha_done,
+};
+
+static int hisi_soc_hha_probe(struct platform_device *pdev)
+{
+	struct hisi_soc_hha *soc_hha;
+	struct resource *mem;
+	int ret;
+
+	soc_hha = cache_coherency_device_alloc(&hha_ops, struct hisi_soc_hha,
+					       ccd);
+	if (!soc_hha)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, soc_hha);
+
+	mutex_init(&soc_hha->lock);
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!mem)
+		return -ENODEV;
+
+	/*
+	 * HHA cache driver share the same register region with HHA uncore PMU
+	 * driver in hardware's perspective, none of them should reserve the
+	 * resource to itself only.  Here exclusive access verification is
+	 * avoided by calling devm_ioremap instead of devm_ioremap_resource to
+	 * allow both drivers to exist at the same time.
+	 */
+	soc_hha->base = ioremap(mem->start, resource_size(mem));
+	if (IS_ERR_OR_NULL(soc_hha->base)) {
+		ret = dev_err_probe(&pdev->dev, PTR_ERR(soc_hha->base),
+				"failed to remap io memory");
+		goto err_free_ccd;
+	}
+
+	ret = cache_coherency_device_register(&soc_hha->ccd);
+	if (ret)
+		goto err_iounmap;
+
+	return 0;
+
+err_iounmap:
+	iounmap(soc_hha->base);
+err_free_ccd:
+	cache_coherency_device_free(&soc_hha->ccd);
+	return ret;
+}
+
+static void hisi_soc_hha_remove(struct platform_device *pdev)
+{
+	struct hisi_soc_hha *soc_hha = platform_get_drvdata(pdev);
+
+	cache_coherency_device_unregister(&soc_hha->ccd);
+	iounmap(soc_hha->base);
+	cache_coherency_device_free(&soc_hha->ccd);
+}
+
+static const struct acpi_device_id hisi_soc_hha_ids[] = {
+	{ "HISI0511", },
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, hisi_soc_hha_ids);
+
+static struct platform_driver hisi_soc_hha_driver = {
+	.driver = {
+		.name = "hisi_soc_hha",
+		.acpi_match_table = hisi_soc_hha_ids,
+	},
+	.probe = hisi_soc_hha_probe,
+	.remove = hisi_soc_hha_remove,
+};
+
+module_platform_driver(hisi_soc_hha_driver);
+
+MODULE_IMPORT_NS("CACHE_COHERENCY");
+MODULE_DESCRIPTION("HiSilicon Hydra Home Agent driver supporting cache maintenance");
+MODULE_AUTHOR("Yicong Yang <yangyicong@hisilicon.com>");
+MODULE_AUTHOR("Yushan Wang <wangyushan12@huawei.com>");
+MODULE_LICENSE("GPL");
-- 
2.48.1