[PATCH 3/4] cache: Add StarLink-500 cache management for StarFive JH8100 RISC-V core

[Joshua Yeong]

Add software workaround for StarFive StarLink-500
on JH8100 SoC for CMO extension instructions.

Signed-off-by: Joshua Yeong <joshua.yeong@xxxxxxxxxxxxxxxx>
---
 drivers/cache/Kconfig             |   9 ++
 drivers/cache/Makefile            |   1 +
 drivers/cache/starlink500_cache.c | 137 ++++++++++++++++++++++++++++++
 3 files changed, 147 insertions(+)
 create mode 100644 drivers/cache/starlink500_cache.c

diff --git a/drivers/cache/Kconfig b/drivers/cache/Kconfig
index 9345ce4976d7..e215379f6a73 100644
--- a/drivers/cache/Kconfig
+++ b/drivers/cache/Kconfig
@@ -14,4 +14,13 @@ config SIFIVE_CCACHE
 	help
 	  Support for the composable cache controller on SiFive platforms.
 
+config STARLINK_500_CACHE
+	bool "StarLink-500 Cache controller"
+	depends on RISCV_DMA_NONCOHERENT
+	depends on ERRATA_STARFIVE
+	select RISCV_NONSTANDARD_CACHE_OPS
+	default y
+	help
+	  Support for the StarLink-500 cache controller on StarFive platforms.
+
 endmenu
diff --git a/drivers/cache/Makefile b/drivers/cache/Makefile
index 7657cff3bd6c..c515eb5714ea 100644
--- a/drivers/cache/Makefile
+++ b/drivers/cache/Makefile
@@ -2,3 +2,4 @@
 
 obj-$(CONFIG_AX45MP_L2_CACHE)	+= ax45mp_cache.o
 obj-$(CONFIG_SIFIVE_CCACHE)	+= sifive_ccache.o
+obj-$(CONFIG_STARLINK_500_CACHE) += starlink500_cache.o
diff --git a/drivers/cache/starlink500_cache.c b/drivers/cache/starlink500_cache.c
new file mode 100644
index 000000000000..eaf8303cb086
--- /dev/null
+++ b/drivers/cache/starlink500_cache.c
@@ -0,0 +1,137 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Non-coherent cache functions for StarFive's StarLink-500 cache controller
+ *
+ * Copyright (C) 2024 Shanghai StarFive Technology Co., Ltd.
+ *
+ * Author: Joshua Yeong <joshua.yeong@xxxxxxxxxxxxxxxx>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/cacheflush.h>
+#include <linux/cacheinfo.h>
+#include <linux/delay.h>
+#include <linux/dma-direction.h>
+#include <linux/io.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/processor.h>
+
+#include <asm/dma-noncoherent.h>
+
+#define STARFIVE_SL500_CMO_FLUSH_START_ADDR		0x0
+#define STARFIVE_SL500_CMO_FLUSH_END_ADDR		0x8
+#define STARFIVE_SL500_CMO_FLUSH_CTL			0x10
+#define STARFIVE_SL500_CMO_CACHE_ALIGN			0x40
+
+#define STARFIVE_SL500_ADDRESS_RANGE_MASK		GENMASK(39, 0)
+#define STARFIVE_SL500_FLUSH_CTL_MODE_MASK		GENMASK(2, 1)
+#define STARFIVE_SL500_FLUSH_CTL_ENABLE_MASK		BIT(0)
+
+#define STARFIVE_SL500_FLUSH_CTL_CLEAN_INVALIDATE	0
+#define STARFIVE_SL500_FLUSH_CTL_MAKE_INVALIDATE	1
+#define STARFIVE_SL500_FLUSH_CTL_CLEAN_SHARED		2
+
+struct starfive_sl500_cache_priv {
+	void __iomem *base_addr;
+};
+
+static struct starfive_sl500_cache_priv starfive_sl500_cache_priv;
+
+static void starfive_sl500_cmo_flush_complete(void)
+{
+	ktime_t timeout;
+
+	volatile void __iomem *_ctl = starfive_sl500_cache_priv.base_addr +
+                                      STARFIVE_SL500_CMO_FLUSH_CTL;
+	timeout = ktime_add_ms(ktime_get(), 5000);
+
+	do {
+		if(!(ioread64(_ctl) & STARFIVE_SL500_FLUSH_CTL_ENABLE_MASK))
+			return;
+		msleep(50);
+	} while (ktime_before(ktime_get(), timeout));
+
+	pr_err("StarFive CMO operation timeout\n");
+	dump_stack();
+}
+
+void starfive_sl500_dma_cache_wback(phys_addr_t paddr, unsigned long size)
+{
+	writeq(FIELD_PREP(STARFIVE_SL500_ADDRESS_RANGE_MASK, paddr),
+	       starfive_sl500_cache_priv.base_addr + STARFIVE_SL500_CMO_FLUSH_START_ADDR);
+	writeq(FIELD_PREP(STARFIVE_SL500_ADDRESS_RANGE_MASK, paddr + size),
+	       starfive_sl500_cache_priv.base_addr + STARFIVE_SL500_CMO_FLUSH_END_ADDR);
+
+	mb();
+	writeq(FIELD_PREP(STARFIVE_SL500_FLUSH_CTL_MODE_MASK,
+	       STARFIVE_SL500_FLUSH_CTL_CLEAN_SHARED),
+	       starfive_sl500_cache_priv.base_addr + STARFIVE_SL500_CMO_FLUSH_CTL);
+
+	starfive_sl500_cmo_flush_complete();
+}
+
+void starfive_sl500_dma_cache_invalidate(phys_addr_t paddr, unsigned long size)
+{
+	writeq(FIELD_PREP(STARFIVE_SL500_ADDRESS_RANGE_MASK, paddr),
+	       starfive_sl500_cache_priv.base_addr + STARFIVE_SL500_CMO_FLUSH_START_ADDR);
+	writeq(FIELD_PREP(STARFIVE_SL500_ADDRESS_RANGE_MASK, paddr + size),
+	       starfive_sl500_cache_priv.base_addr + STARFIVE_SL500_CMO_FLUSH_END_ADDR);
+
+	mb();
+	writeq(FIELD_PREP(STARFIVE_SL500_FLUSH_CTL_MODE_MASK,
+	       STARFIVE_SL500_FLUSH_CTL_MAKE_INVALIDATE),
+	       starfive_sl500_cache_priv.base_addr + STARFIVE_SL500_CMO_FLUSH_CTL);
+
+	starfive_sl500_cmo_flush_complete();
+}
+
+void starfive_sl500_dma_cache_wback_inv(phys_addr_t paddr, unsigned long size)
+{
+	writeq(FIELD_PREP(STARFIVE_SL500_ADDRESS_RANGE_MASK, paddr),
+	       starfive_sl500_cache_priv.base_addr + STARFIVE_SL500_CMO_FLUSH_START_ADDR);
+	writeq(FIELD_PREP(STARFIVE_SL500_ADDRESS_RANGE_MASK, paddr + size),
+	       starfive_sl500_cache_priv.base_addr + STARFIVE_SL500_CMO_FLUSH_END_ADDR);
+
+	mb();
+	writeq(FIELD_PREP(STARFIVE_SL500_FLUSH_CTL_MODE_MASK,
+	       STARFIVE_SL500_FLUSH_CTL_CLEAN_INVALIDATE),
+	       starfive_sl500_cache_priv.base_addr + STARFIVE_SL500_CMO_FLUSH_CTL);
+
+	starfive_sl500_cmo_flush_complete();
+}
+
+static const struct riscv_nonstd_cache_ops starfive_sl500_cmo_ops = {
+	.wback = &starfive_sl500_dma_cache_wback,
+	.inv = &starfive_sl500_dma_cache_invalidate,
+	.wback_inv = &starfive_sl500_dma_cache_wback_inv,
+};
+
+static const struct of_device_id starfive_sl500_cache_ids[] = {
+	{ .compatible = "starfive,starlink-500-cache" },
+	{ /* sentinel */ }
+};
+
+static int __init starfive_sl500_cache_init(void)
+{
+	struct device_node *np;
+	struct resource res;
+	int ret;
+
+	np = of_find_matching_node(NULL, starfive_sl500_cache_ids);
+	if (!of_device_is_available(np))
+		return -ENODEV;
+
+	ret = of_address_to_resource(np, 0, &res);
+	if (ret)
+		return ret;
+
+	starfive_sl500_cache_priv.base_addr = ioremap(res.start, resource_size(&res));
+	if (!starfive_sl500_cache_priv.base_addr)
+		return -ENOMEM;
+
+	riscv_noncoherent_register_cache_ops(&starfive_sl500_cmo_ops);
+
+	return 0;
+}
+early_initcall(starfive_sl500_cache_init);
-- 
2.25.1