[PATCH v4 0/2] Add StarFive's StarLink Cache Controller

[PATCH v4 0/2] Add StarFive's StarLink Cache Controller

[Joshua Yeong]

StarFive's StarLink Cache Controller flush/invalidates cache using non-
conventional RISC-V Zicbom extension instructions. This driver provides the
cache handling on StarFive RISC-V SoC.

Changes in v4:
- Move cache controller initialization to arch_initcall()
- Link to v3: https://lore.kernel.org/all/20240424075856.145850-1-joshua.yeong@starfivetech.com/

Changes in v3:
- Fix code syntax
- Link to v2: https://lore.kernel.org/all/20240423072639.143450-1-joshua.yeong@starfivetech.com/

Changes in v2:
- Change patch title from 'Add StarFive's StarLink-500 Cache Controller'
- Remove StarFive alternative from errata framework
- Fixes warning from https://lore.kernel.org/oe-kbuild-all/202403151625.boKDjHGr-lkp@intel.com/
- Flush completion through atomic timeout function
- Link to v1: https://lore.kernel.org/lkml/20240314061205.26143-1-joshua.yeong@starfivetech.com/

Joshua Yeong (2):
  cache: Add StarFive StarLink cache management for StarFive JH8100
  dt-bindings: cache: Add docs for StarFive Starlink cache controller

Joshua Yeong (2):
  cache: Add StarFive StarLink cache management
  dt-bindings: cache: Add docs for StarFive Starlink cache controller

 .../cache/starfive,jh8100-starlink-cache.yaml |  66 +++++++++
 drivers/cache/Kconfig                         |   9 ++
 drivers/cache/Makefile                        |   5 +-
 drivers/cache/starfive_starlink_cache.c       | 130 ++++++++++++++++++
 4 files changed, 208 insertions(+), 2 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/cache/starfive,jh8100-starlink-cache.yaml
 create mode 100644 drivers/cache/starfive_starlink_cache.c

--
2.25.1

[PATCH v4 1/2] cache: Add StarFive StarLink cache management

[Joshua Yeong]

Add StarFive Starlink cache management driver.
The driver enables RISC-V non-standard cache
operation on SoC that does not support Zicbom
extension instructions.

Signed-off-by: Joshua Yeong <joshua.yeong@starfivetech.com>
---
 drivers/cache/Kconfig                   |   9 ++
 drivers/cache/Makefile                  |   5 +-
 drivers/cache/starfive_starlink_cache.c | 130 ++++++++++++++++++++++++
 3 files changed, 142 insertions(+), 2 deletions(-)
 create mode 100644 drivers/cache/starfive_starlink_cache.c

diff --git a/drivers/cache/Kconfig b/drivers/cache/Kconfig
index 9345ce4976d7..94abd8f632a7 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 STARFIVE_STARLINK_CACHE
+	bool "StarFive StarLink Cache controller"
+	depends on RISCV
+	depends on ARCH_STARFIVE
+	select RISCV_DMA_NONCOHERENT
+	select RISCV_NONSTANDARD_CACHE_OPS
+	help
+	  Support for the StarLink cache controller IP from StarFive.
+
 endmenu
diff --git a/drivers/cache/Makefile b/drivers/cache/Makefile
index 7657cff3bd6c..55c5e851034d 100644
--- a/drivers/cache/Makefile
+++ b/drivers/cache/Makefile
@@ -1,4 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
 
-obj-$(CONFIG_AX45MP_L2_CACHE)	+= ax45mp_cache.o
-obj-$(CONFIG_SIFIVE_CCACHE)	+= sifive_ccache.o
+obj-$(CONFIG_AX45MP_L2_CACHE)		+= ax45mp_cache.o
+obj-$(CONFIG_SIFIVE_CCACHE)		+= sifive_ccache.o
+obj-$(CONFIG_STARFIVE_STARLINK_CACHE)	+= starfive_starlink_cache.o
diff --git a/drivers/cache/starfive_starlink_cache.c b/drivers/cache/starfive_starlink_cache.c
new file mode 100644
index 000000000000..24c7d078ca22
--- /dev/null
+++ b/drivers/cache/starfive_starlink_cache.c
@@ -0,0 +1,130 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Cache Management Operations for StarFive's Starlink cache controller
+ *
+ * Copyright (C) 2024 Shanghai StarFive Technology Co., Ltd.
+ *
+ * Author: Joshua Yeong <joshua.yeong@starfivetech.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/cacheflush.h>
+#include <linux/iopoll.h>
+#include <linux/of_address.h>
+
+#include <asm/dma-noncoherent.h>
+
+#define STARLINK_CACHE_FLUSH_START_ADDR			0x0
+#define STARLINK_CACHE_FLUSH_END_ADDR			0x8
+#define STARLINK_CACHE_FLUSH_CTL			0x10
+#define STARLINK_CACHE_ALIGN				0x40
+
+#define STARLINK_CACHE_ADDRESS_RANGE_MASK		GENMASK(39, 0)
+#define STARLINK_CACHE_FLUSH_CTL_MODE_MASK		GENMASK(2, 1)
+#define STARLINK_CACHE_FLUSH_CTL_ENABLE_MASK		BIT(0)
+
+#define STARLINK_CACHE_FLUSH_CTL_CLEAN_INVALIDATE	0
+#define STARLINK_CACHE_FLUSH_CTL_MAKE_INVALIDATE	1
+#define STARLINK_CACHE_FLUSH_CTL_CLEAN_SHARED		2
+#define STARLINK_CACHE_FLUSH_POLL_DELAY_US		1
+#define STARLINK_CACHE_FLUSH_TIMEOUT_US			5000000
+
+static void __iomem *starlink_cache_base;
+
+static void starlink_cache_flush_complete(void)
+{
+	volatile void __iomem *ctl = starlink_cache_base + STARLINK_CACHE_FLUSH_CTL;
+	u64 v;
+	int ret;
+
+	ret = readq_poll_timeout_atomic(ctl, v, !(v & STARLINK_CACHE_FLUSH_CTL_ENABLE_MASK),
+					STARLINK_CACHE_FLUSH_POLL_DELAY_US,
+					STARLINK_CACHE_FLUSH_TIMEOUT_US);
+	if (ret)
+		WARN(1, "StarFive Starlink cache flush operation timeout\n");
+}
+
+static void starlink_cache_dma_cache_wback(phys_addr_t paddr, unsigned long size)
+{
+	writeq(FIELD_PREP(STARLINK_CACHE_ADDRESS_RANGE_MASK, paddr),
+	       starlink_cache_base + STARLINK_CACHE_FLUSH_START_ADDR);
+	writeq(FIELD_PREP(STARLINK_CACHE_ADDRESS_RANGE_MASK, paddr + size),
+	       starlink_cache_base + STARLINK_CACHE_FLUSH_END_ADDR);
+
+	mb();
+	writeq(FIELD_PREP(STARLINK_CACHE_FLUSH_CTL_MODE_MASK,
+			  STARLINK_CACHE_FLUSH_CTL_CLEAN_SHARED),
+	       starlink_cache_base + STARLINK_CACHE_FLUSH_CTL);
+
+	starlink_cache_flush_complete();
+}
+
+static void starlink_cache_dma_cache_invalidate(phys_addr_t paddr, unsigned long size)
+{
+	writeq(FIELD_PREP(STARLINK_CACHE_ADDRESS_RANGE_MASK, paddr),
+	       starlink_cache_base + STARLINK_CACHE_FLUSH_START_ADDR);
+	writeq(FIELD_PREP(STARLINK_CACHE_ADDRESS_RANGE_MASK, paddr + size),
+	       starlink_cache_base + STARLINK_CACHE_FLUSH_END_ADDR);
+
+	mb();
+	writeq(FIELD_PREP(STARLINK_CACHE_FLUSH_CTL_MODE_MASK,
+			  STARLINK_CACHE_FLUSH_CTL_MAKE_INVALIDATE),
+	       starlink_cache_base + STARLINK_CACHE_FLUSH_CTL);
+
+	starlink_cache_flush_complete();
+}
+
+static void starlink_cache_dma_cache_wback_inv(phys_addr_t paddr, unsigned long size)
+{
+	writeq(FIELD_PREP(STARLINK_CACHE_ADDRESS_RANGE_MASK, paddr),
+	       starlink_cache_base + STARLINK_CACHE_FLUSH_START_ADDR);
+	writeq(FIELD_PREP(STARLINK_CACHE_ADDRESS_RANGE_MASK, paddr + size),
+	       starlink_cache_base + STARLINK_CACHE_FLUSH_END_ADDR);
+
+	mb();
+	writeq(FIELD_PREP(STARLINK_CACHE_FLUSH_CTL_MODE_MASK,
+			  STARLINK_CACHE_FLUSH_CTL_CLEAN_INVALIDATE),
+	       starlink_cache_base + STARLINK_CACHE_FLUSH_CTL);
+
+	starlink_cache_flush_complete();
+}
+
+static const struct riscv_nonstd_cache_ops starlink_cache_ops = {
+	.wback = &starlink_cache_dma_cache_wback,
+	.inv = &starlink_cache_dma_cache_invalidate,
+	.wback_inv = &starlink_cache_dma_cache_wback_inv,
+};
+
+static const struct of_device_id starlink_cache_ids[] = {
+	{ .compatible = "starfive,jh8100-starlink-cache" },
+	{ /* sentinel */ }
+};
+
+static int __init starlink_cache_init(void)
+{
+	struct device_node *np;
+	u32 block_size;
+	int ret;
+
+	np = of_find_matching_node(NULL, starlink_cache_ids);
+	if (!of_device_is_available(np))
+		return -ENODEV;
+
+	ret = of_property_read_u32(np, "cache-block-size", &block_size);
+	if (ret)
+		return ret;
+
+	if (block_size % STARLINK_CACHE_ALIGN)
+		return -EINVAL;
+
+	starlink_cache_base = of_iomap(np, 0);
+	if (!starlink_cache_base)
+		return -ENOMEM;
+
+	riscv_cbom_block_size = block_size;
+	riscv_noncoherent_supported();
+	riscv_noncoherent_register_cache_ops(&starlink_cache_ops);
+
+	return 0;
+}
+arch_initcall(starlink_cache_init);
-- 
2.25.1

[PATCH v4 2/2] dt-bindings: cache: Add docs for StarFive Starlink cache controller

[Joshua Yeong]

Add DT binding documentation used by StarFive's
Starlink cache controller.

Signed-off-by: Joshua Yeong <joshua.yeong@starfivetech.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
---
 .../cache/starfive,jh8100-starlink-cache.yaml | 66 +++++++++++++++++++
 1 file changed, 66 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/cache/starfive,jh8100-starlink-cache.yaml

diff --git a/Documentation/devicetree/bindings/cache/starfive,jh8100-starlink-cache.yaml b/Documentation/devicetree/bindings/cache/starfive,jh8100-starlink-cache.yaml
new file mode 100644
index 000000000000..6d61098e388b
--- /dev/null
+++ b/Documentation/devicetree/bindings/cache/starfive,jh8100-starlink-cache.yaml
@@ -0,0 +1,66 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/cache/starfive,jh8100-starlink-cache.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: StarFive StarLink Cache Controller
+
+maintainers:
+  - Joshua Yeong <joshua.yeong@starfivetech.com>
+
+description:
+  StarFive's StarLink Cache Controller manages the L3 cache shared between
+  clusters of CPU cores. The cache driver enables RISC-V non-standard cache
+  management as an alternative to instructions in the RISC-V Zicbom extension.
+
+allOf:
+  - $ref: /schemas/cache-controller.yaml#
+
+# We need a select here so we don't match all nodes with 'cache'
+select:
+  properties:
+    compatible:
+      contains:
+        enum:
+          - starfive,jh8100-starlink-cache
+
+  required:
+    - compatible
+
+properties:
+  compatible:
+    items:
+      - const: starfive,jh8100-starlink-cache
+      - const: cache
+
+  reg:
+    maxItems: 1
+
+unevaluatedProperties: false
+
+required:
+  - compatible
+  - reg
+  - cache-block-size
+  - cache-level
+  - cache-sets
+  - cache-size
+  - cache-unified
+
+examples:
+  - |
+      soc {
+        #address-cells = <2>;
+        #size-cells = <2>;
+
+        cache-controller@15000000 {
+          compatible = "starfive,jh8100-starlink-cache", "cache";
+          reg = <0x0 0x15000000 0x0 0x278>;
+          cache-block-size = <64>;
+          cache-level = <3>;
+          cache-sets = <8192>;
+          cache-size = <0x400000>;
+          cache-unified;
+        };
+      };
-- 
2.25.1