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Subject[PATCH v5 6/6] soc: renesas: Add L2 cache management for RZ/Five SoC
Date
From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

I/O Coherence Port (IOCP) provides an AXI interface for connecting
external non-caching masters, such as DMA controllers. The accesses
from IOCP are coherent with D-Caches and L2 Cache.

IOCP is a specification option and is disabled on the Renesas RZ/Five
SoC due to this reason IP blocks using DMA will fail.

The Andes AX45MP core has a Programmable Physical Memory Attributes (PMA)
block that allows dynamic adjustment of memory attributes in the runtime.
It contains a configurable amount of PMA entries implemented as CSR
registers to control the attributes of memory locations in interest.
Below are the memory attributes supported:
* Device, Non-bufferable
* Device, bufferable
* Memory, Non-cacheable, Non-bufferable
* Memory, Non-cacheable, Bufferable
* Memory, Write-back, No-allocate
* Memory, Write-back, Read-allocate
* Memory, Write-back, Write-allocate
* Memory, Write-back, Read and Write-allocate

More info about PMA (section 10.3):
Link: http://www.andestech.com/wp-content/uploads/AX45MP-1C-Rev.-5.0.0-Datasheet.pdf

As a workaround for SoCs with IOCP disabled CMO needs to be handled by
software. Firstly OpenSBI configures the memory region as
"Memory, Non-cacheable, Bufferable" and passes this region as a global
shared dma pool as a DT node. With DMA_GLOBAL_POOL enabled all DMA
allocations happen from this region and synchronization callbacks are
implemented to synchronize when doing DMA transactions.

Example PMA region passes as a DT node from OpenSBI:
reserved-memory {
#address-cells = <2>;
#size-cells = <2>;
ranges;

pma_resv0@58000000 {
compatible = "shared-dma-pool";
reg = <0x0 0x58000000 0x0 0x08000000>;
no-map;
linux,dma-default;
};
};

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
---
v4 -> v5
* Dropped code for configuring L2 cache
* Dropped code for configuring PMA
* Updated commit message
* Added comments
* Changed static branch enable/disable order

RFC v3 -> v4
* Made use of runtime patching instead of compile time
* Now just exposing single function ax45mp_no_iocp_cmo() for CMO handling
* Added a check to make sure cache line size is always 64 bytes
* Renamed folder rzf -> rzfive
* Improved Kconfig description
* Dropped L2 cache configuration
* Dropped unnecessary casts
* Fixed comments pointed by Geert.
---
arch/riscv/include/asm/cacheflush.h | 8 +
arch/riscv/include/asm/errata_list.h | 28 ++-
drivers/soc/renesas/Kconfig | 6 +
drivers/soc/renesas/Makefile | 2 +
drivers/soc/renesas/rzfive/Kconfig | 6 +
drivers/soc/renesas/rzfive/Makefile | 3 +
drivers/soc/renesas/rzfive/ax45mp_cache.c | 256 ++++++++++++++++++++++
7 files changed, 303 insertions(+), 6 deletions(-)
create mode 100644 drivers/soc/renesas/rzfive/Kconfig
create mode 100644 drivers/soc/renesas/rzfive/Makefile
create mode 100644 drivers/soc/renesas/rzfive/ax45mp_cache.c

diff --git a/arch/riscv/include/asm/cacheflush.h b/arch/riscv/include/asm/cacheflush.h
index e22019668b9e..d0e15636866c 100644
--- a/arch/riscv/include/asm/cacheflush.h
+++ b/arch/riscv/include/asm/cacheflush.h
@@ -68,6 +68,14 @@ static inline void riscv_noncoherent_supported(void) {}
#define SYS_RISCV_FLUSH_ICACHE_LOCAL 1UL
#define SYS_RISCV_FLUSH_ICACHE_ALL (SYS_RISCV_FLUSH_ICACHE_LOCAL)

+#ifdef CONFIG_AX45MP_L2_CACHE
+extern asmlinkage void ax45mp_no_iocp_cmo(unsigned int cache_size, void *vaddr,
+ size_t size, int dir, int ops);
+#else
+static inline void ax45mp_no_iocp_cmo(unsigned int cache_size, void *vaddr,
+ size_t size, int dir, int ops) {}
+#endif
+
#include <asm-generic/cacheflush.h>

#endif /* _ASM_RISCV_CACHEFLUSH_H */
diff --git a/arch/riscv/include/asm/errata_list.h b/arch/riscv/include/asm/errata_list.h
index 48e899a8e7a9..9a017142e67f 100644
--- a/arch/riscv/include/asm/errata_list.h
+++ b/arch/riscv/include/asm/errata_list.h
@@ -125,8 +125,8 @@ asm volatile(ALTERNATIVE( \
#define THEAD_SYNC_S ".long 0x0190000b"

#define ALT_CMO_OP(_op, _start, _size, _cachesize, _dir, _ops) \
-asm volatile(ALTERNATIVE_2( \
- __nops(6), \
+asm volatile(ALTERNATIVE_3( \
+ __nops(14), \
"mv a0, %1\n\t" \
"j 2f\n\t" \
"3:\n\t" \
@@ -134,7 +134,7 @@ asm volatile(ALTERNATIVE_2( \
"add a0, a0, %0\n\t" \
"2:\n\t" \
"bltu a0, %2, 3b\n\t" \
- "nop", 0, CPUFEATURE_ZICBOM, CONFIG_RISCV_ISA_ZICBOM, \
+ __nops(9), 0, CPUFEATURE_ZICBOM, CONFIG_RISCV_ISA_ZICBOM, \
"mv a0, %1\n\t" \
"j 2f\n\t" \
"3:\n\t" \
@@ -142,8 +142,24 @@ asm volatile(ALTERNATIVE_2( \
"add a0, a0, %0\n\t" \
"2:\n\t" \
"bltu a0, %2, 3b\n\t" \
- THEAD_SYNC_S, THEAD_VENDOR_ID, \
- ERRATA_THEAD_CMO, CONFIG_ERRATA_THEAD_CMO) \
+ THEAD_SYNC_S "\n\t" \
+ __nops(8), THEAD_VENDOR_ID, \
+ ERRATA_THEAD_CMO, CONFIG_ERRATA_THEAD_CMO, \
+ "addi sp,sp,-16\n\t" \
+ "sd s0,0(sp)\n\t" \
+ "sd ra,8(sp)\n\t" \
+ "addi s0,sp,16\n\t" \
+ "mv a4,%6\n\t" \
+ "mv a3,%5\n\t" \
+ "mv a2,%4\n\t" \
+ "mv a1,%3\n\t" \
+ "mv a0,%0\n\t" \
+ "call ax45mp_no_iocp_cmo\n\t" \
+ "ld ra,8(sp)\n\t" \
+ "ld s0,0(sp)\n\t" \
+ "addi sp,sp,16\n\t", \
+ ANDESTECH_VENDOR_ID, ERRATA_ANDESTECH_NO_IOCP, \
+ CONFIG_ERRATA_ANDES_CMO) \
: : "r"(_cachesize), \
"r"((unsigned long)(_start) & ~((_cachesize) - 1UL)), \
"r"((unsigned long)(_start) + (_size)), \
@@ -151,7 +167,7 @@ asm volatile(ALTERNATIVE_2( \
"r"((unsigned long)(_size)), \
"r"((unsigned long)(_dir)), \
"r"((unsigned long)(_ops)) \
- : "a0")
+ : "a0", "a1", "a2", "a3", "a4", "memory")

#define THEAD_C9XX_RV_IRQ_PMU 17
#define THEAD_C9XX_CSR_SCOUNTEROF 0x5c5
diff --git a/drivers/soc/renesas/Kconfig b/drivers/soc/renesas/Kconfig
index 660498252ec5..a6627936b79e 100644
--- a/drivers/soc/renesas/Kconfig
+++ b/drivers/soc/renesas/Kconfig
@@ -340,9 +340,15 @@ if RISCV
config ARCH_R9A07G043
bool "RISC-V Platform support for RZ/Five"
select ARCH_RZG2L
+ select AX45MP_L2_CACHE
+ select DMA_GLOBAL_POOL
+ select ERRATA_ANDES
+ select ERRATA_ANDES_CMO
help
This enables support for the Renesas RZ/Five SoC.

+source "drivers/soc/renesas/rzfive/Kconfig"
+
endif # RISCV

config RST_RCAR
diff --git a/drivers/soc/renesas/Makefile b/drivers/soc/renesas/Makefile
index 535868c9c7e4..9df9f759a039 100644
--- a/drivers/soc/renesas/Makefile
+++ b/drivers/soc/renesas/Makefile
@@ -31,6 +31,8 @@ ifdef CONFIG_SMP
obj-$(CONFIG_ARCH_R9A06G032) += r9a06g032-smp.o
endif

+obj-$(CONFIG_RISCV) += rzfive/
+
# Family
obj-$(CONFIG_RST_RCAR) += rcar-rst.o
obj-$(CONFIG_SYSC_RCAR) += rcar-sysc.o
diff --git a/drivers/soc/renesas/rzfive/Kconfig b/drivers/soc/renesas/rzfive/Kconfig
new file mode 100644
index 000000000000..b6bc00337d99
--- /dev/null
+++ b/drivers/soc/renesas/rzfive/Kconfig
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0
+
+config AX45MP_L2_CACHE
+ bool "Andes Technology AX45MP L2 Cache controller"
+ help
+ Support for the L2 cache controller on Andes Technology AX45MP platforms.
diff --git a/drivers/soc/renesas/rzfive/Makefile b/drivers/soc/renesas/rzfive/Makefile
new file mode 100644
index 000000000000..2012e7fb978d
--- /dev/null
+++ b/drivers/soc/renesas/rzfive/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_AX45MP_L2_CACHE) += ax45mp_cache.o
diff --git a/drivers/soc/renesas/rzfive/ax45mp_cache.c b/drivers/soc/renesas/rzfive/ax45mp_cache.c
new file mode 100644
index 000000000000..d98f71b86b9b
--- /dev/null
+++ b/drivers/soc/renesas/rzfive/ax45mp_cache.c
@@ -0,0 +1,256 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * non-coherent cache functions for Andes AX45MP
+ *
+ * Copyright (C) 2022 Renesas Electronics Corp.
+ */
+
+#include <linux/cacheflush.h>
+#include <linux/cacheinfo.h>
+#include <linux/dma-direction.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+
+#include <asm/cacheflush.h>
+#include <asm/sbi.h>
+
+/* L2 cache registers */
+#define AX45MP_L2C_REG_CTL_OFFSET 0x8
+
+#define AX45MP_L2C_REG_C0_CMD_OFFSET 0x40
+#define AX45MP_L2C_REG_C0_ACC_OFFSET 0x48
+#define AX45MP_L2C_REG_STATUS_OFFSET 0x80
+
+/* D-cache operation */
+#define AX45MP_CCTL_L1D_VA_INVAL 0
+#define AX45MP_CCTL_L1D_VA_WB 1
+
+/* L2 CCTL status */
+#define AX45MP_CCTL_L2_STATUS_IDLE 0
+
+/* L2 CCTL status cores mask */
+#define AX45MP_CCTL_L2_STATUS_C0_MASK 0xf
+
+/* L2 cache operation */
+#define AX45MP_CCTL_L2_PA_INVAL 0x8
+#define AX45MP_CCTL_L2_PA_WB 0x9
+
+#define AX45MP_L2C_REG_PER_CORE_OFFSET 0x10
+#define AX45MP_CCTL_L2_STATUS_PER_CORE_OFFSET 4
+
+#define AX45MP_L2C_REG_CN_CMD_OFFSET(n) \
+ (AX45MP_L2C_REG_C0_CMD_OFFSET + ((n) * AX45MP_L2C_REG_PER_CORE_OFFSET))
+#define AX45MP_L2C_REG_CN_ACC_OFFSET(n) \
+ (AX45MP_L2C_REG_C0_ACC_OFFSET + ((n) * AX45MP_L2C_REG_PER_CORE_OFFSET))
+#define AX45MP_CCTL_L2_STATUS_CN_MASK(n) \
+ (AX45MP_CCTL_L2_STATUS_C0_MASK << ((n) * AX45MP_CCTL_L2_STATUS_PER_CORE_OFFSET))
+
+#define AX45MP_CCTL_REG_UCCTLBEGINADDR_NUM 0x80b
+#define AX45MP_CCTL_REG_UCCTLCOMMAND_NUM 0x80c
+
+#define AX45MP_CACHE_LINE_SIZE 64
+
+struct ax45mp_priv {
+ void __iomem *l2c_base;
+ u32 ax45mp_cache_line_size;
+};
+
+static struct ax45mp_priv *ax45mp_priv;
+static DEFINE_STATIC_KEY_FALSE(ax45mp_l2c_configured);
+
+/* L2 Cache operations */
+static inline uint32_t ax45mp_cpu_l2c_get_cctl_status(void)
+{
+ return readl(ax45mp_priv->l2c_base + AX45MP_L2C_REG_STATUS_OFFSET);
+}
+
+/*
+ * Software trigger CCTL operation (cache maintenance operations) by writing
+ * to ucctlcommand and ucctlbeginaddr registers and write-back an L2 cache
+ * entry.
+ */
+static void ax45mp_cpu_dcache_wb_range(void *start, void *end, int line_size)
+{
+ void __iomem *base = ax45mp_priv->l2c_base;
+ int mhartid = smp_processor_id();
+ unsigned long pa;
+
+ while (end > start) {
+ csr_write(AX45MP_CCTL_REG_UCCTLBEGINADDR_NUM, start);
+ csr_write(AX45MP_CCTL_REG_UCCTLCOMMAND_NUM, AX45MP_CCTL_L1D_VA_WB);
+
+ pa = virt_to_phys(start);
+ writel(pa, base + AX45MP_L2C_REG_CN_ACC_OFFSET(mhartid));
+ writel(AX45MP_CCTL_L2_PA_WB,
+ base + AX45MP_L2C_REG_CN_CMD_OFFSET(mhartid));
+ while ((ax45mp_cpu_l2c_get_cctl_status() &
+ AX45MP_CCTL_L2_STATUS_CN_MASK(mhartid)) !=
+ AX45MP_CCTL_L2_STATUS_IDLE)
+ ;
+
+ start += line_size;
+ }
+}
+
+/*
+ * Software trigger CCTL operation by writing to ucctlcommand and ucctlbeginaddr
+ * registers and invalidate the L2 cache entry.
+ */
+static void ax45mp_cpu_dcache_inval_range(void *start, void *end, int line_size)
+{
+ void __iomem *base = ax45mp_priv->l2c_base;
+ int mhartid = smp_processor_id();
+ unsigned long pa;
+
+ while (end > start) {
+ csr_write(AX45MP_CCTL_REG_UCCTLBEGINADDR_NUM, start);
+ csr_write(AX45MP_CCTL_REG_UCCTLCOMMAND_NUM, AX45MP_CCTL_L1D_VA_INVAL);
+
+ pa = virt_to_phys(start);
+ writel(pa, base + AX45MP_L2C_REG_CN_ACC_OFFSET(mhartid));
+ writel(AX45MP_CCTL_L2_PA_INVAL,
+ base + AX45MP_L2C_REG_CN_CMD_OFFSET(mhartid));
+ while ((ax45mp_cpu_l2c_get_cctl_status() &
+ AX45MP_CCTL_L2_STATUS_CN_MASK(mhartid)) !=
+ AX45MP_CCTL_L2_STATUS_IDLE)
+ ;
+
+ start += line_size;
+ }
+}
+
+static void ax45mp_cpu_dma_inval_range(void *vaddr, size_t size)
+{
+ char cache_buf[2][AX45MP_CACHE_LINE_SIZE];
+ unsigned long start = (unsigned long)vaddr;
+ unsigned long end = start + size;
+ unsigned long old_start = start;
+ unsigned long old_end = end;
+ unsigned long line_size;
+ unsigned long flags;
+
+ if (unlikely(start == end))
+ return;
+
+ line_size = ax45mp_priv->ax45mp_cache_line_size;
+
+ memset(&cache_buf, 0x0, sizeof(cache_buf));
+ start = start & (~(line_size - 1));
+ end = ((end + line_size - 1) & (~(line_size - 1)));
+
+ local_irq_save(flags);
+ if (unlikely(start != old_start))
+ memcpy(&cache_buf[0][0], (void *)start, line_size);
+
+ if (unlikely(end != old_end))
+ memcpy(&cache_buf[1][0], (void *)(old_end & (~(line_size - 1))), line_size);
+
+ ax45mp_cpu_dcache_inval_range(vaddr, (void *)end, line_size);
+
+ if (unlikely(start != old_start))
+ memcpy((void *)start, &cache_buf[0][0], (old_start & (line_size - 1)));
+
+ local_irq_restore(flags);
+}
+
+static void ax45mp_cpu_dma_wb_range(void *vaddr, size_t size)
+{
+ unsigned long start = (unsigned long)vaddr;
+ unsigned long end = start + size;
+ unsigned long line_size;
+ unsigned long flags;
+
+ line_size = ax45mp_priv->ax45mp_cache_line_size;
+ local_irq_save(flags);
+ start = start & (~(line_size - 1));
+ ax45mp_cpu_dcache_wb_range(vaddr, (void *)end, line_size);
+ local_irq_restore(flags);
+}
+
+void ax45mp_no_iocp_cmo(unsigned int cache_size, void *vaddr, size_t size, int dir, int ops)
+{
+ if (ops == NON_COHERENT_DMA_PREP)
+ return;
+
+ if (!static_branch_unlikely(&ax45mp_l2c_configured))
+ return;
+
+ if (ops == NON_COHERENT_SYNC_DMA_FOR_DEVICE) {
+ switch (dir) {
+ case DMA_FROM_DEVICE:
+ ax45mp_cpu_dma_inval_range(vaddr, size);
+ break;
+ case DMA_TO_DEVICE:
+ case DMA_BIDIRECTIONAL:
+ ax45mp_cpu_dma_wb_range(vaddr, size);
+ break;
+ default:
+ break;
+ }
+ return;
+ }
+
+ /* op == NON_COHERENT_SYNC_DMA_FOR_CPU */
+ if (dir == DMA_BIDIRECTIONAL || dir == DMA_FROM_DEVICE)
+ ax45mp_cpu_dma_inval_range(vaddr, size);
+}
+EXPORT_SYMBOL(ax45mp_no_iocp_cmo);
+
+static void ax45mp_configure_l2_cache(struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ struct device *dev = &pdev->dev;
+ int ret;
+
+ ret = of_property_read_u32(np, "cache-line-size", &ax45mp_priv->ax45mp_cache_line_size);
+ if (ret) {
+ dev_err(dev, "Failed to get cache-line-size, defaulting to 64 bytes\n");
+ ax45mp_priv->ax45mp_cache_line_size = AX45MP_CACHE_LINE_SIZE;
+ }
+
+ if (ax45mp_priv->ax45mp_cache_line_size != AX45MP_CACHE_LINE_SIZE) {
+ dev_err(dev, "Expected cache-line-size to be 64 bytes (found:%u). Defaulting to 64 bytes\n",
+ ax45mp_priv->ax45mp_cache_line_size);
+ ax45mp_priv->ax45mp_cache_line_size = AX45MP_CACHE_LINE_SIZE;
+ }
+}
+
+static int ax45mp_l2c_probe(struct platform_device *pdev)
+{
+ ax45mp_priv = devm_kzalloc(&pdev->dev, sizeof(*ax45mp_priv), GFP_KERNEL);
+ if (!ax45mp_priv)
+ return -ENOMEM;
+
+ ax45mp_priv->l2c_base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(ax45mp_priv->l2c_base))
+ return PTR_ERR(ax45mp_priv->l2c_base);
+
+ ax45mp_configure_l2_cache(pdev);
+
+ static_branch_enable(&ax45mp_l2c_configured);
+
+ return 0;
+}
+
+static const struct of_device_id ax45mp_cache_ids[] = {
+ { .compatible = "andestech,ax45mp-cache" },
+ { /* sentinel */ }
+};
+
+static struct platform_driver ax45mp_l2c_driver = {
+ .driver = {
+ .name = "ax45mp-l2c",
+ .of_match_table = ax45mp_cache_ids,
+ },
+ .probe = ax45mp_l2c_probe,
+};
+
+static int __init ax45mp_cache_init(void)
+{
+ return platform_driver_register(&ax45mp_l2c_driver);
+}
+arch_initcall(ax45mp_cache_init);
+
+MODULE_AUTHOR("Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>");
+MODULE_DESCRIPTION("Andes AX45MP L2 cache driver");
+MODULE_LICENSE("GPL");
--
2.25.1
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