[PATCH v6 5/6] cache: Add L2 cache management for Andes AX45MP RISC-V core
Prabhakar
prabhakar.csengg at gmail.com
Fri Jan 6 10:55:25 PST 2023
From: Lad Prabhakar <prabhakar.mahadev-lad.rj at 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 at 58000000 {
compatible = "shared-dma-pool";
reg = <0x0 0x58000000 0x0 0x08000000>;
no-map;
linux,dma-default;
};
};
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj at bp.renesas.com>
---
v5 -> v6
* Moved driver to cache folder
* Switched to new API for CMO
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.
---
drivers/Kconfig | 2 +
drivers/Makefile | 1 +
drivers/cache/Kconfig | 10 ++
drivers/cache/Makefile | 3 +
drivers/cache/ax45mp_cache.c | 279 +++++++++++++++++++++++++++++++++++
5 files changed, 295 insertions(+)
create mode 100644 drivers/cache/Kconfig
create mode 100644 drivers/cache/Makefile
create mode 100644 drivers/cache/ax45mp_cache.c
diff --git a/drivers/Kconfig b/drivers/Kconfig
index 968bd0a6fd78..44abd2cba3a3 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -15,6 +15,8 @@ source "drivers/base/Kconfig"
source "drivers/bus/Kconfig"
+source "drivers/cache/Kconfig"
+
source "drivers/connector/Kconfig"
source "drivers/firmware/Kconfig"
diff --git a/drivers/Makefile b/drivers/Makefile
index bdf1c66141c9..9fc91d2bbe4c 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -6,6 +6,7 @@
# Rewritten to use lists instead of if-statements.
#
+obj-y += cache/
obj-y += irqchip/
obj-y += bus/
diff --git a/drivers/cache/Kconfig b/drivers/cache/Kconfig
new file mode 100644
index 000000000000..5478adff3d88
--- /dev/null
+++ b/drivers/cache/Kconfig
@@ -0,0 +1,10 @@
+# SPDX-License-Identifier: GPL-2.0
+menu "Cache Drivers"
+
+config AX45MP_L2_CACHE
+ bool "Andes Technology AX45MP L2 Cache controller"
+ depends on RISCV && RISCV_DMA_NONCOHERENT
+ help
+ Support for the L2 cache controller on Andes Technology AX45MP platforms.
+
+endmenu
diff --git a/drivers/cache/Makefile b/drivers/cache/Makefile
new file mode 100644
index 000000000000..2012e7fb978d
--- /dev/null
+++ b/drivers/cache/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_AX45MP_L2_CACHE) += ax45mp_cache.o
diff --git a/drivers/cache/ax45mp_cache.c b/drivers/cache/ax45mp_cache.c
new file mode 100644
index 000000000000..556e6875627c
--- /dev/null
+++ b/drivers/cache/ax45mp_cache.c
@@ -0,0 +1,279 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * non-coherent cache functions for Andes AX45MP
+ *
+ * Copyright (C) 2022 Renesas Electronics Corp.
+ */
+
+#include <asm/dma-noncoherent.h>
+#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;
+
+/* 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);
+}
+
+static void ax45mp_no_iocp_cmo(void *vaddr, size_t size,
+ enum dma_data_direction dir,
+ enum dma_noncoherent_ops ops)
+{
+ /* We have nothing to do in case of NON_COHERENT_DMA_PREP */
+ if (ops != NON_COHERENT_SYNC_DMA_FOR_DEVICE &&
+ ops != NON_COHERENT_SYNC_DMA_FOR_CPU)
+ return;
+
+ /*
+ * In case of DMA_FROM_DEVICE invalidate the L2 cache entries and
+ * in case of DMA_TO_DEVICE and DMA_BIDIRECTIONAL write-back an L2
+ * cache entries.
+ */
+ 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;
+ }
+
+ /*
+ * ops == NON_COHERENT_SYNC_DMA_FOR_CPU
+ *
+ * in case of DMA_BIDIRECTIONAL and DMA_FROM_DEVICE invalidate the L2
+ * cache entries.
+ */
+ if (dir == DMA_BIDIRECTIONAL || dir == DMA_FROM_DEVICE)
+ ax45mp_cpu_dma_inval_range(vaddr, size);
+}
+
+static void ax45mp_get_l2_line_size(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)
+{
+ struct riscv_cache_ops ax45mp_cmo_ops;
+
+ /*
+ * riscv_cbom_block_size is set very much earlier so we can
+ * definitely rely on it and only if its being set we continue
+ * further in the probe path.
+ */
+ if (!riscv_cbom_block_size)
+ return 0;
+
+ 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_get_l2_line_size(pdev);
+
+ memset(&ax45mp_cmo_ops, 0x0, sizeof(ax45mp_cmo_ops));
+ ax45mp_cmo_ops.riscv_dma_noncoherent_cmo_ops = &ax45mp_no_iocp_cmo;
+ riscv_noncoherent_register_cache_ops(&ax45mp_cmo_ops);
+
+ 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 at bp.renesas.com>");
+MODULE_DESCRIPTION("Andes AX45MP L2 cache driver");
+MODULE_LICENSE("GPL");
--
2.25.1
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