[U-Boot] [PATCHv2 4/6] dm: cache: add the pl310 cache controller driver

[Dinh Nguyen]

Add a PL310 cache controller driver that is usually found on
ARMv7(32-bit) devices. The driver configures the cache settings that can
be found in the device tree files.

This initial revision only configures basic settings(data & instruction
prefetch, shared-override, data & tag latency). I believe these are the
settings that affect performance the most. Comprehensive settings can be
done by the OS.

Signed-off-by: Dinh Nguyen <dingu...@kernel.org>
---
v2: split out patch and address comments from Simon Glass
---
 drivers/cache/Kconfig      |  9 +++++
 drivers/cache/Makefile     |  1 +
 drivers/cache/cache-l2x0.c | 75 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 85 insertions(+)
 create mode 100644 drivers/cache/cache-l2x0.c

diff --git a/drivers/cache/Kconfig b/drivers/cache/Kconfig
index 8b7c9c7f9f..24def7ac0f 100644
--- a/drivers/cache/Kconfig
+++ b/drivers/cache/Kconfig
@@ -13,4 +13,13 @@ config CACHE
          is usually located on the same chip. This uclass can be used for
          configuring settings that be found from a device tree file.
 
+config L2X0_CACHE
+       tristate "PL310 cache driver"
+       select CACHE
+       depends on ARM
+       help
+         This driver is for the PL310 cache controller commonly found on
+         ARMv7(32-bit) devices. The driver configures the cache settings
+         found in the device tree.
+
 endmenu
diff --git a/drivers/cache/Makefile b/drivers/cache/Makefile
index 2ba68060c1..9deb961d91 100644
--- a/drivers/cache/Makefile
+++ b/drivers/cache/Makefile
@@ -1,3 +1,4 @@
 
 obj-$(CONFIG_CACHE) += cache-uclass.o
 obj-$(CONFIG_SANDBOX) += sandbox_cache.o
+obj-$(CONFIG_L2X0_CACHE) += cache-l2x0.o
diff --git a/drivers/cache/cache-l2x0.c b/drivers/cache/cache-l2x0.c
new file mode 100644
index 0000000000..a23a66c4a8
--- /dev/null
+++ b/drivers/cache/cache-l2x0.c
@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 Intel Corporation <www.intel.com>
+ */
+#include <common.h>
+#include <command.h>
+#include <dm.h>
+
+#include <asm/io.h>
+#include <asm/pl310.h>
+
+static void l2c310_of_parse(struct udevice *dev)
+{
+       u32 tag[3] = { 0, 0, 0 };
+       u32 saved_reg, prefetch;
+       struct pl310_regs *regs = (struct pl310_regs *)dev_read_addr(dev);
+
+       /* Disable the L2 Cache */
+       clrbits_le32(&regs->pl310_ctrl, L2X0_CTRL_EN);
+
+       saved_reg = readl(&regs->pl310_aux_ctrl);
+       if (!dev_read_u32(dev, "prefetch-data", &prefetch)) {
+               if (prefetch)
+                       saved_reg |= L310_AUX_CTRL_DATA_PREFETCH_MASK;
+               else
+                       saved_reg &= ~L310_AUX_CTRL_DATA_PREFETCH_MASK;
+       }
+
+       if (!dev_read_u32(dev, "prefetch-instr", &prefetch)) {
+               if (prefetch)
+                       saved_reg |= L310_AUX_CTRL_INST_PREFETCH_MASK;
+               else
+                       saved_reg &= ~L310_AUX_CTRL_INST_PREFETCH_MASK;
+       }
+
+       saved_reg |= dev_read_bool(dev, "arm,shared-override");
+       writel(saved_reg, &regs->pl310_aux_ctrl);
+
+       saved_reg = readl(&regs->pl310_tag_latency_ctrl);
+       if (!dev_read_u32_array(dev, "arm,tag-latency", tag, 3))
+               saved_reg |= L310_LATENCY_CTRL_RD(tag[0] - 1) |
+                            L310_LATENCY_CTRL_WR(tag[1] - 1) |
+                            L310_LATENCY_CTRL_SETUP(tag[2] - 1);
+       writel(saved_reg, &regs->pl310_tag_latency_ctrl);
+
+       saved_reg = readl(&regs->pl310_data_latency_ctrl);
+       if (!dev_read_u32_array(dev, "arm,data-latency", tag, 3))
+               saved_reg |= L310_LATENCY_CTRL_RD(tag[0] - 1) |
+                            L310_LATENCY_CTRL_WR(tag[1] - 1) |
+                            L310_LATENCY_CTRL_SETUP(tag[2] - 1);
+       writel(saved_reg, &regs->pl310_data_latency_ctrl);
+
+       /* Enable the L2 cache */
+       setbits_le32(&regs->pl310_ctrl, L2X0_CTRL_EN);
+}
+
+static int l2x0_probe(struct udevice *dev)
+{
+       l2c310_of_parse(dev);
+       return 0;
+}
+
+
+static const struct udevice_id l2x0_ids[] = {
+       { .compatible = "arm,pl310-cache" },
+       {}
+};
+
+U_BOOT_DRIVER(pl310_cache) = {
+       .name   = "pl310_cache",
+       .id     = UCLASS_CACHE,
+       .of_match = l2x0_ids,
+       .probe  = l2x0_probe,
+       .flags  = DM_FLAG_PRE_RELOC,
+};
-- 
2.20.0

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