dm: cache: add the pl310 cache controller driver

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.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>

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

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

drivers/cache/cache-l2x0.c

@@ -0,0 +1,76 @@
+// 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_and_init(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_and_init(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,
+};