Hi Mark,
On Sat, 18 Sept 2021 at 07:55, Mark Kettenis kettenis@openbsd.org wrote:
The DART is an IOMMU that is used on Apple's M1 SoC. This driver supports the DART in bypass mode as well as in a mode where it creates a 1:1 mapping of a subset of RAM as not all DARTs support bypass mode. The USB3 ports integrated on the SoC use a DART that supports bypass mode. The 1:1 mapping will be used in the future to support other devices such as the PCIe host bridge of the M1 SoC.
Signed-off-by: Mark Kettenis kettenis@openbsd.org
drivers/misc/Kconfig | 7 ++ drivers/misc/Makefile | 1 + drivers/misc/apple_dart.c | 171 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 179 insertions(+) create mode 100644 drivers/misc/apple_dart.c
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig index 997b713221..d70b060e74 100644 --- a/drivers/misc/Kconfig +++ b/drivers/misc/Kconfig @@ -38,6 +38,13 @@ config ALTERA_SYSID Select this to enable a sysid for Altera devices. Please find details on the "Embedded Peripherals IP User Guide" of Altera.
+config APPLE_DART
bool "Apple DART support"depends on MISC && ARCH_APPLEdefault yhelpEnable support for the DART on Apple SoCs.
Should have at least 3 lines. E.g. what does DART stand for, what does it do and what does the driver support?
config ATSHA204A bool "Support for Atmel ATSHA204A module" depends on MISC diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile index b64cd2a4de..f666cd392d 100644 --- a/drivers/misc/Makefile +++ b/drivers/misc/Makefile @@ -29,6 +29,7 @@ endif endif obj-$(CONFIG_ALI152X) += ali512x.o obj-$(CONFIG_ALTERA_SYSID) += altera_sysid.o +obj-$(CONFIG_APPLE_DART) += apple_dart.o obj-$(CONFIG_ATSHA204A) += atsha204a-i2c.o obj-$(CONFIG_CBMEM_CONSOLE) += cbmem_console.o obj-$(CONFIG_DS4510) += ds4510.o diff --git a/drivers/misc/apple_dart.c b/drivers/misc/apple_dart.c new file mode 100644 index 0000000000..f619a624d0 --- /dev/null +++ b/drivers/misc/apple_dart.c @@ -0,0 +1,171 @@ +// SPDX-License-Identifier: GPL-2.0+ +/*
- Copyright (C) 2021 Mark Kettenis kettenis@openbsd.org
- */
+#include <common.h> +#include <clk.h> +#include <cpu_func.h> +#include <dm.h> +#include <mapmem.h> +#include <asm/io.h>
+#define DART_PARAMS2 0x0004 +#define DART_PARAMS2_BYPASS_SUPPORT BIT(0) +#define DART_TLB_OP 0x0020 +#define DART_TLB_OP_OPMASK (0xfff << 20) +#define DART_TLB_OP_FLUSH (0x001 << 20) +#define DART_TLB_OP_BUSY BIT(2) +#define DART_TLB_OP_SIDMASK 0x0034 +#define DART_ERROR_STATUS 0x0040 +#define DART_TCR(sid) (0x0100 + 4 * (sid)) +#define DART_TCR_TRANSLATE_ENABLE BIT(7) +#define DART_TCR_BYPASS_DART BIT(8) +#define DART_TCR_BYPASS_DAPF BIT(12) +#define DART_TTBR(sid, idx) (0x0200 + 16 * (sid) + 4 * (idx)) +#define DART_TTBR_VALID BIT(31) +#define DART_TTBR_SHIFT 12
+struct apple_dart_priv {
How about s/apple_dart/dart/ ?
It makes the code easier to read.
struct clk_bulk clks;void *base;+};
+dma_addr_t apple_dart_bus_start; +phys_addr_t apple_dart_phys_start; +phys_size_t apple_dart_size = SZ_512M;
Try to avoid variables in drivers. Can these go in a priv struct?
+static void apple_dart_flush_tlb(struct apple_dart_priv *priv)
comments on these functions
+{
u32 status;writel(0xffffffff, priv->base + DART_TLB_OP_SIDMASK);writel(DART_TLB_OP_FLUSH, priv->base + DART_TLB_OP);for (;;) {status = readl(priv->base + DART_TLB_OP);if ((status & DART_TLB_OP_OPMASK) == 0)break;if ((status & DART_TLB_OP_BUSY) == 0)break;}+}
+static int apple_dart_clk_init(struct udevice *dev,
struct apple_dart_priv *priv)+{
int ret;ret = clk_get_bulk(dev, &priv->clks);if (ret == -ENOSYS || ret == -ENOENT)
Does -ENOSYS not indicate an error? If it doesn't, I think a comment would help here.
return 0;if (ret)return ret;ret = clk_enable_bulk(&priv->clks);if (ret) {clk_release_bulk(&priv->clks);return ret;}return 0;+}
+static int apple_dart_bind(struct udevice *dev) +{
void *base;int sid, i;base = dev_read_addr_ptr(dev);if (!base)return -EINVAL;u32 params2 = readl(base + DART_PARAMS2);if (params2 & DART_PARAMS2_BYPASS_SUPPORT) {for (sid = 0; sid < 16; sid++) {writel(DART_TCR_BYPASS_DART | DART_TCR_BYPASS_DAPF,base + DART_TCR(sid));for (i = 0; i < 4; i++)writel(0, base + DART_TTBR(sid, i));}}
Not allowed hardware access in bind(). Can this more to probe() ?
return 0;+}
+static int apple_dart_probe(struct udevice *dev) +{
struct apple_dart_priv *priv = dev_get_priv(dev);phys_addr_t phys;u64 *l1, *l2;int sid, i, j;int ret;apple_dart_phys_start = gd->ram_top - apple_dart_size;priv->base = dev_read_addr_ptr(dev);if (!priv->base)return -EINVAL;ret = apple_dart_clk_init(dev, priv);if (ret)return ret;l1 = memalign(SZ_64K, SZ_64K);memset(l1, 0, SZ_64K);i = 0;phys = apple_dart_phys_start;while (phys < apple_dart_phys_start + apple_dart_size) {l2 = memalign(SZ_16K, SZ_16K);
check for error
memset(l2, 0, SZ_16K);for (j = 0; j < 2048; j++) {l2[j] = phys | 0x3;phys += SZ_16K;}flush_dcache_range((unsigned long)l2,(unsigned long)l2 + SZ_16K);l1[i++] = (phys_addr_t)l2 | 0x8 | 0x3;
Do you need the cast? What are the magic numbers here? Can you use an enum/#define ?
}flush_dcache_range((unsigned long)l1, (unsigned long)l1 + SZ_64K);for (sid = 0; sid < 16; sid++) {
comment,...what is this doing?
for (i = 0; i < 4; i++)writel(0, priv->base + DART_TTBR(sid, i));}apple_dart_flush_tlb(priv);for (sid = 0; sid < 16; sid++) {phys = (phys_addr_t)l1;for (i = 0; i < 4; i++) {writel((phys >> DART_TTBR_SHIFT) | DART_TTBR_VALID,priv->base + DART_TTBR(sid, i));phys += SZ_16K;}}apple_dart_flush_tlb(priv);for (sid = 0; sid < 16; sid++)writel(DART_TCR_TRANSLATE_ENABLE, priv->base + DART_TCR(sid));return 0;+}
+static const struct udevice_id apple_dart_ids[] = {
{ .compatible = "apple,t8103-dart" },{ /* sentinel */ }+};
+U_BOOT_DRIVER(apple_dart) = {
.name = "apple_dart",.id = UCLASS_MISC,.of_match = apple_dart_ids,.priv_auto = sizeof(struct apple_dart_priv),.bind = apple_dart_bind,.probe = apple_dart_probe+};
2.33.0
Regards, Simon