Hi Mark, On Sat, 18 Sept 2021 at 07:55, Mark Kettenis <kette...@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 <kette...@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_APPLE > + default y > + help > + Enable 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 <kette...@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