Re: [PATCH 3/5] misc: Add Apple DART driver
Hi Mark,
On Sun, 26 Sept 2021 at 14:53, Mark Kettenis wrote:
>
> > From: Simon Glass
> > Date: Mon, 20 Sep 2021 19:11:25 -0600
>
> Hi Simon,
>
> > [..]
> >
> > > > > +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() ?
> > >
> > > Well, I need to make sure that this happens before other drivers get
> > > probed (in particular the xhci-dwc3 driver). Is there a better
> > > mechanism to achieve that?
> >
> > If those drivers have something in the DT indicating that they need
> > this, then you can add a uclass_get_device_by_phandle() in those
> > drivers.
>
> Yes, there is an "iommus" property that points at the IOMMU. This is
> a standard property and I think it would make sense to have the core
> device probing code handle it in a way similar to how "power-domains"
> is handled. That way we don't have to add IOMMU hooks into each and
> every driver.
OK.
>
> > If not, then you can probe all the DART devices with uclass_probe_all().
> >
> > Having said that, I see you are using UCLASS_MISC. I suspect this
> > should have its own UCLASS_IOMMU.
>
> So here is a proof-of-concept diff to add UCLASS_IOMMU. This
> deliberately does not yet introduce driver ops yet; coming up with
> something sensible there needs a bit more thought. For USB support
> all I need is for the probe function to put the IOMMU in bypass mode,
> so that is what's implemented here.
>
> Does this look reasonable? I'll split this up eventually into a
> commit that adds UCLASS_IOMMU and a commit that adds the apple_dart
> driver.
Yes from a quick look. Remember for the IOMMU uclass to add a sandbox
test, even though for now it will only probe the driver since there
are no ops.
Also you don't need the #if in iommu-uclass.c as the linked will
garbage-collect it.
Regards,
Simon
Re: [PATCH 3/5] misc: Add Apple DART driver
> From: Simon Glass
> Date: Mon, 20 Sep 2021 19:11:25 -0600
Hi Simon,
> [..]
>
> > > > +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() ?
> >
> > Well, I need to make sure that this happens before other drivers get
> > probed (in particular the xhci-dwc3 driver). Is there a better
> > mechanism to achieve that?
>
> If those drivers have something in the DT indicating that they need
> this, then you can add a uclass_get_device_by_phandle() in those
> drivers.
Yes, there is an "iommus" property that points at the IOMMU. This is
a standard property and I think it would make sense to have the core
device probing code handle it in a way similar to how "power-domains"
is handled. That way we don't have to add IOMMU hooks into each and
every driver.
> If not, then you can probe all the DART devices with uclass_probe_all().
>
> Having said that, I see you are using UCLASS_MISC. I suspect this
> should have its own UCLASS_IOMMU.
So here is a proof-of-concept diff to add UCLASS_IOMMU. This
deliberately does not yet introduce driver ops yet; coming up with
something sensible there needs a bit more thought. For USB support
all I need is for the probe function to put the IOMMU in bypass mode,
so that is what's implemented here.
Does this look reasonable? I'll split this up eventually into a
commit that adds UCLASS_IOMMU and a commit that adds the apple_dart
driver.
commit 606979a32d8e0d19ee45df97ad6855c24e27e5ad
Author: Mark Kettenis
Date: Sun Sep 26 22:35:30 2021 +0200
iommu: Proof of concept
diff --git a/drivers/Kconfig b/drivers/Kconfig
index 417d6f88c2..b26ca8cf70 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -50,6 +50,8 @@ source "drivers/i2c/Kconfig"
source "drivers/input/Kconfig"
+source "drivers/iommu/Kconfig"
+
source "drivers/led/Kconfig"
source "drivers/mailbox/Kconfig"
diff --git a/drivers/Makefile b/drivers/Makefile
index fd218c9056..166aeb9817 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -109,6 +109,7 @@ obj-y += mtd/
obj-y += pwm/
obj-y += reset/
obj-y += input/
+obj-y += iommu/
# SOC specific infrastructure drivers.
obj-y += smem/
obj-y += thermal/
diff --git a/drivers/core/device.c b/drivers/core/device.c
index 29668f6fb3..5f480ad443 100644
--- a/drivers/core/device.c
+++ b/drivers/core/device.c
@@ -28,6 +28,7 @@
#include
#include
#include
+#include
#include
#include
#include
@@ -543,6 +544,13 @@ int device_probe(struct udevice *dev)
goto fail;
}
+ if (CONFIG_IS_ENABLED(IOMMU) && dev->parent &&
+ (device_get_uclass_id(dev) != UCLASS_IOMMU)) {
+ ret = dev_iommu_probe(dev);
+ if (ret)
+ goto fail;
+ }
+
ret = device_get_dma_constraints(dev);
if (ret)
goto fail;
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
new file mode 100644
index 00..d0638140af
--- /dev/null
+++ b/drivers/iommu/Kconfig
@@ -0,0 +1,20 @@
+#
+# IOMMU devices
+#
+
+menu "IOMMU device drivers"
+
+config IOMMU
+ bool "Enable Driver Model for IOMMU drivers"
+ depends on DM
+ help
+ Enable driver model for IOMMU devices.
+
+config APPLE_DART
+ bool "Apple DART support"
+ depends on IOMMU && ARCH_APPLE
+ default y
+ help
+ Enable support for the DART on Apple SoCs.
+
+endmenu
diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile
new file mode 100644
index 00..8a50e3aba8
--- /dev/null
+++ b/drivers/iommu/Makefile
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0+
+
+obj-$(CONFIG_IOMMU) += iommu-uclass.o
+
+obj-$(CONFIG_APPLE_DART) += apple_dart.o
diff --git a/drivers/iommu/apple_dart.c b/drivers/iommu/apple_dart.c
new file mode 100644
index 00..ff8c5fa62c
--- /dev/null
+++ b/drivers/iommu/apple_dart.c
@@ -0,0 +1,59 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2021 Mark Kettenis
+ */
+
+#include
+#include
+#include
+#include
+
+#define DART_PARAMS2 0x0004
+#define DART_PARAMS2_BYPASS_SUPPORT BIT(0)
+#define DART_TLB_OP0x0020
+#define DART_TLB_OP_OPMASK(0xfff << 20)
+#define DART_TLB_OP_FLUSH (0x001 << 20)
Re: [PATCH 3/5] misc: Add Apple DART driver
On Mon, 20 Sept 2021 at 19:11, Simon Glass wrote: > > Hi Mark, > > On Mon, 20 Sept 2021 at 02:33, Mark Kettenis wrote: > > > > > From: Simon Glass > > > Date: Sun, 19 Sep 2021 21:16:00 -0600 > > > > > > Hi Mark, > > > > > > On Sat, 18 Sept 2021 at 07:55, Mark Kettenis 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 > > > > --- > > > > 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 > > > > > Tested on: Macbook Air M1 Tested-by: Simon Glass
Re: [PATCH 3/5] misc: Add Apple DART driver
Hi Mark,
On Mon, 20 Sept 2021 at 02:33, Mark Kettenis wrote:
>
> > From: Simon Glass
> > Date: Sun, 19 Sep 2021 21:16:00 -0600
> >
> > Hi Mark,
> >
> > On Sat, 18 Sept 2021 at 07:55, Mark Kettenis 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
> > > ---
> > > 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
> > >
[..]
> > > +
> > > +struct apple_dart_priv {
> >
> > How about s/apple_dart/dart/ ?
> >
> > It makes the code easier to read.
>
> I think using apple_dart_ consistently as a prefix makes more sense.
OK I don't mind too much. I just prefer shorter code and sometimes
people use globally unique things in drivers when it really doesn't
help anything.
>
> > > + 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?
>
> Not really since the intent is that these variables specify a global
> "window" that is mapped 1:1 into all the DARTs.
So there are multiple DART devices? In that can you could store this
info in a priv struct attached to the uclass.
[..]
> > > +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() ?
>
> Well, I need to make sure that this happens before other drivers get
> probed (in particular the xhci-dwc3 driver). Is there a better
> mechanism to achieve that?
If those drivers have something in the DT indicating that they need
this, then you can add a uclass_get_device_by_phandle() in those
drivers.
If not, then you can probe all the DART devices with uclass_probe_all().
Having said that, I see you are using UCLASS_MISC. I suspect this
should have its own UCLASS_IOMMU.
[..]
> >
> > > + 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 ?
>
> Not sure if we know the exact meaning of those bits yet. But there is
> a Linux driver now, so maybe I need to look at it again.
Oh well, a comment that we don't know is fine, too. People can fix it
later if it becomes known.
[..]
Regards,
Simon
Re: [PATCH 3/5] misc: Add Apple DART driver
> From: Simon Glass
> Date: Sun, 19 Sep 2021 21:16:00 -0600
>
> Hi Mark,
>
> On Sat, 18 Sept 2021 at 07:55, Mark Kettenis 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
> > ---
> > 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?
Sure. The DART is what we usually call an IOMMU.
> > +
> > 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 00..f619a624d0
> > --- /dev/null
> > +++ b/drivers/misc/apple_dart.c
> > @@ -0,0 +1,171 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * Copyright (C) 2021 Mark Kettenis
> > + */
> > +
> > +#include
> > +#include
> > +#include
> > +#include
> > +#include
> > +#include
> > +
> > +#define DART_PARAMS2 0x0004
> > +#define DART_PARAMS2_BYPASS_SUPPORT BIT(0)
> > +#define DART_TLB_OP0x0020
> > +#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_SIDMASK0x0034
> > +#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.
I think using apple_dart_ consistently as a prefix makes more sense.
> > + 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?
Not really since the intent is that these variables specify a global
"window" that is mapped 1:1 into all the DARTs.
> > +
> > +static void apple_dart_flush_tlb(struct apple_dart_priv *priv)
>
> comments on these functions
>
> > +{
> > + u32 status;
> > +
> > + writel(0x, 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, >clks);
> > + if (ret == -ENOSYS || ret == -ENOENT)
>
> Does -ENOSYS not indicate an error? If it doesn't, I think a comment
> would help here.
So we just learned that what we previously considered to be clocks are
really better modelled as power domains. So this code will go away.
> > + return 0;
> > + if
Re: [PATCH 3/5] misc: Add Apple DART driver
Hi Mark,
On Sat, 18 Sept 2021 at 07:55, Mark Kettenis 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
> ---
> 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 00..f619a624d0
> --- /dev/null
> +++ b/drivers/misc/apple_dart.c
> @@ -0,0 +1,171 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (C) 2021 Mark Kettenis
> + */
> +
> +#include
> +#include
> +#include
> +#include
> +#include
> +#include
> +
> +#define DART_PARAMS2 0x0004
> +#define DART_PARAMS2_BYPASS_SUPPORT BIT(0)
> +#define DART_TLB_OP0x0020
> +#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_SIDMASK0x0034
> +#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(0x, 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, >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(>clks);
> + if (ret) {
> + clk_release_bulk(>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 +
