> From: Simon Glass <s...@chromium.org>
> 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 <kette...@openbsd.org>
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 <dm/uclass.h>
#include <dm/uclass-internal.h>
#include <dm/util.h>
+#include <iommu.h>
#include <linux/err.h>
#include <linux/list.h>
#include <power-domain.h>
@@ -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 0000000000..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 0000000000..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 0000000000..ff8c5fa62c
--- /dev/null
+++ b/drivers/iommu/apple_dart.c
@@ -0,0 +1,59 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2021 Mark Kettenis <kette...@openbsd.org>
+ */
+
+#include <common.h>
+#include <cpu_func.h>
+#include <dm.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
+
+static int apple_dart_probe(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));
+ }
+ }
+
+ 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_IOMMU,
+ .of_match = apple_dart_ids,
+ .probe = apple_dart_probe
+};
diff --git a/drivers/iommu/iommu-uclass.c b/drivers/iommu/iommu-uclass.c
new file mode 100644
index 0000000000..5c55df3066
--- /dev/null
+++ b/drivers/iommu/iommu-uclass.c
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2021 Mark Kettenis <kette...@openbsd.org>
+ */
+
+#define LOG_CATEGORY UCLASS_IOMMU
+
+#include <common.h>
+#include <dm.h>
+
+#if (CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA))
+int dev_iommu_probe(struct udevice *dev)
+{
+ struct ofnode_phandle_args args;
+ struct udevice *dev_iommu;
+ int i, count, ret = 0;
+
+ count = dev_count_phandle_with_args(dev, "iommus",
+ "#iommu-cells", 0);
+ for (i = 0; i < count; i++) {
+ ret = dev_read_phandle_with_args(dev, "iommus",
+ "#iommu-cells", 0, i, &args);
+ if (ret) {
+ debug("%s: dev_read_phandle_with_args failed: %d\n",
+ __func__, ret);
+ return ret;
+ }
+
+ ret = uclass_get_device_by_ofnode(UCLASS_IOMMU, args.node,
+ &dev_iommu);
+ if (ret) {
+ debug("%s: uclass_get_device_by_ofnode failed: %d\n",
+ __func__, ret);
+ return ret;
+ }
+ }
+
+ return 0;
+}
+#endif
+
+UCLASS_DRIVER(iommu) = {
+ .id = UCLASS_IOMMU,
+ .name = "iommu",
+};
diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
index e7edd409f3..56aa981613 100644
--- a/include/dm/uclass-id.h
+++ b/include/dm/uclass-id.h
@@ -61,6 +61,7 @@ enum uclass_id {
UCLASS_I2C_MUX, /* I2C multiplexer */
UCLASS_I2S, /* I2S bus */
UCLASS_IDE, /* IDE device */
+ UCLASS_IOMMU, /* IOMMU */
UCLASS_IRQ, /* Interrupt controller */
UCLASS_KEYBOARD, /* Keyboard input device */
UCLASS_LED, /* Light-emitting diode (LED) */
