dm: Allow drivers to be marked 'before relocation'

Driver model currently only operates after relocation is complete. In this
state U-Boot typically has a small amount of memory available. In adding
support for driver model prior to relocation we must try to use as little
memory as possible.

In addition, on some machines the memory has not be inited and/or the CPU
is not running at full speed or the data cache is off. These can reduce
execution performance, so the less initialisation that is done before
relocation the better.

An immediately-obvious improvement is to only initialise drivers which are
actually going to be used before relocation. On many boards the only such
driver is a serial UART, so this provides a very large potential benefit.

Allow drivers to mark themselves as 'pre-reloc' which means that they will
be initialised prior to relocation. This can be done either with a driver
flag or with a 'dm,pre-reloc' device tree property.

To support this, the various dm scanning function now take a 'pre_reloc_only'
parameter which indicates that only drivers marked pre-reloc should be
bound.

Signed-off-by: Simon Glass <sjg@chromium.org>

5 files changed, 80 insertions, 13 deletions

diff --git a/test/dm/core.c b/test/dm/core.c
index 8c187806ec..24e0b6b898 100644
--- a/test/dm/core.c
+++ b/test/dm/core.c
@@ -25,6 +25,7 @@ enum {
 	TEST_INTVAL2		= 3,
 	TEST_INTVAL3		= 6,
 	TEST_INTVAL_MANUAL	= 101112,
+	TEST_INTVAL_PRE_RELOC	= 7,
 };
 
 static const struct dm_test_pdata test_pdata[] = {
@@ -37,6 +38,10 @@ static const struct dm_test_pdata test_pdata_manual = {
 	.ping_add		= TEST_INTVAL_MANUAL,
 };
 
+static const struct dm_test_pdata test_pdata_pre_reloc = {
+	.ping_add		= TEST_INTVAL_PRE_RELOC,
+};
+
 U_BOOT_DEVICE(dm_test_info1) = {
 	.name = "test_drv",
 	.platdata = &test_pdata[0],
@@ -57,6 +62,11 @@ static struct driver_info driver_info_manual = {
 	.platdata = &test_pdata_manual,
 };
 
+static struct driver_info driver_info_pre_reloc = {
+	.name = "test_pre_reloc_drv",
+	.platdata = &test_pdata_manual,
+};
+
 /* Test that binding with platdata occurs correctly */
 static int dm_test_autobind(struct dm_test_state *dms)
 {
@@ -71,7 +81,7 @@ static int dm_test_autobind(struct dm_test_state *dms)
 	ut_asserteq(0, list_count_items(&gd->dm_root->child_head));
 	ut_asserteq(0, dm_testdrv_op_count[DM_TEST_OP_POST_BIND]);
 
-	ut_assertok(dm_scan_platdata());
+	ut_assertok(dm_scan_platdata(false));
 
 	/* We should have our test class now at least, plus more children */
 	ut_assert(1 < list_count_items(&gd->uclass_root));
@@ -181,7 +191,7 @@ static int dm_test_lifecycle(struct dm_test_state *dms)
 
 	memcpy(op_count, dm_testdrv_op_count, sizeof(op_count));
 
-	ut_assertok(device_bind_by_name(dms->root, &driver_info_manual,
+	ut_assertok(device_bind_by_name(dms->root, false, &driver_info_manual,
 					&dev));
 	ut_assert(dev);
 	ut_assert(dm_testdrv_op_count[DM_TEST_OP_BIND]
@@ -232,15 +242,15 @@ static int dm_test_ordering(struct dm_test_state *dms)
 	struct udevice *dev, *dev_penultimate, *dev_last, *test_dev;
 	int pingret;
 
-	ut_assertok(device_bind_by_name(dms->root, &driver_info_manual,
+	ut_assertok(device_bind_by_name(dms->root, false, &driver_info_manual,
 					&dev));
 	ut_assert(dev);
 
 	/* Bind two new devices (numbers 4 and 5) */
-	ut_assertok(device_bind_by_name(dms->root, &driver_info_manual,
+	ut_assertok(device_bind_by_name(dms->root, false, &driver_info_manual,
 					&dev_penultimate));
 	ut_assert(dev_penultimate);
-	ut_assertok(device_bind_by_name(dms->root, &driver_info_manual,
+	ut_assertok(device_bind_by_name(dms->root, false, &driver_info_manual,
 					&dev_last));
 	ut_assert(dev_last);
 
@@ -255,7 +265,8 @@ static int dm_test_ordering(struct dm_test_state *dms)
 	ut_assert(dev_last == test_dev);
 
 	/* Add back the original device 3, now in position 5 */
-	ut_assertok(device_bind_by_name(dms->root, &driver_info_manual, &dev));
+	ut_assertok(device_bind_by_name(dms->root, false, &driver_info_manual,
+					&dev));
 	ut_assert(dev);
 
 	/* Try ping */
@@ -375,8 +386,8 @@ static int dm_test_leak(struct dm_test_state *dms)
 		if (!start.uordblks)
 			puts("Warning: Please add '#define DEBUG' to the top of common/dlmalloc.c\n");
 
-		ut_assertok(dm_scan_platdata());
-		ut_assertok(dm_scan_fdt(gd->fdt_blob));
+		ut_assertok(dm_scan_platdata(false));
+		ut_assertok(dm_scan_fdt(gd->fdt_blob, false));
 
 		/* Scanning the uclass is enough to probe all the devices */
 		for (id = UCLASS_ROOT; id < UCLASS_COUNT; id++) {
@@ -444,8 +455,8 @@ static int create_children(struct dm_test_state *dms, struct udevice *parent,
 	for (i = 0; i < count; i++) {
 		struct dm_test_pdata *pdata;
 
-		ut_assertok(device_bind_by_name(parent, &driver_info_manual,
-						&dev));
+		ut_assertok(device_bind_by_name(parent, false,
+						&driver_info_manual, &dev));
 		pdata = calloc(1, sizeof(*pdata));
 		pdata->ping_add = key + i;
 		dev->platdata = pdata;
@@ -542,3 +553,20 @@ static int dm_test_children(struct dm_test_state *dms)
 	return 0;
 }
 DM_TEST(dm_test_children, 0);
+
+/* Test that pre-relocation devices work as expected */
+static int dm_test_pre_reloc(struct dm_test_state *dms)
+{
+	struct udevice *dev;
+
+	/* The normal driver should refuse to bind before relocation */
+	ut_asserteq(-EPERM, device_bind_by_name(dms->root, true,
+						&driver_info_manual, &dev));
+
+	/* But this one is marked pre-reloc */
+	ut_assertok(device_bind_by_name(dms->root, true,
+					&driver_info_pre_reloc, &dev));
+
+	return 0;
+}
+DM_TEST(dm_test_pre_reloc, 0);
diff --git a/test/dm/test-driver.c b/test/dm/test-driver.c
index 0f1a37b36e..bc6a6e721d 100644
--- a/test/dm/test-driver.c
+++ b/test/dm/test-driver.c
@@ -144,3 +144,14 @@ U_BOOT_DRIVER(test_manual_drv) = {
 	.remove	= test_manual_remove,
 	.unbind	= test_manual_unbind,
 };
+
+U_BOOT_DRIVER(test_pre_reloc_drv) = {
+	.name	= "test_pre_reloc_drv",
+	.id	= UCLASS_TEST,
+	.ops	= &test_manual_ops,
+	.bind	= test_manual_bind,
+	.probe	= test_manual_probe,
+	.remove	= test_manual_remove,
+	.unbind	= test_manual_unbind,
+	.flags	= DM_FLAG_PRE_RELOC,
+};
diff --git a/test/dm/test-fdt.c b/test/dm/test-fdt.c
index 0f505373a3..d284f7fa05 100644
--- a/test/dm/test-fdt.c
+++ b/test/dm/test-fdt.c
@@ -100,7 +100,7 @@ static int dm_test_fdt(struct dm_test_state *dms)
 	int ret;
 	int i;
 
-	ret = dm_scan_fdt(gd->fdt_blob);
+	ret = dm_scan_fdt(gd->fdt_blob, false);
 	ut_assert(!ret);
 
 	ret = uclass_get(UCLASS_TEST_FDT, &uc);
@@ -145,3 +145,21 @@ static int dm_test_fdt(struct dm_test_state *dms)
 	return 0;
 }
 DM_TEST(dm_test_fdt, 0);
+
+static int dm_test_fdt_pre_reloc(struct dm_test_state *dms)
+{
+	struct uclass *uc;
+	int ret;
+
+	ret = dm_scan_fdt(gd->fdt_blob, true);
+	ut_assert(!ret);
+
+	ret = uclass_get(UCLASS_TEST_FDT, &uc);
+	ut_assert(!ret);
+
+	/* These is only one pre-reloc device */
+	ut_asserteq(1, list_count_items(&uc->dev_head));
+
+	return 0;
+}
+DM_TEST(dm_test_fdt_pre_reloc, 0);
diff --git a/test/dm/test-main.c b/test/dm/test-main.c
index fbdae688e0..94ce72abfd 100644
--- a/test/dm/test-main.c
+++ b/test/dm/test-main.c
@@ -89,11 +89,11 @@ int dm_test_main(void)
 		ut_assertok(dm_test_init(dms));
 
 		if (test->flags & DM_TESTF_SCAN_PDATA)
-			ut_assertok(dm_scan_platdata());
+			ut_assertok(dm_scan_platdata(false));
 		if (test->flags & DM_TESTF_PROBE_TEST)
 			ut_assertok(do_autoprobe(dms));
 		if (test->flags & DM_TESTF_SCAN_FDT)
-			ut_assertok(dm_scan_fdt(gd->fdt_blob));
+			ut_assertok(dm_scan_fdt(gd->fdt_blob, false));
 
 		if (test->func(dms))
 			break;
diff --git a/test/dm/test.dts b/test/dm/test.dts
index 74d236b495..cd18a3107b 100644
--- a/test/dm/test.dts
+++ b/test/dm/test.dts
@@ -6,11 +6,21 @@
 	#address-cells = <1>;
 	#size-cells = <0>;
 
+	aliases {
+		console = &uart0;
+	};
+
+	uart0: serial {
+		compatible = "sandbox,serial";
+		u-boot,dm-pre-reloc;
+	};
+
 	a-test {
 		reg = <0>;
 		compatible = "denx,u-boot-fdt-test";
 		ping-expect = <0>;
 		ping-add = <0>;
+		u-boot,dm-pre-reloc;
 	};
 
 	junk {