[U-Boot] [RFC PATCH 07/22] dm: Allow drivers to be marked 'before relocation'

Simon Glass
2014-05-24T21:21:06Z

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>
---

common/board_r.c | 4 ++--
doc/driver-model/README.txt | 23 +++++++++++++++-------
drivers/core/device.c | 6 ++++--
drivers/core/lists.c | 6 +++---
drivers/core/root.c | 11 +++++++----
include/dm/device-internal.h | 6 ++++--
include/dm/device.h | 5 +++++
include/dm/lists.h | 2 +-
include/dm/root.h | 8 ++++++--
test/dm/core.c | 47 ++++++++++++++++++++++++++++++++++----------
test/dm/test-driver.c | 11 +++++++++++
test/dm/test-fdt.c | 20 ++++++++++++++++++-
test/dm/test-main.c | 4 ++--
test/dm/test.dts | 11 +++++++++++
14 files changed, 128 insertions(+), 36 deletions(-)

diff --git a/common/board_r.c b/common/board_r.c
index d1f0aa9..d2a59ee 100644
--- a/common/board_r.c
+++ b/common/board_r.c
@@ -276,13 +276,13 @@ static int initr_dm(void)
debug("dm_init() failed: %d\n", ret);
return ret;
}
- ret = dm_scan_platdata();
+ ret = dm_scan_platdata(false);
if (ret) {
debug("dm_scan_platdata() failed: %d\n", ret);
return ret;
}
#ifdef CONFIG_OF_CONTROL
- ret = dm_scan_fdt(gd->fdt_blob);
+ ret = dm_scan_fdt(gd->fdt_blob, false);
if (ret) {
debug("dm_scan_fdt() failed: %d\n", ret);
return ret;
diff --git a/doc/driver-model/README.txt b/doc/driver-model/README.txt
index e0b395a..deacfe9 100644
--- a/doc/driver-model/README.txt
+++ b/doc/driver-model/README.txt
@@ -332,26 +332,35 @@ dealing with this might not be worth it.
- Implemented a GPIO system, trying to keep it simple

+Pre-Relocation Support
+----------------------
+
+For pre-relocation we simply call the driver model init function. Only
+drivers marked with DM_FLAG_PRE_RELOC or the device tree 'dm,pre-reloc'
+flag are initialised prior to relocation. This helps to reduce the driver
+model overhead.
+
+Then post relocation we throw that away and re-init driver model again.
+For drivers which require some sort of continuity between pre- and
+post-relocation devices, we can provide access to the pre-relocation
+device pointers, but this is not currently implemented (the root device
+pointer is saved but not made available).
+
+
Things to punt for later
------------------------

- SPL support - this will have to be present before many drivers can be
converted, but it seems like we can add it once we are happy with the
core implementation.
-- Pre-relocation support - similar story

-That is not to say that no thinking has gone into these - in fact there
+That is not to say that no thinking has gone into this - in fact there
is quite a lot there. However, getting these right is non-trivial and
there is a high cost associated with going down the wrong path.

For SPL, it may be possible to fit in a simplified driver model with only
bind and probe methods, to reduce size.

-For pre-relocation we can simply call the driver model init function. Then
-post relocation we throw that away and re-init driver model again. For drivers
-which require some sort of continuity between pre- and post-relocation
-devices, we can provide access to the pre-relocation device pointers.
-
Uclasses are statically numbered at compile time. It would be possible to
change this to dynamic numbering, but then we would require some sort of
lookup service, perhaps searching by name. This is slightly less efficient
diff --git a/drivers/core/device.c b/drivers/core/device.c
index 55ba281..2c2634e 100644
--- a/drivers/core/device.c
+++ b/drivers/core/device.c
@@ -129,14 +129,16 @@ fail_bind:
return ret;
}

-int device_bind_by_name(struct device *parent, const struct driver_info *info,
- struct device **devp)
+int device_bind_by_name(struct device *parent, bool pre_reloc_only,
+ const struct driver_info *info, struct device **devp)
{
struct driver *drv;

drv = lists_driver_lookup_name(info->name);
if (!drv)
return -ENOENT;
+ if (pre_reloc_only && !(drv->flags & DM_FLAG_PRE_RELOC))
+ return -EPERM;

return device_bind(parent, drv, info->name, (void *)info->platdata,
-1, devp);
diff --git a/drivers/core/lists.c b/drivers/core/lists.c
index 6a53362..9e38993 100644
--- a/drivers/core/lists.c
+++ b/drivers/core/lists.c
@@ -61,7 +61,7 @@ struct uclass_driver *lists_uclass_lookup(enum uclass_id id)
return NULL;
}

-int lists_bind_drivers(struct device *parent)
+int lists_bind_drivers(struct device *parent, bool pre_reloc_only)
{
struct driver_info *info =
ll_entry_start(struct driver_info, driver_info);
@@ -72,8 +72,8 @@ int lists_bind_drivers(struct device *parent)
int ret;

for (entry = info; entry != info + n_ents; entry++) {
- ret = device_bind_by_name(parent, entry, &dev);
- if (ret) {
+ ret = device_bind_by_name(parent, pre_reloc_only, entry, &dev);
+ if (ret && ret != -EPERM) {
dm_warn("No match for driver '%s'\n", entry->name);
if (!result || ret != -ENOENT)
result = ret;
diff --git a/drivers/core/root.c b/drivers/core/root.c
index 4873e7b..83299f7 100644
--- a/drivers/core/root.c
+++ b/drivers/core/root.c
@@ -45,7 +45,7 @@ int dm_init(void)
}
INIT_LIST_HEAD(&DM_UCLASS_ROOT());

- ret = device_bind_by_name(NULL, &root_info, &DM_ROOT());
+ ret = device_bind_by_name(NULL, false, &root_info, &DM_ROOT());
if (ret)
return ret;
ret = device_probe(DM_ROOT());
@@ -63,11 +63,11 @@ int dm_uninit(void)
return 0;
}

-int dm_scan_platdata(void)
+int dm_scan_platdata(bool pre_reloc_only)
{
int ret;

- ret = lists_bind_drivers(DM_ROOT());
+ ret = lists_bind_drivers(DM_ROOT(), pre_reloc_only);
if (ret == -ENOENT) {
dm_warn("Some drivers were not found\n");
ret = 0;
@@ -79,7 +79,7 @@ int dm_scan_platdata(void)
}

#ifdef CONFIG_OF_CONTROL
-int dm_scan_fdt(const void *blob)
+int dm_scan_fdt(const void *blob, bool pre_reloc_only)
{
int offset = 0;
int ret = 0, err;
@@ -88,6 +88,9 @@ int dm_scan_fdt(const void *blob)
do {
offset = fdt_next_node(blob, offset, &depth);
if (offset > 0 && depth == 1) {
+ if (pre_reloc_only &&
+ !fdt_getprop(blob, offset, "dm,pre-reloc", NULL))
+ continue;
err = lists_bind_fdt(gd->dm_root, blob, offset);
if (err && !ret)
ret = err;
diff --git a/include/dm/device-internal.h b/include/dm/device-internal.h
index e95b7a9..fde67bb 100644
--- a/include/dm/device-internal.h
+++ b/include/dm/device-internal.h
@@ -45,12 +45,14 @@ int device_bind(struct device *parent, struct driver *drv,
* tree.
*
* @parent: Pointer to device's parent
+ * @pre_reloc_only: If true, bind the driver only if its DM_INIT_F flag is set.
+ * If false bind the driver always.
* @info: Name and platdata for this device
* @devp: Returns a pointer to the bound device
* @return 0 if OK, -ve on error
*/
-int device_bind_by_name(struct device *parent, const struct driver_info *info,
- struct device **devp);
+int device_bind_by_name(struct device *parent, bool pre_reloc_only,
+ const struct driver_info *info, struct device **devp);

/**
* device_probe() - Probe a device, activating it
diff --git a/include/dm/device.h b/include/dm/device.h
index b048b66..32650fd 100644
--- a/include/dm/device.h
+++ b/include/dm/device.h
@@ -23,6 +23,9 @@ struct driver_info;
/* DM is responsible for allocating and freeing platdata */
#define DM_FLAG_ALLOC_PDATA (1 << 1)

+/* DM should init this device prior to relocation */
+#define DM_FLAG_PRE_RELOC (1 << 2)
+
/**
* struct device - An instance of a driver
*
@@ -117,6 +120,7 @@ struct device_id {
* ops: Driver-specific operations. This is typically a list of function
* pointers defined by the driver, to implement driver functions required by
* the uclass.
+ * @flags: driver flags - see DM_FLAGS_...
*/
struct driver {
char *name;
@@ -130,6 +134,7 @@ struct driver {
int priv_auto_alloc_size;
int platdata_auto_alloc_size;
const void *ops; /* driver-specific operations */
+ uint32_t flags;
};

/* Declare a new U-Boot driver */
diff --git a/include/dm/lists.h b/include/dm/lists.h
index d0b720b..13e025e 100644
--- a/include/dm/lists.h
+++ b/include/dm/lists.h
@@ -42,7 +42,7 @@ struct uclass_driver *lists_uclass_lookup(enum uclass_id id);
* @early_only: If true, bind only drivers with the DM_INIT_F flag. If false
* bind all drivers.
*/
-int lists_bind_drivers(struct device *parent);
+int lists_bind_drivers(struct device *parent, bool pre_reloc_only);

/**
* lists_bind_fdt() - bind a device tree node
diff --git a/include/dm/root.h b/include/dm/root.h
index 1631d5d..30ebe6c 100644
--- a/include/dm/root.h
+++ b/include/dm/root.h
@@ -26,9 +26,11 @@ struct device *dm_root(void);
*
* This scans all available platdata and creates drivers for each
*
+ * @pre_reloc_only: If true, bind only drivers with the DM_FLAG_PRE_RELOC
+ * flag. If false bind all drivers.
* @return 0 if OK, -ve on error
*/
-int dm_scan_platdata(void);
+int dm_scan_platdata(bool pre_reloc_only);

/**
* dm_scan_fdt() - Scan the device tree and bind drivers
@@ -36,9 +38,11 @@ int dm_scan_platdata(void);
* This scans the device tree and creates a driver for each node
*
* @blob: Pointer to device tree blob
+ * @pre_reloc_only: If true, bind only drivers with the DM_FLAG_PRE_RELOC
+ * flag. If false bind all drivers.
* @return 0 if OK, -ve on error
*/
-int dm_scan_fdt(const void *blob);
+int dm_scan_fdt(const void *blob, bool pre_reloc_only);

/**
* dm_init() - Initialise Driver Model structures
diff --git a/test/dm/core.c b/test/dm/core.c
index a889fad..63bb561 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 device *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 device *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 +553,19 @@ static int dm_test_children(struct dm_test_state *dms)
return 0;
}
DM_TEST(dm_test_children, 0);
+
+static int dm_test_pre_reloc(struct dm_test_state *dms)
+{
+ struct device *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 c4be8a1..e7fb199 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 e1d982f..d6f5bb8 100644
--- a/test/dm/test-fdt.c
+++ b/test/dm/test-fdt.c
@@ -99,7 +99,7 @@ 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);
@@ -142,3 +142,21 @@ 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 828ed46..49805eb 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 ec5364f..b2eaddd 100644
--- a/test/dm/test.dts
+++ b/test/dm/test.dts
@@ -6,10 +6,21 @@
#address-cells = <1>;
#size-cells = <0>;

+ alias {
+ console = <&uart0>;
+ };
+
+ uart0: serial {
+ compatible = "sandbox,serial";
+ dm,pre-reloc;
+ //text-colour = "cyan";
+ };
+
a-test {
reg = <0>;
compatible = "denx,u-boot-fdt-test";
ping-add = <0>;
+ dm,pre-reloc;
};

junk {
--
1.9.1.423.g4596e3a