[PATCH v6 17/28] fdt: translate address if #size-cells = <0>
Heinrich Schuchardt
xypron.glpk at gmx.de
Sun Nov 22 20:22:42 CET 2020
On 11/22/20 5:11 PM, Dario Binacchi wrote:
> The __of_translate_address routine translates an address from the
> device tree into a CPU physical address. A note in the description of
> the routine explains that the crossing of any level with
> #size-cells = <0> is to be considered an error not by specification but
> since inherited from IBM. This does not happen for Texas Instruments, or
> at least for the beaglebone device tree. Without this patch, in fact,
> the translation into physical addresses of the registers contained in the
> am33xx-clocks.dtsi nodes would not be possible. They all have a parent
> with #size-cells = <0>.
>
> The CONFIG_OF_TRANSLATE_ZERO_SIZE_CELLS symbol makes translation
> possible even in the case of crossing levels with #size-cells = <0>.
Dear Dario,
Thanks for addressing the incorrect assumption in function
__of_translate_address().
The chapter "2.3.6 reg" of "Devicetree Specification, Release v0.3"
has this sentence:
"If the parent node specifies a value of 0 for #size-cells, the length
field in the value of reg shall be omitted."
What I do not understand yet is why we should have a configuration
option for something that is explicitely required by the device-tree
specification.
Best regards
Heinrich
>
> The patch acts conservatively on address translation, except for
> removing a check within the of_translate_one function in the
> drivers/core/of_addr.c file:
>
> +
> ranges = of_get_property(parent, rprop, &rlen);
> - if (ranges == NULL && !of_empty_ranges_quirk(parent)) {
> - debug("no ranges; cannot translate\n");
> - return 1;
> - }
> if (ranges == NULL || rlen == 0) {
> offset = of_read_number(addr, na);
> memset(addr, 0, pna * 4);
> debug("empty ranges; 1:1 translation\n");
>
> There are two reasons:
> 1 The function of_empty_ranges_quirk always returns false, invalidating
> the following if statement in case of null ranges. Therefore one of
> the two checks is useless.
>
> 2 The implementation of the of_translate_one function found in the
> common/fdt_support.c file has removed this check while keeping the one
> about the 1:1 translation.
>
> The patch adds a test and modifies a check for the correctness of an
> address in the case of enabling translation also for zero size cells.
> The added test checks translations of addresses generated by nodes of
> a device tree similar to those you can find in the files am33xx.dtsi
> and am33xx-clocks.dtsi for which the patch was created.
>
> The patch was also tested on a beaglebone black board. The addresses
> generated for the registers of the loaded drivers are those specified
> by the AM335x reference manual.
>
> Signed-off-by: Dario Binacchi <dariobin at libero.it>
> Tested-by: Dario Binacchi <dariobin at libero.it>
> Reviewed-by: Simon Glass <sjg at chromium.org>
>
> ---
>
> (no changes since v4)
>
> Changes in v4:
> - Add Sphinx documentation for dm_flags.
> - Convert GD_DM_FLG_* to enum.
> - Include device_compat.h header in test/dm/test-fdt.c for dev_xxx macros.
>
> Changes in v3:
> - Comment dm_flags field in the global_data structure.
>
> Changes in v2:
> - Fix a missing line in the commit message.
> - Add dm_flags to global_data structure and GD_DM_FLG_SIZE_CELLS_0 macro
> to test without recompiling.
> - Update the OF_CHECK_COUNTS macro in order to have just one
> #define by bringing the GD_DM_FLG_SIZE_CELLS_0 into the expression.
> - Lower-case the 0xC019 hex number.
>
> arch/sandbox/dts/test.dts | 21 ++++++++++
> common/fdt_support.c | 6 ++-
> drivers/core/Kconfig | 12 ++++++
> drivers/core/fdtaddr.c | 2 +-
> drivers/core/of_addr.c | 14 ++-----
> drivers/core/ofnode.c | 7 +++-
> drivers/core/root.c | 3 ++
> include/asm-generic/global_data.h | 18 ++++++++
> test/dm/test-fdt.c | 69 ++++++++++++++++++++++++++++++-
> 9 files changed, 136 insertions(+), 16 deletions(-)
>
> diff --git a/arch/sandbox/dts/test.dts b/arch/sandbox/dts/test.dts
> index f3b766271d..637d79caf7 100644
> --- a/arch/sandbox/dts/test.dts
> +++ b/arch/sandbox/dts/test.dts
> @@ -41,6 +41,7 @@
> fdt-dummy1 = "/translation-test at 8000/dev at 1,100";
> fdt-dummy2 = "/translation-test at 8000/dev at 2,200";
> fdt-dummy3 = "/translation-test at 8000/noxlatebus at 3,300/dev at 42";
> + fdt-dummy4 = "/translation-test at 8000/xlatebus at 4,400/devs/dev at 19";
> usb0 = &usb_0;
> usb1 = &usb_1;
> usb2 = &usb_2;
> @@ -1061,6 +1062,7 @@
> 1 0x100 0x9000 0x1000
> 2 0x200 0xA000 0x1000
> 3 0x300 0xB000 0x1000
> + 4 0x400 0xC000 0x1000
> >;
>
> dma-ranges = <0 0x000 0x10000000 0x1000
> @@ -1097,6 +1099,25 @@
> reg = <0x42>;
> };
> };
> +
> + xlatebus at 4,400 {
> + compatible = "sandbox,zero-size-cells-bus";
> + reg = <4 0x400 0x1000>;
> + #address-cells = <1>;
> + #size-cells = <1>;
> + ranges = <0 4 0x400 0x1000>;
> +
> + devs {
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + dev at 19 {
> + compatible = "denx,u-boot-fdt-dummy";
> + reg = <0x19>;
> + };
> + };
> + };
> +
> };
>
> osd {
> diff --git a/common/fdt_support.c b/common/fdt_support.c
> index 5ae75df3c6..c817f994ed 100644
> --- a/common/fdt_support.c
> +++ b/common/fdt_support.c
> @@ -20,6 +20,8 @@
> #include <exports.h>
> #include <fdtdec.h>
>
> +DECLARE_GLOBAL_DATA_PTR;
> +
> /**
> * fdt_getprop_u32_default_node - Return a node's property or a default
> *
> @@ -996,8 +998,8 @@ void fdt_del_node_and_alias(void *blob, const char *alias)
> /* Max address size we deal with */
> #define OF_MAX_ADDR_CELLS 4
> #define OF_BAD_ADDR FDT_ADDR_T_NONE
> -#define OF_CHECK_COUNTS(na, ns) ((na) > 0 && (na) <= OF_MAX_ADDR_CELLS && \
> - (ns) > 0)
> +#define OF_CHECK_COUNTS(na, ns) (((na) > 0 && (na) <= OF_MAX_ADDR_CELLS) && \
> + ((ns) > 0 || (gd->dm_flags & GD_DM_FLG_SIZE_CELLS_0)))
>
> /* Debug utility */
> #ifdef DEBUG
> diff --git a/drivers/core/Kconfig b/drivers/core/Kconfig
> index ffae6f9795..c85a685823 100644
> --- a/drivers/core/Kconfig
> +++ b/drivers/core/Kconfig
> @@ -231,6 +231,18 @@ config OF_TRANSLATE
> used for the address translation. This function is faster and
> smaller in size than fdt_translate_address().
>
> +config OF_TRANSLATE_ZERO_SIZE_CELLS
> + bool "Enable translation for zero size cells"
> + depends on OF_TRANSLATE
> + default n
> + help
> + The routine used to translate an FDT address into a physical CPU
> + address was developed by IBM. It considers that crossing any level
> + with #size-cells = <0> makes translation impossible, even if it is
> + not the way it was specified.
> + Enabling this option makes translation possible even in the case
> + of crossing levels with #size-cells = <0>.
> +
> config SPL_OF_TRANSLATE
> bool "Translate addresses using fdt_translate_address in SPL"
> depends on SPL_DM && SPL_OF_CONTROL
> diff --git a/drivers/core/fdtaddr.c b/drivers/core/fdtaddr.c
> index 8b48aa5bc5..51a0093d65 100644
> --- a/drivers/core/fdtaddr.c
> +++ b/drivers/core/fdtaddr.c
> @@ -49,7 +49,7 @@ fdt_addr_t devfdt_get_addr_index(const struct udevice *dev, int index)
>
> reg += index * (na + ns);
>
> - if (ns) {
> + if (ns || (gd->dm_flags & GD_DM_FLG_SIZE_CELLS_0)) {
> /*
> * Use the full-fledged translate function for complex
> * bus setups.
> diff --git a/drivers/core/of_addr.c b/drivers/core/of_addr.c
> index ca34d84922..a590533c8a 100644
> --- a/drivers/core/of_addr.c
> +++ b/drivers/core/of_addr.c
> @@ -18,7 +18,9 @@
> /* Max address size we deal with */
> #define OF_MAX_ADDR_CELLS 4
> #define OF_CHECK_ADDR_COUNT(na) ((na) > 0 && (na) <= OF_MAX_ADDR_CELLS)
> -#define OF_CHECK_COUNTS(na, ns) (OF_CHECK_ADDR_COUNT(na) && (ns) > 0)
> +#define OF_CHECK_COUNTS(na, ns) (OF_CHECK_ADDR_COUNT(na) && \
> + ((ns) > 0 || \
> + (gd->dm_flags & GD_DM_FLG_SIZE_CELLS_0)))
>
> static struct of_bus *of_match_bus(struct device_node *np);
>
> @@ -162,11 +164,6 @@ const __be32 *of_get_address(const struct device_node *dev, int index,
> }
> EXPORT_SYMBOL(of_get_address);
>
> -static int of_empty_ranges_quirk(const struct device_node *np)
> -{
> - return false;
> -}
> -
> static int of_translate_one(const struct device_node *parent,
> struct of_bus *bus, struct of_bus *pbus,
> __be32 *addr, int na, int ns, int pna,
> @@ -193,11 +190,8 @@ static int of_translate_one(const struct device_node *parent,
> * As far as we know, this damage only exists on Apple machines, so
> * This code is only enabled on powerpc. --gcl
> */
> +
> ranges = of_get_property(parent, rprop, &rlen);
> - if (ranges == NULL && !of_empty_ranges_quirk(parent)) {
> - debug("no ranges; cannot translate\n");
> - return 1;
> - }
> if (ranges == NULL || rlen == 0) {
> offset = of_read_number(addr, na);
> memset(addr, 0, pna * 4);
> diff --git a/drivers/core/ofnode.c b/drivers/core/ofnode.c
> index a68076bf35..2d52eaccb0 100644
> --- a/drivers/core/ofnode.c
> +++ b/drivers/core/ofnode.c
> @@ -304,7 +304,8 @@ fdt_addr_t ofnode_get_addr_size_index(ofnode node, int index, fdt_size_t *size)
>
> ns = of_n_size_cells(ofnode_to_np(node));
>
> - if (IS_ENABLED(CONFIG_OF_TRANSLATE) && ns > 0) {
> + if (IS_ENABLED(CONFIG_OF_TRANSLATE) &&
> + (ns > 0 || (gd->dm_flags & GD_DM_FLG_SIZE_CELLS_0))) {
> return of_translate_address(ofnode_to_np(node), prop_val);
> } else {
> na = of_n_addr_cells(ofnode_to_np(node));
> @@ -678,8 +679,10 @@ fdt_addr_t ofnode_get_addr_size(ofnode node, const char *property,
> ns = of_n_size_cells(np);
> *sizep = of_read_number(prop + na, ns);
>
> - if (CONFIG_IS_ENABLED(OF_TRANSLATE) && ns > 0)
> + if (CONFIG_IS_ENABLED(OF_TRANSLATE) &&
> + (ns > 0 || (gd->dm_flags & GD_DM_FLG_SIZE_CELLS_0))) {
> return of_translate_address(np, prop);
> + }
> else
> return of_read_number(prop, na);
> } else {
> diff --git a/drivers/core/root.c b/drivers/core/root.c
> index 5f10d7a39c..aac1911ecb 100644
> --- a/drivers/core/root.c
> +++ b/drivers/core/root.c
> @@ -132,6 +132,9 @@ int dm_init(bool of_live)
> {
> int ret;
>
> + if (IS_ENABLED(CONFIG_OF_TRANSLATE_ZERO_SIZE_CELLS))
> + gd->dm_flags |= GD_DM_FLG_SIZE_CELLS_0;
> +
> if (gd->dm_root) {
> dm_warn("Virtual root driver already exists!\n");
> return -EINVAL;
> diff --git a/include/asm-generic/global_data.h b/include/asm-generic/global_data.h
> index 87d827d0f4..9beb8be0e8 100644
> --- a/include/asm-generic/global_data.h
> +++ b/include/asm-generic/global_data.h
> @@ -183,6 +183,12 @@ struct global_data {
> struct global_data *new_gd;
>
> #ifdef CONFIG_DM
> + /**
> + * @dm_flags: additional flags for Driver Model
> + *
> + * See &enum gd_dm_flags
> + */
> + unsigned long dm_flags;
> /**
> * @dm_root: root instance for Driver Model
> */
> @@ -549,6 +555,18 @@ enum gd_flags {
> GD_FLG_SMP_READY = 0x40000,
> };
>
> +/**
> + * enum gd_dm_flags - global data flags for Driver Model
> + *
> + * See field dm_flags of &struct global_data.
> + */
> +enum gd_dm_flags {
> + /**
> + * @GD_DM_FLG_SIZE_CELLS_0: Enable #size-cells=<0> translation
> + */
> + GD_DM_FLG_SIZE_CELLS_0 = 0x00001,
> +};
> +
> #endif /* __ASSEMBLY__ */
>
> #endif /* __ASM_GENERIC_GBL_DATA_H */
> diff --git a/test/dm/test-fdt.c b/test/dm/test-fdt.c
> index cc12419ea0..dd18160cbe 100644
> --- a/test/dm/test-fdt.c
> +++ b/test/dm/test-fdt.c
> @@ -5,6 +5,7 @@
>
> #include <common.h>
> #include <dm.h>
> +#include <dm/device_compat.h>
> #include <errno.h>
> #include <fdtdec.h>
> #include <log.h>
> @@ -581,6 +582,64 @@ U_BOOT_DRIVER(fdt_dummy_drv) = {
> .id = UCLASS_TEST_DUMMY,
> };
>
> +static int zero_size_cells_bus_bind(struct udevice *dev)
> +{
> + ofnode child;
> + int err;
> +
> + ofnode_for_each_subnode(child, dev_ofnode(dev)) {
> + if (ofnode_get_property(child, "compatible", NULL))
> + continue;
> +
> + err = device_bind_driver_to_node(dev,
> + "zero_size_cells_bus_child_drv",
> + "zero_size_cells_bus_child",
> + child, NULL);
> + if (err) {
> + dev_err(dev, "%s: failed to bind %s\n", __func__,
> + ofnode_get_name(child));
> + return err;
> + }
> + }
> +
> + return 0;
> +}
> +
> +static const struct udevice_id zero_size_cells_bus_ids[] = {
> + { .compatible = "sandbox,zero-size-cells-bus" },
> + { }
> +};
> +
> +U_BOOT_DRIVER(zero_size_cells_bus) = {
> + .name = "zero_size_cells_bus_drv",
> + .id = UCLASS_TEST_DUMMY,
> + .of_match = zero_size_cells_bus_ids,
> + .bind = zero_size_cells_bus_bind,
> +};
> +
> +static int zero_size_cells_bus_child_bind(struct udevice *dev)
> +{
> + ofnode child;
> + int err;
> +
> + ofnode_for_each_subnode(child, dev_ofnode(dev)) {
> + err = lists_bind_fdt(dev, child, NULL, false);
> + if (err) {
> + dev_err(dev, "%s: lists_bind_fdt, err=%d\n",
> + __func__, err);
> + return err;
> + }
> + }
> +
> + return 0;
> +}
> +
> +U_BOOT_DRIVER(zero_size_cells_bus_child_drv) = {
> + .name = "zero_size_cells_bus_child_drv",
> + .id = UCLASS_TEST_DUMMY,
> + .bind = zero_size_cells_bus_child_bind,
> +};
> +
> static int dm_test_fdt_translation(struct unit_test_state *uts)
> {
> struct udevice *dev;
> @@ -599,11 +658,19 @@ static int dm_test_fdt_translation(struct unit_test_state *uts)
> ut_asserteq_str("dev at 2,200", dev->name);
> ut_asserteq(0xA000, dev_read_addr(dev));
>
> - /* No translation for busses with #size-cells == 0 */
> ut_assertok(uclass_find_device_by_seq(UCLASS_TEST_DUMMY, 3, true, &dev));
> ut_asserteq_str("dev at 42", dev->name);
> + /* No translation for busses with #size-cells == 0 */
> ut_asserteq(0x42, dev_read_addr(dev));
>
> + /* Translation for busses with #size-cells == 0 */
> + gd->dm_flags |= GD_DM_FLG_SIZE_CELLS_0;
> + ut_asserteq(0x8042, dev_read_addr(dev));
> + ut_assertok(uclass_find_device_by_seq(UCLASS_TEST_DUMMY, 4, true, &dev));
> + ut_asserteq_str("dev at 19", dev->name);
> + ut_asserteq(0xc019, dev_read_addr(dev));
> + gd->dm_flags &= ~GD_DM_FLG_SIZE_CELLS_0;
> +
> /* dma address translation */
> ut_assertok(uclass_find_device_by_seq(UCLASS_TEST_DUMMY, 0, true, &dev));
> dma_addr[0] = cpu_to_be32(0);
>
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