Re: [PATCH 16/31] fdt: translate address if #size-cells = <0>

Hi Dario,

On Tue, 25 Aug 2020 at 03:25, Dario Binacchi dariobin@libero.it 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

there is something missing here. Do you have a # at the start of the line?

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>.

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@libero.it Tested-by: Dario Binacchi dariobin@libero.it

---

arch/sandbox/dts/test.dts | 21 +++++++++++ common/fdt_support.c | 10 ++++-- drivers/core/Kconfig | 12 +++++++ drivers/core/fdtaddr.c | 2 +- drivers/core/of_addr.c | 14 +++----- drivers/core/ofnode.c | 11 ++++-- test/dm/test-fdt.c | 73 +++++++++++++++++++++++++++++++++++++-- 7 files changed, 127 insertions(+), 16 deletions(-)

diff --git a/arch/sandbox/dts/test.dts b/arch/sandbox/dts/test.dts index 1d8956abbe..7f5d8f3aeb 100644 --- a/arch/sandbox/dts/test.dts +++ b/arch/sandbox/dts/test.dts @@ -39,6 +39,7 @@ fdt-dummy1 = "/translation-test@8000/dev@1,100"; fdt-dummy2 = "/translation-test@8000/dev@2,200"; fdt-dummy3 = "/translation-test@8000/noxlatebus@3,300/dev@42";

•           fdt-dummy4 = "/translation-test@8000/xlatebus@4,400/devs/dev@19";
            usb0 = &usb_0;
            usb1 = &usb_1;
            usb2 = &usb_2;
  

@@ -977,6 +978,7 @@ 1 0x100 0x9000 0x1000 2 0x200 0xA000 0x1000 3 0x300 0xB000 0x1000

•                     4 0x400 0xC000 0x1000
                     >;
  
            dma-ranges = <0 0x000 0x10000000 0x1000
  

@@ -1013,6 +1015,25 @@ reg = <0x42>; }; };

•           xlatebus@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@19 {
  

•                                   compatible = "denx,u-boot-fdt-dummy";
  

•                                   reg = <0x19>;
  

•                           };
  

•                   };
  

•           };
  

•   };
  
    osd {
  

diff --git a/common/fdt_support.c b/common/fdt_support.c index a565b470f8..402401e073 100644 --- a/common/fdt_support.c +++ b/common/fdt_support.c @@ -1001,8 +1001,14 @@ 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_ADDR_COUNT(na) ((na) > 0 && (na) <= OF_MAX_ADDR_CELLS) +#if defined(CONFIG_OF_TRANSLATE_ZERO_SIZE_CELLS) +#define OF_CHECK_SIZE_COUNT(ns) ((ns) >= 0) +#else +#define OF_CHECK_SIZE_COUNT(ns) ((ns) > 0) +#endif +#define OF_CHECK_COUNTS(na, ns) (OF_CHECK_ADDR_COUNT(na) && \

•                            OF_CHECK_SIZE_COUNT(ns))
  
  

/* Debug utility */ #ifdef DEBUG diff --git a/drivers/core/Kconfig b/drivers/core/Kconfig index 00d1d80dc3..2a683ae404 100644 --- a/drivers/core/Kconfig +++ b/drivers/core/Kconfig @@ -217,6 +217,18 @@ 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..5a9f08aa44 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 (IS_ENABLED(CONFIG_OF_TRANSLATE_ZERO_SIZE_CELLS) || ns) {
  

Here we should check a flag, perhaps in a new gd->dm_flags value, to determine the behaviour. The problem with using a CONFIG here is that you cannot test it without recompiling. Also the code-size difference is negligible.

So you can use the CONFIG to set the flag, perhaps in dm_init(), and add a helper to change the setting, which can be used in tests.

                    /*
                     * 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..ddac5f9a2b 100644 --- a/drivers/core/of_addr.c +++ b/drivers/core/of_addr.c @@ -18,7 +18,11 @@ /* 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) +#if defined(CONFIG_OF_TRANSLATE_ZERO_SIZE_CELLS) +#define OF_CHECK_COUNTS(na, ns) (OF_CHECK_ADDR_COUNT(na) && (ns) >= 0) +#else #define OF_CHECK_COUNTS(na, ns) (OF_CHECK_ADDR_COUNT(na) && (ns) > 0)

This could be changed to have just one #define by bringing the CONFIG into the expression.

+#endif

static struct of_bus *of_match_bus(struct device_node *np);

@@ -162,11 +166,6 @@ 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 +192,8 @@ 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 d02d8d33fe..b5744e86c3 100644 --- a/drivers/core/ofnode.c +++ b/drivers/core/ofnode.c @@ -304,7 +304,10 @@ 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 ||
  

•                (IS_ENABLED(CONFIG_OF_TRANSLATE_ZERO_SIZE_CELLS) &&
  

•                 ns >= 0))) {
                    return of_translate_address(ofnode_to_np(node), prop_val);
            } else {
                    na = of_n_addr_cells(ofnode_to_np(node));
  

@@ -655,8 +658,12 @@ 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 ||
  

•                (IS_ENABLED(CONFIG_OF_TRANSLATE_ZERO_SIZE_CELLS) &&
  

•                 ns >= 0))) {
                    return of_translate_address(np, prop);
  

•           }
            else
                    return of_read_number(prop, na);
    } else {
  

diff --git a/test/dm/test-fdt.c b/test/dm/test-fdt.c index 04802deb7f..30a7a933dd 100644 --- a/test/dm/test-fdt.c +++ b/test/dm/test-fdt.c @@ -581,6 +581,64 @@ 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; @@ -599,10 +657,21 @@ static int dm_test_fdt_translation(struct unit_test_state *uts) ut_asserteq_str("dev@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@42", dev->name);
  

•   ut_asserteq(0x42, dev_read_addr(dev));
  

•   if (!IS_ENABLED(CONFIG_OF_TRANSLATE_ZERO_SIZE_CELLS)) {
  

Here, adjust the flag so you can run both tests one after the other.

•           /* No translation for busses with #size-cells == 0 */
  

•           ut_asserteq(0x42, dev_read_addr(dev));
  

•   } else {
  

•           /* Translation for busses with #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@19", dev->name);
  

•           ut_asserteq(0xC019, dev_read_addr(dev));
  

lower-case hex please

•   }
  
    /* dma address translation */
    ut_assertok(uclass_find_device_by_seq(UCLASS_TEST_DUMMY, 0, true, &dev));
  

-- 2.17.1

Regards, Simon