qcom_parse_memory is updated to return a -ENODATA error if the passed FDT does not contain a /memory node, or that node is incomplete (size=0)

board_fdt_blob_setup first tries to call qcom_parse_memory with the internal FDT (if present+valid). If that fails, it tries again with the external FDT (again, if present+valid).

When booting with an internal FDT from upstream, it's likely that this change results in a slight performance hit, since virtually all upstream qcom DTs lack a fully specified memory node. The impact should be negligible, though.

qcom_parse_memory was given a detailed docstring adapted from Caleb's original commit message that introduced the function.

Reviewed-by: Caleb Connolly caleb.connolly@linaro.org Signed-off-by: Sam Day me@samcday.com --- Changes in v3: - Dropped first patch as it's already been pulled into upstream - Changed -ENODATA check in qcom_parse_memory per Caleb's advice in v2 - Link to v2: https://lore.kernel.org/r/20250122-qcom-parse-memory-updates-v2-0-98dfcac821...

Changes in v2: - Update qcom_parse_memory to return -ENODATA if provided FDT lacks valid /memory node - Reworked board_fdt_blob_setup logic to always try qcom_parse_memory on internal FDT, falling back to external if needed - Link to v1: https://lore.kernel.org/r/20250120-qcom-parse-memory-updates-v1-0-54a7f0550c... --- arch/arm/mach-snapdragon/board.c | 93 +++++++++++++++++++++++++++------------- 1 file changed, 63 insertions(+), 30 deletions(-)

diff --git a/arch/arm/mach-snapdragon/board.c b/arch/arm/mach-snapdragon/board.c index 2ef936aab757c7045729a2dd91944f4f9bff917e..e87551784b8d7afb4186533d43b8bddacba9faec 100644 --- a/arch/arm/mach-snapdragon/board.c +++ b/arch/arm/mach-snapdragon/board.c @@ -88,7 +88,29 @@ int dram_init_banksize(void) return 0; }

-static void qcom_parse_memory(const void *fdt) +/** + * The generic memory parsing code in U-Boot lacks a few things that we + * need on Qualcomm: + * + * 1. It sets gd->ram_size and gd->ram_base to represent a single memory block + * 2. setup_dest_addr() later relocates U-Boot to ram_base + ram_size, the end + * of that first memory block. + * + * This results in all memory beyond U-Boot being unusable in Linux when booting + * with EFI. + * + * Since the ranges in the memory node may be out of order, the only way for us + * to correctly determine the relocation address for U-Boot is to parse all + * memory regions and find the highest valid address. + * + * We can't use fdtdec_setup_memory_banksize() since it stores the result in + * gd->bd, which is not yet allocated. + * + * @fdt: FDT blob to parse /memory node from + * + * Return: 0 on success or -ENODATA if /memory node is missing or incomplete + */ +static int qcom_parse_memory(const void *fdt) { int offset; const fdt64_t *memory; @@ -97,16 +119,12 @@ static void qcom_parse_memory(const void *fdt) int i, j, banks;

offset = fdt_path_offset(fdt, "/memory"); - if (offset < 0) { - log_err("No memory node found in device tree!\n"); - return; - } + if (offset < 0) + return -ENODATA;

memory = fdt_getprop(fdt, offset, "reg", &memsize); - if (!memory) { - log_err("No memory configuration was provided by the previous bootloader!\n"); - return; - } + if (!memory) + return -ENODATA;

banks = min(memsize / (2 * sizeof(u64)), (ulong)CONFIG_NR_DRAM_BANKS);

@@ -119,7 +137,6 @@ static void qcom_parse_memory(const void *fdt) for (i = 0, j = 0; i < banks * 2; i += 2, j++) { prevbl_ddr_banks[j].start = get_unaligned_be64(&memory[i]); prevbl_ddr_banks[j].size = get_unaligned_be64(&memory[i + 1]); - /* SM8650 boards sometimes have empty regions! */ if (!prevbl_ddr_banks[j].size) { j--; continue; @@ -127,13 +144,16 @@ static void qcom_parse_memory(const void *fdt) ram_end = max(ram_end, prevbl_ddr_banks[j].start + prevbl_ddr_banks[j].size); }

+ if (!banks || !prevbl_ddr_banks[0].size) + return -ENODATA; + /* Sort our RAM banks -_- */ qsort(prevbl_ddr_banks, banks, sizeof(prevbl_ddr_banks[0]), ddr_bank_cmp);

gd->ram_base = prevbl_ddr_banks[0].start; gd->ram_size = ram_end - gd->ram_base; - debug("ram_base = %#011lx, ram_size = %#011llx, ram_end = %#011llx\n", - gd->ram_base, gd->ram_size, ram_end); + + return 0; }

static void show_psci_version(void) @@ -153,13 +173,14 @@ static void show_psci_version(void) */ int board_fdt_blob_setup(void **fdtp) { - struct fdt_header *fdt; + struct fdt_header *external_fdt, *internal_fdt; bool internal_valid, external_valid; - int ret = 0; + int ret = -ENODATA;

- fdt = (struct fdt_header *)get_prev_bl_fdt_addr(); - external_valid = fdt && !fdt_check_header(fdt); - internal_valid = !fdt_check_header(*fdtp); + internal_fdt = (struct fdt_header *)*fdtp; + external_fdt = (struct fdt_header *)get_prev_bl_fdt_addr(); + external_valid = external_fdt && !fdt_check_header(external_fdt); + internal_valid = !fdt_check_header(internal_fdt);

/* * There is no point returning an error here, U-Boot can't do anything useful in this situation. @@ -167,24 +188,36 @@ int board_fdt_blob_setup(void **fdtp) */ if (!internal_valid && !external_valid) panic("Internal FDT is invalid and no external FDT was provided! (fdt=%#llx)\n", - (phys_addr_t)fdt); + (phys_addr_t)external_fdt); + + /* Prefer memory information from internal DT if it's present */ + if (internal_valid) + ret = qcom_parse_memory(internal_fdt); + + if (ret < 0 && external_valid) { + /* No internal FDT or it lacks a proper /memory node. + * The previous bootloader handed us something, let's try that. + */ + if (internal_valid) + debug("No memory info in internal FDT, falling back to external\n"); + + ret = qcom_parse_memory(external_fdt); + } + + if (ret < 0) + panic("No valid memory ranges found!\n"); + + debug("ram_base = %#011lx, ram_size = %#011llx\n", + gd->ram_base, gd->ram_size);

if (internal_valid) { debug("Using built in FDT\n"); - ret = -EEXIST; - } else { - debug("Using external FDT\n"); - /* So we can use it before returning */ - *fdtp = fdt; + return -EEXIST; }

- /* - * Parse the /memory node while we're here, - * this makes it easy to do other things early. - */ - qcom_parse_memory(*fdtp); - - return ret; + debug("Using external FDT\n"); + *fdtp = external_fdt; + return 0; }

void reset_cpu(void)

--- base-commit: 2eed5a1ff36217372e19f7513bd07077fc76718a change-id: 20250120-qcom-parse-memory-updates-96ffe248cdf1

Best regards,