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mach-snapdragon: support parsing memory info from external FDT

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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>
Link: https://lore.kernel.org/r/20250123-qcom-parse-memory-updates-v3-1-c5332b81ea9f@samcday.com
Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>
This commit is contained in:
Sam Day
2025-01-23 12:12:14 +00:00
committed by Caleb Connolly
parent 2babb61428
commit 11ff5a57e2
1 changed files with 63 additions and 30 deletions
Download Patch File Download Diff File Expand all files Collapse all files

93
arch/arm/mach-snapdragon/board.c
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@@ -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)