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cxl/acpi: Make the XOR calculations available for testing 

In preparation for adding a test module that can exercise the address
translation functions performed by the CXL Driver, refactor the XOR
implementation like this:

- Extract the core calculation into a standalone helper function,
- Export the new function for use by test module cxl_translate only,
- Enhance the parameter validation since this new function will be
  called from a test module with no guarantee of valid parameters,
- Move the define of struct cxl_cxims_data to cxl.h so the test module
  can build xormaps.

Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Signed-off-by: Alison Schofield <alison.schofield@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
This commit is contained in:
Alison Schofield 2025-10-14 01:24:31 -07:00 committed by Dave Jiang
parent b78b9e7b79
commit 4fe516d2ad
2 changed files with 43 additions and 11 deletions
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41
drivers/cxl/acpi.c
View File

@ -11,25 +11,36 @@
#include "cxlpci.h"
#include "cxl.h"
struct cxl_cxims_data {
int nr_maps;
u64 xormaps[] __counted_by(nr_maps);
};
static const guid_t acpi_cxl_qtg_id_guid =
GUID_INIT(0xF365F9A6, 0xA7DE, 0x4071,
0xA6, 0x6A, 0xB4, 0x0C, 0x0B, 0x4F, 0x8E, 0x52);
static u64 cxl_apply_xor_maps(struct cxl_root_decoder *cxlrd, u64 addr)
#define HBIW_TO_NR_MAPS_SIZE (CXL_DECODER_MAX_INTERLEAVE + 1)
static const int hbiw_to_nr_maps[HBIW_TO_NR_MAPS_SIZE] = {
[1] = 0, [2] = 1, [3] = 0, [4] = 2, [6] = 1, [8] = 3, [12] = 2, [16] = 4
};
static const int valid_hbiw[] = { 1, 2, 3, 4, 6, 8, 12, 16 };
u64 cxl_do_xormap_calc(struct cxl_cxims_data *cximsd, u64 addr, int hbiw)
{
struct cxl_cxims_data *cximsd = cxlrd->platform_data;
int hbiw = cxlrd->cxlsd.nr_targets;
int nr_maps_to_apply = -1;
u64 val;
int pos;
/* No xormaps for host bridge interleave ways of 1 or 3 */
if (hbiw == 1 || hbiw == 3)
return addr;
/*
* Strictly validate hbiw since this function is used for testing and
* that nullifies any expectation of trusted parameters from the CXL
* Region Driver.
*/
for (int i = 0; i < ARRAY_SIZE(valid_hbiw); i++) {
if (valid_hbiw[i] == hbiw) {
nr_maps_to_apply = hbiw_to_nr_maps[hbiw];
break;
}
}
if (nr_maps_to_apply == -1 || nr_maps_to_apply > cximsd->nr_maps)
return ULLONG_MAX;
/*
* In regions using XOR interleave arithmetic the CXL HPA may not
@ -60,6 +71,14 @@ static u64 cxl_apply_xor_maps(struct cxl_root_decoder *cxlrd, u64 addr)
return addr;
}
EXPORT_SYMBOL_FOR_MODULES(cxl_do_xormap_calc, "cxl_translate");
static u64 cxl_apply_xor_maps(struct cxl_root_decoder *cxlrd, u64 addr)
{
struct cxl_cxims_data *cximsd = cxlrd->platform_data;
return cxl_do_xormap_calc(cximsd, addr, cxlrd->cxlsd.nr_targets);
}
struct cxl_cxims_context {
struct device *dev;

13
drivers/cxl/cxl.h
View File

@ -743,6 +743,19 @@ int cxl_validate_translation_params(u8 eiw, u16 eig, int pos);
u64 cxl_calculate_hpa_offset(u64 dpa_offset, int pos, u8 eiw, u16 eig);
u64 cxl_calculate_dpa_offset(u64 hpa_offset, u8 eiw, u16 eig);
int cxl_calculate_position(u64 hpa_offset, u8 eiw, u16 eig);
struct cxl_cxims_data {
int nr_maps;
u64 xormaps[] __counted_by(nr_maps);
};
#if IS_ENABLED(CONFIG_CXL_ACPI)
u64 cxl_do_xormap_calc(struct cxl_cxims_data *cximsd, u64 addr, int hbiw);
#else
static inline u64 cxl_do_xormap_calc(struct cxl_cxims_data *cximsd, u64 addr, int hbiw)
{
return ULLONG_MAX;
}
#endif
int cxl_num_decoders_committed(struct cxl_port *port);
bool is_cxl_port(const struct device *dev);