Commit a1a6a4cf authored by Luca Coelho's avatar Luca Coelho
Browse files

iwlwifi: pnvm: implement reading PNVM from UEFI 



We now support fetching the PNVM data from a UEFI variable.  Add the
code to read this variable first and use it.  If it's not available,
we fall back to reading the data from the filesystem, as before.

Signed-off-by: default avatarLuca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20210211015026.289084803334.Ie234805047df3be84f4235f9dafaf4cdecf0db9a@changeid


Signed-off-by: default avatarLuca Coelho <luciano.coelho@intel.com>
parent cdda18fb

drivers/net/wireless/intel/iwlwifi/fw/pnvm.c

+90 −1
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ 
#include "fw/api/commands.h"

#include "fw/api/nvm-reg.h"

#include "fw/api/alive.h"

#include <linux/efi.h>



struct iwl_pnvm_section {

	__le32 offset;
@@ -219,6 +220,88 @@ static int iwl_pnvm_parse(struct iwl_trans *trans, const u8 *data, 
	return -ENOENT;

}



/*

 * This is known to be broken on v4.19 and to work on v5.4.  Until we

 * figure out why this is the case and how to make it work, simply

 * disable the feature in old kernels.

 */

#if defined(CONFIG_EFI)



#define IWL_EFI_VAR_GUID EFI_GUID(0x92daaf2f, 0xc02b, 0x455b,	\

				  0xb2, 0xec, 0xf5, 0xa3,	\

				  0x59, 0x4f, 0x4a, 0xea)



#define IWL_UEFI_OEM_PNVM_NAME	L"UefiCnvWlanOemSignedPnvm"



#define IWL_HARDCODED_PNVM_SIZE 4096



struct pnvm_sku_package {

	u8 rev;

	u8 reserved1[3];

	u32 total_size;

	u8 n_skus;

	u8 reserved2[11];

	u8 data[];

};



static int iwl_pnvm_get_from_efi(struct iwl_trans *trans,

				 u8 **data, size_t *len)

{

	struct efivar_entry *pnvm_efivar;

	struct pnvm_sku_package *package;

	unsigned long package_size;

	int err;



	pnvm_efivar = kzalloc(sizeof(*pnvm_efivar), GFP_KERNEL);

	if (!pnvm_efivar)

		return -ENOMEM;



	memcpy(&pnvm_efivar->var.VariableName, IWL_UEFI_OEM_PNVM_NAME,

	       sizeof(IWL_UEFI_OEM_PNVM_NAME));

	pnvm_efivar->var.VendorGuid = IWL_EFI_VAR_GUID;



	/*

	 * TODO: we hardcode a maximum length here, because reading

	 * from the UEFI is not working.  To implement this properly,

	 * we have to call efivar_entry_size().

	 */

	package_size = IWL_HARDCODED_PNVM_SIZE;



	package = kmalloc(package_size, GFP_KERNEL);

	if (!package) {

		err = -ENOMEM;

		goto out;

	}



	err = efivar_entry_get(pnvm_efivar, NULL, &package_size, package);

	if (err) {

		IWL_DEBUG_FW(trans,

			     "PNVM UEFI variable not found %d (len %zd)\n",

			     err, package_size);

		goto out;

	}



	IWL_DEBUG_FW(trans, "Read PNVM fro UEFI with size %zd\n", package_size);



	*data = kmemdup(package->data, *len, GFP_KERNEL);

	if (!*data)

		err = -ENOMEM;

	*len = package_size - sizeof(*package);



out:

	kfree(package);

	kfree(pnvm_efivar);



	return err;

}

#else /* CONFIG_EFI */

static inline int iwl_pnvm_get_from_efi(struct iwl_trans *trans,

					u8 **data, size_t *len)

{

	return -EOPNOTSUPP;

}

#endif /* CONFIG_EFI */



static int iwl_pnvm_get_from_fs(struct iwl_trans *trans, u8 **data, size_t *len)

{

	const struct firmware *pnvm;
@@ -277,7 +360,12 @@ int iwl_pnvm_load(struct iwl_trans *trans, 
		goto skip_parse;

	}



	/* Try to load the PNVM from the filesystem */

	/* First attempt to get the PNVM from BIOS */

	ret = iwl_pnvm_get_from_efi(trans, &data, &len);

	if (!ret)

		goto parse;



	/* If it's not available, try from the filesystem */

	ret = iwl_pnvm_get_from_fs(trans, &data, &len);

	if (ret) {

		/*
@@ -290,6 +378,7 @@ int iwl_pnvm_load(struct iwl_trans *trans, 
		goto skip_parse;

	}



parse:

	iwl_pnvm_parse(trans, data, len);



	kfree(data);