BACKPORT: FROMLIST: scsi: ufs: add program_key() variant op

On Snapdragon SoCs, the Linux kernel isn't permitted to directly access
the standard UFS crypto configuration registers.  Instead, programming
and evicting keys must be done through vendor-specific SMC calls.

To support this hardware, add a ->program_key() method to
'struct ufs_hba_variant_ops'.  This allows overriding the UFS standard
key programming procedure.

Link: https://lore.kernel.org/r/20200110061634.46742-5-ebiggers@kernel.org
Bug: 137270441
Bug: 147259927
Change-Id: Ia561d5a51421baaf78de52a1eaec496093a0d0ad
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Satya Tangirala <satyat@google.com>

drivers/scsi/ufs/ufshcd-crypto.c

@@ -118,15 +118,21 @@ static int ufshcd_crypto_cfg_entry_write_key(union ufs_crypto_cfg_entry *cfg,
 	return -EINVAL;
 }
 
-static void ufshcd_program_key(struct ufs_hba *hba,
-			       const union ufs_crypto_cfg_entry *cfg,
-			       int slot)
+static int ufshcd_program_key(struct ufs_hba *hba,
+			      const union ufs_crypto_cfg_entry *cfg, int slot)
 {
 	int i;
 	u32 slot_offset = hba->crypto_cfg_register + slot * sizeof(*cfg);
+	int err;
 
 	pm_runtime_get_sync(hba->dev);
 	ufshcd_hold(hba, false);
+
+	if (hba->vops->program_key) {
+		err = hba->vops->program_key(hba, cfg, slot);
+		goto out;
+	}
+
 	/* Clear the dword 16 */
 	ufshcd_writel(hba, 0, slot_offset + 16 * sizeof(cfg->reg_val[0]));
 	/* Ensure that CFGE is cleared before programming the key */
@@ -146,15 +152,20 @@ static void ufshcd_program_key(struct ufs_hba *hba,
 	ufshcd_writel(hba, le32_to_cpu(cfg->reg_val[16]),
 		      slot_offset + 16 * sizeof(cfg->reg_val[0]));
 	wmb();
+	err = 0;
+out:
 	ufshcd_release(hba);
 	pm_runtime_put_sync(hba->dev);
+	return err;
 }
 
 static void ufshcd_clear_keyslot(struct ufs_hba *hba, int slot)
 {
 	union ufs_crypto_cfg_entry cfg = { 0 };
+	int err;
 
-	ufshcd_program_key(hba, &cfg, slot);
+	err = ufshcd_program_key(hba, &cfg, slot);
+	WARN_ON_ONCE(err);
 }
 
 /* Clear all keyslots at driver init time */
@@ -199,10 +210,11 @@ static int ufshcd_crypto_keyslot_program(struct keyslot_manager *ksm,
 	if (err)
 		return err;
 
-	ufshcd_program_key(hba, &cfg, slot);
+	err = ufshcd_program_key(hba, &cfg, slot);
 
 	memzero_explicit(&cfg, sizeof(cfg));
-	return 0;
+
+	return err;
 }
 
 static int ufshcd_crypto_keyslot_evict(struct keyslot_manager *ksm,

drivers/scsi/ufs/ufshcd.h

@@ -277,6 +277,8 @@ struct ufs_pwr_mode_info {
 	struct ufs_pa_layer_attr info;
 };
 
+union ufs_crypto_cfg_entry;
+
 /**
  * struct ufs_hba_variant_ops - variant specific callbacks
  * @name: variant name
@@ -303,6 +305,7 @@ struct ufs_pwr_mode_info {
  * @resume: called during host controller PM callback
  * @dbg_register_dump: used to dump controller debug information
  * @phy_initialization: used to initialize phys
+ * @program_key: program an inline encryption key into a keyslot
  */
 struct ufs_hba_variant_ops {
 	const char *name;
@@ -331,6 +334,8 @@ struct ufs_hba_variant_ops {
 	int     (*resume)(struct ufs_hba *, enum ufs_pm_op);
 	void	(*dbg_register_dump)(struct ufs_hba *hba);
 	int	(*phy_initialization)(struct ufs_hba *);
+	int	(*program_key)(struct ufs_hba *hba,
+			       const union ufs_crypto_cfg_entry *cfg, int slot);
 };
 
 struct keyslot_mgmt_ll_ops;