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 / eviction procedure.

Link: https://lore.kernel.org/r/20200710072013.177481-5-ebiggers@kernel.org
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/ufs/ufshcd-crypto.c b/drivers/scsi/ufs/ufshcd-crypto.c
index 98ff87c..d2edbd9 100644 (file)
--- a/drivers/scsi/ufs/ufshcd-crypto.c
+++ b/drivers/scsi/ufs/ufshcd-crypto.c
@@ -17,14 +17,20 @@ static const struct ufs_crypto_alg_entry {
        },
 };
 
-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 = 0;
 
        ufshcd_hold(hba, false);
+
+       if (hba->vops && hba->vops->program_key) {
+               err = hba->vops->program_key(hba, cfg, slot);
+               goto out;
+       }
+
        /* Ensure that CFGE is cleared before programming the key */
        ufshcd_writel(hba, 0, slot_offset + 16 * sizeof(cfg->reg_val[0]));
        for (i = 0; i < 16; i++) {
@@ -37,7 +43,9 @@ static void ufshcd_program_key(struct ufs_hba *hba,
        /* Dword 16 must be written last */
        ufshcd_writel(hba, le32_to_cpu(cfg->reg_val[16]),
                      slot_offset + 16 * sizeof(cfg->reg_val[0]));
+out:
        ufshcd_release(hba);
+       return err;
 }
 
 static int ufshcd_crypto_keyslot_program(struct blk_keyslot_manager *ksm,
@@ -52,6 +60,7 @@ static int ufshcd_crypto_keyslot_program(struct blk_keyslot_manager *ksm,
        int i;
        int cap_idx = -1;
        union ufs_crypto_cfg_entry cfg = { 0 };
+       int err;
 
        BUILD_BUG_ON(UFS_CRYPTO_KEY_SIZE_INVALID != 0);
        for (i = 0; i < hba->crypto_capabilities.num_crypto_cap; i++) {
@@ -79,13 +88,13 @@ static int ufshcd_crypto_keyslot_program(struct blk_keyslot_manager *ksm,
                memcpy(cfg.crypto_key, key->raw, key->size);
        }
 
-       ufshcd_program_key(hba, &cfg, slot);
+       err = ufshcd_program_key(hba, &cfg, slot);
 
        memzero_explicit(&cfg, sizeof(cfg));
-       return 0;
+       return err;
 }
 
-static void ufshcd_clear_keyslot(struct ufs_hba *hba, int slot)
+static int ufshcd_clear_keyslot(struct ufs_hba *hba, int slot)
 {
        /*
         * Clear the crypto cfg on the device. Clearing CFGE
@@ -93,7 +102,7 @@ static void ufshcd_clear_keyslot(struct ufs_hba *hba, int slot)
         */
        union ufs_crypto_cfg_entry cfg = { 0 };
 
-       ufshcd_program_key(hba, &cfg, slot);
+       return ufshcd_program_key(hba, &cfg, slot);
 }
 
 static int ufshcd_crypto_keyslot_evict(struct blk_keyslot_manager *ksm,
@@ -102,9 +111,7 @@ static int ufshcd_crypto_keyslot_evict(struct blk_keyslot_manager *ksm,
 {
        struct ufs_hba *hba = container_of(ksm, struct ufs_hba, ksm);
 
-       ufshcd_clear_keyslot(hba, slot);
-
-       return 0;
+       return ufshcd_clear_keyslot(hba, slot);
 }
 
 bool ufshcd_crypto_enable(struct ufs_hba *hba)

diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index 656c069..b2ef18f 100644 (file)
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -281,6 +281,7 @@ struct ufs_pwr_mode_info {
  * @dbg_register_dump: used to dump controller debug information
  * @phy_initialization: used to initialize phys
  * @device_reset: called to issue a reset pulse on the UFS device
+ * @program_key: program or evict an inline encryption key
  */
 struct ufs_hba_variant_ops {
        const char *name;
@@ -314,6 +315,8 @@ struct ufs_hba_variant_ops {
        void    (*config_scaling_param)(struct ufs_hba *hba,
                                        struct devfreq_dev_profile *profile,
                                        void *data);
+       int     (*program_key)(struct ufs_hba *hba,
+                              const union ufs_crypto_cfg_entry *cfg, int slot);
 };
 
 /* clock gating state  */