[RFC PATCH 4/5] scsi: ufs: add program_key() variant op

Eric Biggers
2020-01-10T06:18:32Z

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.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
drivers/scsi/ufs/ufshcd-crypto.c | 24 ++++++++++++++++++------
drivers/scsi/ufs/ufshcd.h | 5 +++++
2 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd-crypto.c b/drivers/scsi/ufs/ufshcd-crypto.c
index 2c34beb47f8e0..4b9e4d5770643 100644
--- a/drivers/scsi/ufs/ufshcd-crypto.c
+++ b/drivers/scsi/ufs/ufshcd-crypto.c
@@ -117,15 +117,21 @@ 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 */
@@ -145,15 +151,20 @@ 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 */
@@ -198,10 +209,11 @@ 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,
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index b6f0d08a98a8b..cd0969b93d070 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -280,6 +280,8 @@ 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
@@ -307,6 +309,7 @@ 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 an inline encryption key into a keyslot
*/
struct ufs_hba_variant_ops {
const char *name;
@@ -336,6 +339,8 @@ struct ufs_hba_variant_ops {
void (*dbg_register_dump)(struct ufs_hba *hba);
int (*phy_initialization)(struct ufs_hba *);
void (*device_reset)(struct ufs_hba *hba);
+ int (*program_key)(struct ufs_hba *hba,
+ const union ufs_crypto_cfg_entry *cfg, int slot);
};

/* clock gating state */
--
2.24.1