crypto: caam - enable instantiation of all RNG4 state handles

RNG4 block contains multiple (i.e. 2) state handles that can be
initialized. This patch adds the necessary code for detecting
which of the two state handles has been instantiated by another
piece of software e.g. u-boot and instantiate the other one (or
both if none was instantiated). Only the state handle(s)
instantiated by this driver will be deinstantiated when removing
the module.

Signed-off-by: Alex Porosanu <alexandru.porosanu@freescale.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 159 insertions, 47 deletions

diff --git a/drivers/crypto/caam/ctrl.c b/drivers/crypto/caam/ctrl.c
index 29cbec18a3a8..26438cd12685 100644
--- a/drivers/crypto/caam/ctrl.c
+++ b/drivers/crypto/caam/ctrl.c
@@ -17,41 +17,49 @@
  * Descriptor to instantiate RNG State Handle 0 in normal mode and
  * load the JDKEK, TDKEK and TDSK registers
  */
-static void build_instantiation_desc(u32 *desc)
+static void build_instantiation_desc(u32 *desc, int handle, int do_sk)
 {
-        u32 *jump_cmd;
+        u32 *jump_cmd, op_flags;
 
         init_job_desc(desc, 0);
 
+        op_flags = OP_TYPE_CLASS1_ALG | OP_ALG_ALGSEL_RNG |
+                        (handle << OP_ALG_AAI_SHIFT) | OP_ALG_AS_INIT;
+
         /* INIT RNG in non-test mode */
-        append_operation(desc, OP_TYPE_CLASS1_ALG | OP_ALG_ALGSEL_RNG |
-                         OP_ALG_AS_INIT);
+        append_operation(desc, op_flags);
 
-        /* wait for done */
-        jump_cmd = append_jump(desc, JUMP_CLASS_CLASS1);
-        set_jump_tgt_here(desc, jump_cmd);
+        if (!handle && do_sk) {
+                /*
+                 * For SH0, Secure Keys must be generated as well
+                 */
 
-        /*
-         * load 1 to clear written reg:
-         * resets the done interrupt and returns the RNG to idle.
-         */
-        append_load_imm_u32(desc, 1, LDST_SRCDST_WORD_CLRW);
+                /* wait for done */
+                jump_cmd = append_jump(desc, JUMP_CLASS_CLASS1);
+                set_jump_tgt_here(desc, jump_cmd);
 
-        /* generate secure keys (non-test) */
-        append_operation(desc, OP_TYPE_CLASS1_ALG | OP_ALG_ALGSEL_RNG |
-                         OP_ALG_AAI_RNG4_SK);
+                /*
+                 * load 1 to clear written reg:
+                 * resets the done interrrupt and returns the RNG to idle.
+                 */
+                append_load_imm_u32(desc, 1, LDST_SRCDST_WORD_CLRW);
+
+                /* Initialize State Handle  */
+                append_operation(desc, OP_TYPE_CLASS1_ALG | OP_ALG_ALGSEL_RNG |
+                                 OP_ALG_AAI_RNG4_SK);
+        }
 
         append_jump(desc, JUMP_CLASS_CLASS1 | JUMP_TYPE_HALT);
 }
 
 /* Descriptor for deinstantiation of State Handle 0 of the RNG block. */
-static void build_deinstantiation_desc(u32 *desc)
+static void build_deinstantiation_desc(u32 *desc, int handle)
 {
         init_job_desc(desc, 0);
 
         /* Uninstantiate State Handle 0 */
         append_operation(desc, OP_TYPE_CLASS1_ALG | OP_ALG_ALGSEL_RNG |
-                         OP_ALG_AS_INITFINAL);
+                         (handle << OP_ALG_AAI_SHIFT) | OP_ALG_AS_INITFINAL);
 
         append_jump(desc, JUMP_CLASS_CLASS1 | JUMP_TYPE_HALT);
 }
@@ -60,11 +68,14 @@ static void build_deinstantiation_desc(u32 *desc)
  * run_descriptor_deco0 - runs a descriptor on DECO0, under direct control of
  *                        the software (no JR/QI used).
  * @ctrldev - pointer to device
+ * @status - descriptor status, after being run
+ *
  * Return: - 0 if no error occurred
  *         - -ENODEV if the DECO couldn't be acquired
  *         - -EAGAIN if an error occurred while executing the descriptor
  */
-static inline int run_descriptor_deco0(struct device *ctrldev, u32 *desc)
+static inline int run_descriptor_deco0(struct device *ctrldev, u32 *desc,
+                                        u32 *status)
 {
         struct caam_drv_private *ctrlpriv = dev_get_drvdata(ctrldev);
         struct caam_full __iomem *topregs;
@@ -113,6 +124,9 @@ static inline int run_descriptor_deco0(struct device *ctrldev, u32 *desc)
                 cpu_relax();
         } while ((deco_dbg_reg & DESC_DBG_DECO_STAT_VALID) && --timeout);
 
+        *status = rd_reg32(&topregs->deco.op_status_hi) &
+                  DECO_OP_STATUS_HI_ERR_MASK;
+
         /* Mark the DECO as free */
         clrbits32(&topregs->ctrl.deco_rq, DECORR_RQD0ENABLE);
 
@@ -126,6 +140,14 @@ static inline int run_descriptor_deco0(struct device *ctrldev, u32 *desc)
  * instantiate_rng - builds and executes a descriptor on DECO0,
  *                   which initializes the RNG block.
  * @ctrldev - pointer to device
+ * @state_handle_mask - bitmask containing the instantiation status
+ *                      for the RNG4 state handles which exist in
+ *                      the RNG4 block: 1 if it's been instantiated
+ *                      by an external entry, 0 otherwise.
+ * @gen_sk  - generate data to be loaded into the JDKEK, TDKEK and TDSK;
+ *            Caution: this can be done only once; if the keys need to be
+ *            regenerated, a POR is required
+ *
  * Return: - 0 if no error occurred
  *         - -ENOMEM if there isn't enough memory to allocate the descriptor
  *         - -ENODEV if DECO0 couldn't be acquired
@@ -133,19 +155,56 @@ static inline int run_descriptor_deco0(struct device *ctrldev, u32 *desc)
  *            f.i. there was a RNG hardware error due to not "good enough"
  *            entropy being aquired.
  */
-static int instantiate_rng(struct device *ctrldev)
+static int instantiate_rng(struct device *ctrldev, int state_handle_mask,
+                           int gen_sk)
 {
-        u32 *desc;
-        int ret = 0;
+        struct caam_drv_private *ctrlpriv = dev_get_drvdata(ctrldev);
+        struct caam_full __iomem *topregs;
+        struct rng4tst __iomem *r4tst;
+        u32 *desc, status, rdsta_val;
+        int ret = 0, sh_idx;
+
+        topregs = (struct caam_full __iomem *)ctrlpriv->ctrl;
+        r4tst = &topregs->ctrl.r4tst[0];
 
         desc = kmalloc(CAAM_CMD_SZ * 7, GFP_KERNEL);
         if (!desc)
                 return -ENOMEM;
-        /* Create the descriptor for instantiating RNG State Handle 0 */
-        build_instantiation_desc(desc);
 
-        /* Try to run it through DECO0 */
-        ret = run_descriptor_deco0(ctrldev, desc);
+        for (sh_idx = 0; sh_idx < RNG4_MAX_HANDLES; sh_idx++) {
+                /*
+                 * If the corresponding bit is set, this state handle
+                 * was initialized by somebody else, so it's left alone.
+                 */
+                if ((1 << sh_idx) & state_handle_mask)
+                        continue;
+
+                /* Create the descriptor for instantiating RNG State Handle */
+                build_instantiation_desc(desc, sh_idx, gen_sk);
+
+                /* Try to run it through DECO0 */
+                ret = run_descriptor_deco0(ctrldev, desc, &status);
+
+                /*
+                 * If ret is not 0, or descriptor status is not 0, then
+                 * something went wrong. No need to try the next state
+                 * handle (if available), bail out here.
+                 * Also, if for some reason, the State Handle didn't get
+                 * instantiated although the descriptor has finished
+                 * without any error (HW optimizations for later
+                 * CAAM eras), then try again.
+                 */
+                rdsta_val =
+                        rd_reg32(&topregs->ctrl.r4tst[0].rdsta) & RDSTA_IFMASK;
+                if (status || !(rdsta_val & (1 << sh_idx)))
+                        ret = -EAGAIN;
+                if (ret)
+                        break;
+
+                dev_info(ctrldev, "Instantiated RNG4 SH%d\n", sh_idx);
+                /* Clear the contents before recreating the descriptor */
+                memset(desc, 0x00, CAAM_CMD_SZ * 7);
+        }
 
         kfree(desc);
 
@@ -156,29 +215,49 @@ static int instantiate_rng(struct device *ctrldev)
  * deinstantiate_rng - builds and executes a descriptor on DECO0,
  *                     which deinitializes the RNG block.
  * @ctrldev - pointer to device
+ * @state_handle_mask - bitmask containing the instantiation status
+ *                      for the RNG4 state handles which exist in
+ *                      the RNG4 block: 1 if it's been instantiated
  *
  * Return: - 0 if no error occurred
  *         - -ENOMEM if there isn't enough memory to allocate the descriptor
  *         - -ENODEV if DECO0 couldn't be acquired
  *         - -EAGAIN if an error occurred when executing the descriptor
  */
-static int deinstantiate_rng(struct device *ctrldev)
+static int deinstantiate_rng(struct device *ctrldev, int state_handle_mask)
 {
-        u32 *desc;
-        int i, ret = 0;
+        u32 *desc, status;
+        int sh_idx, ret = 0;
 
         desc = kmalloc(CAAM_CMD_SZ * 3, GFP_KERNEL);
         if (!desc)
                 return -ENOMEM;
 
-        /* Create the descriptor for deinstantating RNG State Handle 0 */
-        build_deinstantiation_desc(desc);
-
-        /* Try to run it through DECO0 */
-        ret = run_descriptor_deco0(ctrldev, desc);
-
-        if (ret)
-                dev_err(ctrldev, "failed to deinstantiate RNG\n");
+        for (sh_idx = 0; sh_idx < RNG4_MAX_HANDLES; sh_idx++) {
+                /*
+                 * If the corresponding bit is set, then it means the state
+                 * handle was initialized by us, and thus it needs to be
+                 * deintialized as well
+                 */
+                if ((1 << sh_idx) & state_handle_mask) {
+                        /*
+                         * Create the descriptor for deinstantating this state
+                         * handle
+                         */
+                        build_deinstantiation_desc(desc, sh_idx);
+
+                        /* Try to run it through DECO0 */
+                        ret = run_descriptor_deco0(ctrldev, desc, &status);
+
+                        if (ret || status) {
+                                dev_err(ctrldev,
+                                        "Failed to deinstantiate RNG4 SH%d\n",
+                                        sh_idx);
+                                break;
+                        }
+                        dev_info(ctrldev, "Deinstantiated RNG4 SH%d\n", sh_idx);
+                }
+        }
 
         kfree(desc);
 
@@ -204,9 +283,9 @@ static int caam_remove(struct platform_device *pdev)
                 irq_dispose_mapping(jrpriv->irq);
         }
 
-        /* De-initialize RNG if it was initialized by this driver. */
-        if (ctrlpriv->rng4_init)
-                deinstantiate_rng(ctrldev);
+        /* De-initialize RNG state handles initialized by this driver. */
+        if (ctrlpriv->rng4_sh_init)
+                deinstantiate_rng(ctrldev, ctrlpriv->rng4_sh_init);
 
         /* Shut down debug views */
 #ifdef CONFIG_DEBUG_FS
@@ -306,7 +385,7 @@ EXPORT_SYMBOL(caam_get_era);
 /* Probe routine for CAAM top (controller) level */
 static int caam_probe(struct platform_device *pdev)
 {
-        int ret, ring, rspec, ent_delay = RTSDCTL_ENT_DLY_MIN;
+        int ret, ring, rspec, gen_sk, ent_delay = RTSDCTL_ENT_DLY_MIN;
         u64 caam_id;
         struct device *dev;
         struct device_node *nprop, *np;
@@ -414,20 +493,53 @@ static int caam_probe(struct platform_device *pdev)
          * If SEC has RNG version >= 4 and RNG state handle has not been
          * already instantiated, do RNG instantiation
          */
-        if ((cha_vid & CHA_ID_RNG_MASK) >> CHA_ID_RNG_SHIFT >= 4 &&
-            !(rd_reg32(&topregs->ctrl.r4tst[0].rdsta) & RDSTA_IF0)) {
+        if ((cha_vid & CHA_ID_RNG_MASK) >> CHA_ID_RNG_SHIFT >= 4) {
+                ctrlpriv->rng4_sh_init =
+                        rd_reg32(&topregs->ctrl.r4tst[0].rdsta);
+                /*
+                 * If the secure keys (TDKEK, JDKEK, TDSK), were already
+                 * generated, signal this to the function that is instantiating
+                 * the state handles. An error would occur if RNG4 attempts
+                 * to regenerate these keys before the next POR.
+                 */
+                gen_sk = ctrlpriv->rng4_sh_init & RDSTA_SKVN ? 0 : 1;
+                ctrlpriv->rng4_sh_init &= RDSTA_IFMASK;
                 do {
-                        kick_trng(pdev, ent_delay);
-                        ret = instantiate_rng(dev);
-                        ent_delay += 400;
+                        int inst_handles =
+                                rd_reg32(&topregs->ctrl.r4tst[0].rdsta) &
+                                                                RDSTA_IFMASK;
+                        /*
+                         * If either SH were instantiated by somebody else
+                         * (e.g. u-boot) then it is assumed that the entropy
+                         * parameters are properly set and thus the function
+                         * setting these (kick_trng(...)) is skipped.
+                         * Also, if a handle was instantiated, do not change
+                         * the TRNG parameters.
+                         */
+                        if (!(ctrlpriv->rng4_sh_init || inst_handles)) {
+                                kick_trng(pdev, ent_delay);
+                                ent_delay += 400;
+                        }
+                        /*
+                         * if instantiate_rng(...) fails, the loop will rerun
+                         * and the kick_trng(...) function will modfiy the
+                         * upper and lower limits of the entropy sampling
+                         * interval, leading to a sucessful initialization of
+                         * the RNG.
+                         */
+                        ret = instantiate_rng(dev, inst_handles,
+                                              gen_sk);
                 } while ((ret == -EAGAIN) && (ent_delay < RTSDCTL_ENT_DLY_MAX));
                 if (ret) {
                         dev_err(dev, "failed to instantiate RNG");
                         caam_remove(pdev);
                         return ret;
                 }
-
-                ctrlpriv->rng4_init = 1;
+                /*
+                 * Set handles init'ed by this module as the complement of the
+                 * already initialized ones
+                 */
+                ctrlpriv->rng4_sh_init = ~ctrlpriv->rng4_sh_init & RDSTA_IFMASK;
 
                 /* Enable RDB bit so that RNG works faster */
                 setbits32(&topregs->ctrl.scfgr, SCFGR_RDBENABLE);