crypto: ccree - check that cryptocell reset completed

In case of driver probe and pm resume we need to check that the cryptocell
hardware reset cycle is completed. during the reset cycle that Cryptocell
provide read only access to the APB interface which allows to verify
through the CC registers that the reset is completed. Until reset
completion we assume that any write/crypto operation is blocked.

Signed-off-by: Ofir Drang <[e-mail]>
Signed-off-by: Herbert Xu <[e-mail]>

drivers/crypto/ccree/cc_driver.c

···
 };
 
 #define CC_NUM_IDRS 4
+#define CC_HW_RESET_LOOP_COUNT 10
 
 /* Note: PIDR3 holds CMOD/Rev so ignored for HW identification purposes */
 static const u32 pidr_0124_offsets[CC_NUM_IDRS] = {
···
 	}
 
 	return IRQ_HANDLED;
+}
+
+bool cc_wait_for_reset_completion(struct cc_drvdata *drvdata)
+{
+	unsigned int val;
+	unsigned int i;
+
+	/* 712/710/63 has no reset completion indication, always return true */
+	if (drvdata->hw_rev <= CC_HW_REV_712)
+		return true;
+
+	for (i = 0; i < CC_HW_RESET_LOOP_COUNT; i++) {
+		/* in cc7x3 NVM_IS_IDLE indicates that CC reset is
+		 *  completed and device is fully functional
+		 */
+		val = cc_ioread(drvdata, CC_REG(NVM_IS_IDLE));
+		if (val & CC_NVM_IS_IDLE_MASK) {
+			/* hw indicate reset completed */
+			return true;
+		}
+		/* allow scheduling other process on the processor */
+		schedule();
+	}
+	/* reset not completed */
+	return false;
 }
 
 int init_cc_regs(struct cc_drvdata *drvdata, bool is_probe)
···
 
 	new_drvdata->sec_disabled = cc_sec_disable;
 
+	/* wait for Crytpcell reset completion */
+	if (!cc_wait_for_reset_completion(new_drvdata)) {
+		dev_err(dev, "Cryptocell reset not completed");
+	}
+
 	if (hw_rev->rev <= CC_HW_REV_712) {
 		/* Verify correct mapping */
 		val = cc_ioread(new_drvdata, new_drvdata->sig_offset);
···
 	if (rc) {
 		dev_err(dev, "Could not register to interrupt %d\n",
 			new_drvdata->irq);
-		return rc;
+		goto post_clk_err;
 	}
 	dev_dbg(dev, "Registered to IRQ: %d\n", new_drvdata->irq);
 

drivers/crypto/ccree/cc_driver.h

···
 
 #define CC_SECURITY_DISABLED_MASK BIT(CC_SECURITY_DISABLED_VALUE_BIT_SHIFT)
 
+#define CC_NVM_IS_IDLE_MASK BIT(CC_NVM_IS_IDLE_VALUE_BIT_SHIFT)
+
 #define AXIM_MON_COMP_VALUE GENMASK(CC_AXIM_MON_COMP_VALUE_BIT_SIZE + \
 				    CC_AXIM_MON_COMP_VALUE_BIT_SHIFT, \
 				    CC_AXIM_MON_COMP_VALUE_BIT_SHIFT)
···
 		__dump_byte_array(name, the_array, size);
 }
 
+bool cc_wait_for_reset_completion(struct cc_drvdata *drvdata);
 int init_cc_regs(struct cc_drvdata *drvdata, bool is_probe);
 void fini_cc_regs(struct cc_drvdata *drvdata);
 int cc_clk_on(struct cc_drvdata *drvdata);

drivers/crypto/ccree/cc_host_regs.h

···
 #define CC_HOST_ICR_DSCRPTR_WATERMARK_QUEUE0_CLEAR_BIT_SIZE	0x1UL
 #define CC_HOST_ICR_AXIM_COMP_INT_CLEAR_BIT_SHIFT	0x17UL
 #define CC_HOST_ICR_AXIM_COMP_INT_CLEAR_BIT_SIZE	0x1UL
+#define CC_NVM_IS_IDLE_REG_OFFSET       0x0A10UL
+#define CC_NVM_IS_IDLE_VALUE_BIT_SHIFT  0x0UL
+#define CC_NVM_IS_IDLE_VALUE_BIT_SIZE   0x1UL
 #define CC_SECURITY_DISABLED_REG_OFFSET		0x0A1CUL
 #define CC_SECURITY_DISABLED_VALUE_BIT_SHIFT	0x0UL
 #define CC_SECURITY_DISABLED_VALUE_BIT_SIZE	0x1UL

drivers/crypto/ccree/cc_pm.c

···
 		dev_err(dev, "failed getting clock back on. We're toast.\n");
 		return rc;
 	}
+	/* wait for Crytpcell reset completion */
+	if (!cc_wait_for_reset_completion(drvdata)) {
+		dev_err(dev, "Cryptocell reset not completed");
+		return -EBUSY;
+	}
 
 	cc_iowrite(drvdata, CC_REG(HOST_POWER_DOWN_EN), POWER_DOWN_DISABLE);
 	rc = init_cc_regs(drvdata, false);