crypto: ccp - Cleanup sp_dev_master in psp_dev_destroy()

Introduce clear_psp_master_device() to ensure that sp_dev_master gets
properly cleared on the release of a psp device.

Fixes: 2a6170df ("crypto: ccp: Add Platform Security Processor (PSP) device support")
Signed-off-by: John Allen <john.allen@amd.com>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/ccp/psp-dev.c

@@ -215,6 +215,9 @@ void psp_dev_destroy(struct sp_device *sp)
 	tee_dev_destroy(psp);
 
 	sp_free_psp_irq(sp, psp);
+
+	if (sp->clear_psp_master_device)
+		sp->clear_psp_master_device(sp);
 }
 
 void psp_set_sev_irq_handler(struct psp_device *psp, psp_irq_handler_t handler,

drivers/crypto/ccp/sp-dev.h

@@ -90,6 +90,7 @@ struct sp_device {
 	/* get and set master device */
 	struct sp_device*(*get_psp_master_device)(void);
 	void (*set_psp_master_device)(struct sp_device *);
+	void (*clear_psp_master_device)(struct sp_device *);
 
 	bool irq_registered;
 	bool use_tasklet;

drivers/crypto/ccp/sp-pci.c

@@ -146,6 +146,14 @@ static struct sp_device *psp_get_master(void)
 	return sp_dev_master;
 }
 
+static void psp_clear_master(struct sp_device *sp)
+{
+	if (sp == sp_dev_master) {
+		sp_dev_master = NULL;
+		dev_dbg(sp->dev, "Cleared sp_dev_master\n");
+	}
+}
+
 static int sp_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 {
 	struct sp_device *sp;
@@ -206,6 +214,7 @@ static int sp_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	pci_set_master(pdev);
 	sp->set_psp_master_device = psp_set_master;
 	sp->get_psp_master_device = psp_get_master;
+	sp->clear_psp_master_device = psp_clear_master;
 
 	ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(48));
 	if (ret) {