1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2020-21 Intel Corporation.
4  */
5 
6 #include "iosm_ipc_pcie.h"
7 #include "iosm_ipc_protocol.h"
8 
9 static void ipc_write_dbell_reg(struct iosm_pcie *ipc_pcie, int irq_n, u32 data)
10 {
11 	void __iomem *write_reg;
12 
13 	/* Select the first doorbell register, which is only currently needed
14 	 * by CP.
15 	 */
16 	write_reg = (void __iomem *)((u8 __iomem *)ipc_pcie->ipc_regs +
17 				     ipc_pcie->doorbell_write +
18 				     (irq_n * ipc_pcie->doorbell_reg_offset));
19 
20 	/* Fire the doorbell irq by writing data on the doorbell write pointer
21 	 * register.
22 	 */
23 	iowrite32(data, write_reg);
24 }
25 
26 void ipc_doorbell_fire(struct iosm_pcie *ipc_pcie, int irq_n, u32 data)
27 {
28 	ipc_write_dbell_reg(ipc_pcie, irq_n, data);
29 }
30 
31 /* Threaded Interrupt handler for MSI interrupts */
32 static irqreturn_t ipc_msi_interrupt(int irq, void *dev_id)
33 {
34 	struct iosm_pcie *ipc_pcie = dev_id;
35 	int instance = irq - ipc_pcie->pci->irq;
36 
37 	/* Shift the MSI irq actions to the IPC tasklet. IRQ_NONE means the
38 	 * irq was not from the IPC device or could not be served.
39 	 */
40 	if (instance >= ipc_pcie->nvec)
41 		return IRQ_NONE;
42 
43 	if (!test_bit(0, &ipc_pcie->suspend))
44 		ipc_imem_irq_process(ipc_pcie->imem, instance);
45 
46 	return IRQ_HANDLED;
47 }
48 
49 void ipc_release_irq(struct iosm_pcie *ipc_pcie)
50 {
51 	struct pci_dev *pdev = ipc_pcie->pci;
52 
53 	if (pdev->msi_enabled) {
54 		while (--ipc_pcie->nvec >= 0)
55 			free_irq(pdev->irq + ipc_pcie->nvec, ipc_pcie);
56 	}
57 	pci_free_irq_vectors(pdev);
58 }
59 
60 int ipc_acquire_irq(struct iosm_pcie *ipc_pcie)
61 {
62 	struct pci_dev *pdev = ipc_pcie->pci;
63 	int i, rc = -EINVAL;
64 
65 	ipc_pcie->nvec = pci_alloc_irq_vectors(pdev, IPC_MSI_VECTORS,
66 					       IPC_MSI_VECTORS, PCI_IRQ_MSI);
67 
68 	if (ipc_pcie->nvec < 0) {
69 		rc = ipc_pcie->nvec;
70 		goto error;
71 	}
72 
73 	if (!pdev->msi_enabled)
74 		goto error;
75 
76 	for (i = 0; i < ipc_pcie->nvec; ++i) {
77 		rc = request_threaded_irq(pdev->irq + i, NULL,
78 					  ipc_msi_interrupt, IRQF_ONESHOT,
79 					  KBUILD_MODNAME, ipc_pcie);
80 		if (rc) {
81 			dev_err(ipc_pcie->dev, "unable to grab IRQ, rc=%d", rc);
82 			ipc_pcie->nvec = i;
83 			ipc_release_irq(ipc_pcie);
84 			goto error;
85 		}
86 	}
87 
88 error:
89 	return rc;
90 }
91