[PATCH v1 4/8] x86/psp: Add IRQ support

Jeremi Piotrowski
2023-01-23T15:25:15Z

The ACPI PSP device provides a mailbox irq that needs to be configured
through the ACPI mailbox register first. This requires passing a CPU
vector and physical CPU id and then enabling interrupt delivery.
Allocate the irq directly from the default irq domain
(x86_vector_domain) to get access to the required information. By
passing a cpumask through irq_alloc_info the vector is immediately
allocated (and not later during activation) and can be retrieved.

Signed-off-by: Jeremi Piotrowski <jpiotrowski@linux.microsoft.com>
---
arch/x86/kernel/psp.c | 179 +++++++++++++++++++++++++++++++++++++++++-
1 file changed, 175 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/psp.c b/arch/x86/kernel/psp.c
index d404df47cc04..24181d132bae 100644
--- a/arch/x86/kernel/psp.c
+++ b/arch/x86/kernel/psp.c
@@ -1,8 +1,176 @@
// SPDX-License-Identifier: GPL-2.0-only
-
+#define pr_fmt(fmt) "psp: " fmt
#include <linux/platform_data/psp.h>
#include <linux/platform_device.h>
+#include <linux/iopoll.h>
+#include <linux/irq.h>
#include <asm/hypervisor.h>
+#include <asm/irqdomain.h>
+
+#define PSP_ACPI_DATA_SHIFT 0
+#define PSP_ACPI_DATA_MASK GENMASK(15, 0)
+#define PSP_ACPI_CMDID_SHIFT 16
+#define PSP_ACPI_CMDID_MASK GENMASK(25, 16)
+#define PSP_ACPI_STATUS_SHIFT 26
+#define PSP_ACPI_STATUS_MASK GENMASK(30, 26)
+#define PSP_ACPI_RESPONSE_BIT BIT(31)
+
+#define PSP_ACPI_VECTOR_SHIFT 0
+#define PSP_ACPI_VECTOR_MASK GENMASK(7, 0)
+#define PSP_ACPI_MBOX_IRQID_SHIFT 10
+#define PSP_ACPI_MBOX_IRQID_MASK GENMASK(15, 10)
+
+#define PSP_ACPI_IRQ_EN_BIT BIT(0)
+#define PSP_ACPI_IRQ_EN_MBOX_IRQID_SHIFT 10
+#define PSP_ACPI_IRQ_EN_MBOX_IRQID_MASK GENMASK(15, 10)
+
+// AMD Secure Processor
+enum ASP_CMDID {
+ ASP_CMDID_PART1 = 0x82,
+ ASP_CMDID_PART2 = 0x83,
+ ASP_CMDID_PART3 = 0x84,
+ ASP_CMDID_IRQ_EN = 0x85,
+};
+
+enum ASP_CMD_STATUS {
+ ASP_CMD_STATUS_SUCCESS = 0x0,
+ ASP_CMD_STATUS_INVALID_CMD = 0x1,
+ ASP_CMD_STATUS_INVALID_PARAM = 0x2,
+ ASP_CMD_STATUS_INVALID_FW_STATE = 0x3,
+ ASP_CMD_STATUS_FAILURE = 0x1F,
+};
+
+struct psp_irq_data {
+ void __iomem *base;
+ int mbox_irq_id;
+ int acpi_cmd_resp_reg;
+};
+
+static int psp_sync_cmd(void __iomem *reg, u8 cmd, u16 data)
+{
+ u32 val = 0;
+ int err;
+
+ val |= data & PSP_ACPI_DATA_MASK;
+ val |= (cmd << PSP_ACPI_CMDID_SHIFT) & PSP_ACPI_CMDID_MASK;
+ writel(val, reg);
+ err = readl_poll_timeout_atomic(reg, val, val & PSP_ACPI_RESPONSE_BIT, 2, 10000);
+ if (err < 0)
+ return err;
+ return (val & PSP_ACPI_STATUS_MASK) >> PSP_ACPI_STATUS_SHIFT;
+}
+
+static int psp_set_irq_enable(struct psp_irq_data *data, bool irq_en)
+{
+ void __iomem *reg = data->base + data->acpi_cmd_resp_reg;
+ u8 mbox_irq_id = data->mbox_irq_id;
+ u16 val = 0;
+ int err;
+
+ val |= irq_en ? PSP_ACPI_IRQ_EN_BIT : 0;
+ val |= (mbox_irq_id << PSP_ACPI_IRQ_EN_MBOX_IRQID_SHIFT) & PSP_ACPI_IRQ_EN_MBOX_IRQID_MASK;
+ err = psp_sync_cmd(reg, ASP_CMDID_IRQ_EN, val);
+ if (err != ASP_CMD_STATUS_SUCCESS) {
+ pr_err("ASP_CMDID_IRQ_EN failed: %d\n", err);
+ return -EIO;
+ }
+ return 0;
+}
+
+static int psp_configure_irq(struct psp_irq_data *data, int vector, unsigned int cpu)
+{
+ void __iomem *reg = data->base + data->acpi_cmd_resp_reg;
+ unsigned int dest_cpu = cpu_physical_id(cpu);
+ u8 mbox_irq_id = data->mbox_irq_id;
+ u16 part1, part2, part3;
+ int err;
+
+ part1 = dest_cpu;
+ part2 = dest_cpu >> 16;
+ part3 = vector & PSP_ACPI_VECTOR_MASK;
+ part3 |= (mbox_irq_id << PSP_ACPI_MBOX_IRQID_SHIFT) & PSP_ACPI_MBOX_IRQID_MASK;
+
+ err = psp_sync_cmd(reg, ASP_CMDID_PART1, part1);
+ if (err != ASP_CMD_STATUS_SUCCESS) {
+ pr_err("ASP_CMDID_PART1 failed: %d\n", err);
+ return -EIO;
+ }
+ err = psp_sync_cmd(reg, ASP_CMDID_PART2, part2);
+ if (err != ASP_CMD_STATUS_SUCCESS) {
+ pr_err("ASP_CMDID_PART2 failed: %d\n", err);
+ return -EIO;
+ }
+ err = psp_sync_cmd(reg, ASP_CMDID_PART3, part3);
+ if (err != ASP_CMD_STATUS_SUCCESS) {
+ pr_err("ASP_CMDID_PART3 failed: %d\n", err);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+
+static int psp_init_irq(const struct psp_platform_data *pdata,
+ const struct resource *reg, struct resource *irq)
+{
+ struct psp_irq_data pspirqd;
+ struct irq_alloc_info info;
+ struct irq_data *data = NULL;
+ struct irq_cfg *cfg = NULL;
+ void __iomem *base = NULL;
+ int virq;
+ int err;
+
+ base = ioremap(reg->start, resource_size(reg));
+ if (IS_ERR(base))
+ return PTR_ERR(base);
+ if (!base)
+ return -ENOMEM;
+ pspirqd.mbox_irq_id = pdata->mbox_irq_id;
+ pspirqd.acpi_cmd_resp_reg = pdata->acpi_cmd_resp_reg;
+ pspirqd.base = base;
+ init_irq_alloc_info(&info, cpumask_of(0));
+ virq = irq_domain_alloc_irqs(NULL, 1, NUMA_NO_NODE, &info);
+ if (virq <= 0) {
+ pr_err("failed to allocate vector: %d\n", virq);
+ err = -ENOMEM;
+ goto unmap;
+ }
+ irq_set_handler(virq, handle_edge_irq);
+ data = irq_get_irq_data(virq);
+ if (!data) {
+ pr_err("no irq data\n");
+ err = -ENODEV;
+ goto freeirq;
+
+ }
+ cfg = irqd_cfg(data);
+ if (!data) {
+ pr_err("no irq cfg\n");
+ err = -ENODEV;
+ goto freeirq;
+ }
+ err = psp_configure_irq(&pspirqd, cfg->vector, 0);
+ if (err) {
+ pr_err("failed to configure irq: %d\n", err);
+ goto freeirq;
+ }
+ err = psp_set_irq_enable(&pspirqd, true);
+ if (err) {
+ pr_err("failed to enable irq: %d\n", err);
+ goto freeirq;
+ }
+
+ *irq = (struct resource)DEFINE_RES_IRQ(virq);
+ iounmap(base);
+ return 0;
+
+freeirq:
+ irq_domain_free_irqs(virq, 1);
+unmap:
+ iounmap(base);
+ return err;
+}

static struct platform_device psp_device = {
.name = "psp",
@@ -12,7 +180,7 @@ static struct platform_device psp_device = {
static int __init psp_init_platform_device(void)
{
struct psp_platform_data pdata = {};
- struct resource res[1];
+ struct resource res[2];
int err;

/*
@@ -24,10 +192,13 @@ static int __init psp_init_platform_device(void)
if (!hypervisor_is_type(X86_HYPER_MS_HYPERV))
return -ENODEV;

- err = acpi_parse_aspt(res, &pdata);
+ err = acpi_parse_aspt(&res[0], &pdata);
+ if (err)
+ return err;
+ err = psp_init_irq(&pdata, &res[0], &res[1]);
if (err)
return err;
- err = platform_device_add_resources(&psp_device, res, 1);
+ err = platform_device_add_resources(&psp_device, res, 2);
if (err)
return err;

--
2.25.1