soc/intel/common/block/gpio: add code for NMI enabling

Especially server boards, like the Supermicro X11SSM-F, often have a NMI
button and NMI functionality that can be triggered via IPMI. The purpose
of this is to cause the OS to create a system crashdump from a hang
system or for debugging.

Add code for enabling NMI interrupts on GPIOs configured with
PAD_CFG_GPI_NMI. The enabling mechanism is the same as SMI, so the SMI
function was copied and adapted. The `pad_community` struct gained two
variables for the registers.

Also register the NMI for LINT1 in the MADT in accordance to ACPI spec.

Test: Linux detects the NMI correctly in dmesg:
[    0.053734] ACPI: LAPIC_NMI (acpi_id[0xff] high edge lint[0x1])

Signed-off-by: Michael Niewöhner <foss@mniewoehner.de>
Change-Id: I4fc1a35c99c6a28b20e08a80b97bb4b8624935c9
Reviewed-on: https://review.coreboot.org/c/coreboot/+/48090
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/intel/common/block/acpi/acpi.c

@@ -79,6 +79,9 @@ static unsigned long acpi_madt_irq_overrides(unsigned long current)
 	current +=
 	    acpi_create_madt_irqoverride((void *)current, 0, sci, sci, flags);
 
+	/* NMI */
+	current += acpi_create_madt_lapic_nmi((acpi_madt_lapic_nmi_t *)current, 0xff, 5, 1);
+
 	return current;
 }
 

src/soc/intel/common/block/gpio/gpio.c

@@ -48,6 +48,10 @@
 				((group) * sizeof(uint32_t)))
 #define GPI_SMI_EN_OFFSET(comm, group) ((comm)->gpi_smi_en_reg_0 +	\
 				((group) * sizeof(uint32_t)))
+#define GPI_NMI_STS_OFFSET(comm, group) ((comm)->gpi_nmi_sts_reg_0 +	\
+				((group) * sizeof(uint32_t)))
+#define GPI_NMI_EN_OFFSET(comm, group) ((comm)->gpi_nmi_en_reg_0 +	\
+				((group) * sizeof(uint32_t)))
 #define GPI_IS_OFFSET(comm, group) ((comm)->gpi_int_sts_reg_0 +	\
 				((group) * sizeof(uint32_t)))
 #define GPI_IE_OFFSET(comm, group) ((comm)->gpi_int_en_reg_0 +	\
@@ -176,6 +180,35 @@ static void gpi_enable_smi(const struct pad_config *cfg,
 	pcr_or32(comm->port, en_reg, en_value);
 }
 
+static void gpi_enable_nmi(const struct pad_config *cfg,
+				const struct pad_community *comm)
+{
+	uint16_t sts_reg;
+	uint16_t en_reg;
+	uint32_t en_value;
+	int group;
+	int pin;
+
+	if (((cfg->pad_config[0]) & PAD_CFG0_ROUTE_NMI) != PAD_CFG0_ROUTE_NMI)
+		return;
+
+	/* Do not configure NMI if the platform doesn't support it */
+	if (!comm->gpi_nmi_sts_reg_0 || !comm->gpi_nmi_en_reg_0)
+		return;
+
+	pin = relative_pad_in_comm(comm, cfg->pad);
+	group = gpio_group_index(comm, pin);
+	sts_reg = GPI_NMI_STS_OFFSET(comm, group);
+	en_reg = GPI_NMI_EN_OFFSET(comm, group);
+	en_value = gpio_bitmask_within_group(comm, pin);
+
+	/* Write back 1 to reset the sts bit */
+	pcr_rmw32(comm->port, sts_reg, en_value, 0);
+
+	/* Set enable bits */
+	pcr_or32(comm->port, en_reg, en_value);
+}
+
 static void gpio_configure_itss(const struct pad_config *cfg, uint16_t port,
 	uint16_t  pad_cfg_offset)
 {
@@ -283,6 +316,7 @@ static void gpio_configure_pad(const struct pad_config *cfg)
 	gpio_configure_itss(cfg, comm->port, config_offset);
 	gpio_configure_owner(cfg, comm);
 	gpi_enable_smi(cfg, comm);
+	gpi_enable_nmi(cfg, comm);
 }
 
 void gpio_configure_pads(const struct pad_config *cfg, size_t num_pads)

src/soc/intel/common/block/include/intelblocks/gpio.h

@@ -111,6 +111,8 @@ struct pad_community {
 	uint16_t	gpi_int_en_reg_0; /* offset to GPI Int Enable Reg 0 */
 	uint16_t	gpi_smi_sts_reg_0; /* offset to GPI SMI STS Reg 0 */
 	uint16_t	gpi_smi_en_reg_0; /* offset to GPI SMI EN Reg 0 */
+	uint16_t	gpi_nmi_sts_reg_0; /* offset to GPI NMI STS Reg 0 */
+	uint16_t	gpi_nmi_en_reg_0; /* offset to GPI NMI EN Reg 0 */
 	uint16_t	pad_cfg_base; /* offset to first PAD_GFG_DW0 Reg */
 	uint8_t		gpi_status_offset;  /* specifies offset in struct
 						gpi_status */

src/soc/intel/skylake/acpi.c

@@ -522,6 +522,9 @@ unsigned long acpi_madt_irq_overrides(unsigned long current)
 	irqovr = (void *)current;
 	current += acpi_create_madt_irqoverride(irqovr, 0, sci, sci, flags);
 
+	/* NMI */
+	current += acpi_create_madt_lapic_nmi((acpi_madt_lapic_nmi_t *)current, 0xff, 5, 1);
+
 	return current;
 }