tpm_tis: Revert "tpm_tis: Disable interrupts on ThinkPad T490s"

Since for MMIO driver using FIFO registers, also known as tpm_tis, the
default (and tbh recommended) behaviour is now the polling mode, the
"tristate" workaround is no longer for benefit.

If someone wants to explicitly enable IRQs for a TPM chip that should be
without question allowed. It could very well be a piece hardware in the
existing deny list because of e.g. firmware update or something similar.

While at it, document the module parameter, as this was not done in 2006
when it first appeared in the mainline.

Link: https://lore.kernel.org/linux-integrity/20201015214430.17937-1-jsnitsel@redhat.com/
Link: https://lore.kernel.org/all/1145393776.4829.19.camel@localhost.localdomain/Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>

Documentation/admin-guide/kernel-parameters.txt

@@ -6340,6 +6340,13 @@
 			This will guarantee that all the other pcrs
 			are saved.
 
+	tpm_tis.interrupts= [HW,TPM]
+			Enable interrupts for the MMIO based physical layer
+			for the FIFO interface. By default it is set to false
+			(0). For more information about TPM hardware interfaces
+			defined by Trusted Computing Group (TCG) see
+			https://trustedcomputinggroup.org/resource/pc-client-platform-tpm-profile-ptp-specification/
+
 	tp_printk	[FTRACE]
 			Have the tracepoints sent to printk as well as the
 			tracing ring buffer. This is useful for early boot up

drivers/char/tpm/tpm_tis.c

@@ -27,7 +27,6 @@
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/kernel.h>
-#include <linux/dmi.h>
 #include "tpm.h"
 #include "tpm_tis_core.h"
 
@@ -89,8 +88,8 @@ static inline void tpm_tis_iowrite32(u32 b, void __iomem *iobase, u32 addr)
 	tpm_tis_flush(iobase);
 }
 
-static int interrupts;
-module_param(interrupts, int, 0444);
+static bool interrupts;
+module_param(interrupts, bool, 0444);
 MODULE_PARM_DESC(interrupts, "Enable interrupts");
 
 static bool itpm;
@@ -103,92 +102,6 @@ module_param(force, bool, 0444);
 MODULE_PARM_DESC(force, "Force device probe rather than using ACPI entry");
 #endif
 
-static int tpm_tis_disable_irq(const struct dmi_system_id *d)
-{
-	if (interrupts == -1) {
-		pr_notice("tpm_tis: %s detected: disabling interrupts.\n", d->ident);
-		interrupts = 0;
-	}
-
-	return 0;
-}
-
-static const struct dmi_system_id tpm_tis_dmi_table[] = {
-	{
-		.callback = tpm_tis_disable_irq,
-		.ident = "Framework Laptop (12th Gen Intel Core)",
-		.matches = {
-			DMI_MATCH(DMI_SYS_VENDOR, "Framework"),
-			DMI_MATCH(DMI_PRODUCT_NAME, "Laptop (12th Gen Intel Core)"),
-		},
-	},
-	{
-		.callback = tpm_tis_disable_irq,
-		.ident = "Framework Laptop (13th Gen Intel Core)",
-		.matches = {
-			DMI_MATCH(DMI_SYS_VENDOR, "Framework"),
-			DMI_MATCH(DMI_PRODUCT_NAME, "Laptop (13th Gen Intel Core)"),
-		},
-	},
-	{
-		.callback = tpm_tis_disable_irq,
-		.ident = "ThinkPad T490s",
-		.matches = {
-			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
-			DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T490s"),
-		},
-	},
-	{
-		.callback = tpm_tis_disable_irq,
-		.ident = "ThinkStation P360 Tiny",
-		.matches = {
-			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
-			DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkStation P360 Tiny"),
-		},
-	},
-	{
-		.callback = tpm_tis_disable_irq,
-		.ident = "ThinkPad L490",
-		.matches = {
-			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
-			DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad L490"),
-		},
-	},
-	{
-		.callback = tpm_tis_disable_irq,
-		.ident = "ThinkPad L590",
-		.matches = {
-			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
-			DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad L590"),
-		},
-	},
-	{
-		.callback = tpm_tis_disable_irq,
-		.ident = "ThinkStation P620",
-		.matches = {
-			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
-			DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkStation P620"),
-		},
-	},
-	{
-		.callback = tpm_tis_disable_irq,
-		.ident = "TUXEDO InfinityBook S 15/17 Gen7",
-		.matches = {
-			DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
-			DMI_MATCH(DMI_PRODUCT_NAME, "TUXEDO InfinityBook S 15/17 Gen7"),
-		},
-	},
-	{
-		.callback = tpm_tis_disable_irq,
-		.ident = "UPX-TGL",
-		.matches = {
-			DMI_MATCH(DMI_SYS_VENDOR, "AAEON"),
-			DMI_MATCH(DMI_PRODUCT_NAME, "UPX-TGL01"),
-		},
-	},
-	{}
-};
-
 #if defined(CONFIG_PNP) && defined(CONFIG_ACPI)
 static int has_hid(struct acpi_device *dev, const char *hid)
 {
@@ -312,8 +225,6 @@ static int tpm_tis_init(struct device *dev, struct tpm_info *tpm_info)
 	int irq = -1;
 	int rc;
 
-	dmi_check_system(tpm_tis_dmi_table);
-
 	rc = check_acpi_tpm2(dev);
 	if (rc)
 		return rc;