[tpmdd-devel,v2,3/3] tpm_tis: Clean up the force=1 module parameter
diff mbox

Message ID 1448996309-15220-4-git-send-email-jgunthorpe@obsidianresearch.com
State New
Headers show

Commit Message

Jason Gunthorpe Dec. 1, 2015, 6:58 p.m. UTC
The TPM core has long assumed that every device has a driver attached,
however commit b8b2c7d845d5 ("base/platform: assert that dev_pm_domain
callbacks are called unconditionally") breaks that assumption.

Rework the TPM setup to create a platform device with resources and
then allow the driver core to naturally bind and probe it through the
normal mechanisms. All this structure is needed anyhow to enable TPM
for OF environments.

Finally, since the entire flow is changing convert the init/exit to use
the modern ifdef-less coding style when possible

Reported-by: "Wilck, Martin" <martin.wilck@ts.fujitsu.com>
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
---
 drivers/char/tpm/tpm_tis.c | 170 +++++++++++++++++++++++++++------------------
 1 file changed, 104 insertions(+), 66 deletions(-)

Comments

Uwe Kleine-König Dec. 1, 2015, 7:33 p.m. UTC | #1
Hello,

On Tue, Dec 01, 2015 at 11:58:29AM -0700, Jason Gunthorpe wrote:
> The TPM core has long assumed that every device has a driver attached,
> however commit b8b2c7d845d5 ("base/platform: assert that dev_pm_domain
> callbacks are called unconditionally") breaks that assumption.

you asked for an alternative wording here. What about:

	The TPM core has long assumed that every device has a driver
	attached, which is not valid. This was noticed with commit
	b8b2c7d845d5 ("base/platform: assert that dev_pm_domain
	callbacks are called unconditionally") which made probing of the
	tpm_tis device fail by mistake and resulted in an oops later on.
	
?

> Rework the TPM setup to create a platform device with resources and
> then allow the driver core to naturally bind and probe it through the
> normal mechanisms. All this structure is needed anyhow to enable TPM
> for OF environments.
> 
> Finally, since the entire flow is changing convert the init/exit to use
> the modern ifdef-less coding style when possible
> 
> Reported-by: "Wilck, Martin" <martin.wilck@ts.fujitsu.com>
> Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>

Best regards,
Uwe
Jason Gunthorpe Dec. 1, 2015, 7:51 p.m. UTC | #2
On Tue, Dec 01, 2015 at 08:33:58PM +0100, Uwe Kleine-König wrote:
> Hello,
> 
> On Tue, Dec 01, 2015 at 11:58:29AM -0700, Jason Gunthorpe wrote:
> > The TPM core has long assumed that every device has a driver attached,
> > however commit b8b2c7d845d5 ("base/platform: assert that dev_pm_domain
> > callbacks are called unconditionally") breaks that assumption.
> 
> you asked for an alternative wording here. What about:
> 
> 	The TPM core has long assumed that every device has a driver
> 	attached, which is not valid.

But it is valid, it is an invariant of the tpm core that a driver be
attached, and prior to 'b8b that has been satisfied.

>       This was noticed with commit
> 	b8b2c7d845d5 ("base/platform: assert that dev_pm_domain
> 	callbacks are called unconditionally") which made probing of the
> 	tpm_tis device fail by mistake and resulted in an oops later on.

The probe didn't fail, the 'b8b causes a NULL probe function to result
in no driver being attached.

How about:

 The TPM has for a long time required that every device it uses has an
 attached driver. In the force case the tpm_tis driver met this via
 platform_register_simple and a NULL probe function for the driver.
 However, commit b8b2c7d845d5 ("base/platform: assert that dev_pm_domain
 callbacks are called unconditionally") causes NULL probe functions
 to no longer bind a driver.

Did we ever reach a conclusion if Martin's patch should go ahead?

Jason

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Patch
diff mbox

diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c
index 1032855c46b2..19beaf57f2a9 100644
--- a/drivers/char/tpm/tpm_tis.c
+++ b/drivers/char/tpm/tpm_tis.c
@@ -60,8 +60,6 @@  enum tis_int_flags {
 };
 
 enum tis_defaults {
-	TIS_MEM_BASE = 0xFED40000,
-	TIS_MEM_LEN = 0x5000,
 	TIS_SHORT_TIMEOUT = 750,	/* ms */
 	TIS_LONG_TIMEOUT = 2000,	/* 2 sec */
 };
@@ -71,15 +69,6 @@  struct tpm_info {
 	int irq;
 };
 
-static struct tpm_info tis_default_info = {
-	.res = {
-		.start = TIS_MEM_BASE,
-		.end = TIS_MEM_BASE + TIS_MEM_LEN - 1,
-		.flags = IORESOURCE_MEM,
-	},
-	.irq = 0,
-};
-
 /* Some timeout values are needed before it is known whether the chip is
  * TPM 1.0 or TPM 2.0.
  */
@@ -849,7 +838,6 @@  out_err:
 	return rc;
 }
 
-#ifdef CONFIG_PM_SLEEP
 static void tpm_tis_reenable_interrupts(struct tpm_chip *chip)
 {
 	u32 intmask;
@@ -891,11 +879,9 @@  static int tpm_tis_resume(struct device *dev)
 
 	return 0;
 }
-#endif
 
 static SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend, tpm_tis_resume);
 
-#ifdef CONFIG_PNP
 static int tpm_tis_pnp_init(struct pnp_dev *pnp_dev,
 			    const struct pnp_device_id *pnp_id)
 {
@@ -913,14 +899,12 @@  static int tpm_tis_pnp_init(struct pnp_dev *pnp_dev,
 	else
 		tpm_info.irq = -1;
 
-#ifdef CONFIG_ACPI
 	if (pnp_acpi_device(pnp_dev)) {
 		if (is_itpm(pnp_acpi_device(pnp_dev)))
 			itpm = true;
 
-		acpi_dev_handle = pnp_acpi_device(pnp_dev)->handle;
+		acpi_dev_handle = ACPI_HANDLE(&pnp_dev->dev);
 	}
-#endif
 
 	return tpm_tis_init(&pnp_dev->dev, &tpm_info, acpi_dev_handle);
 }
@@ -961,7 +945,6 @@  static struct pnp_driver tis_pnp_driver = {
 module_param_string(hid, tpm_pnp_tbl[TIS_HID_USR_IDX].id,
 		    sizeof(tpm_pnp_tbl[TIS_HID_USR_IDX].id), 0444);
 MODULE_PARM_DESC(hid, "Set additional specific HID for this driver to probe");
-#endif
 
 #ifdef CONFIG_ACPI
 static int tpm_check_resource(struct acpi_resource *ares, void *data)
@@ -1034,80 +1017,135 @@  static struct acpi_driver tis_acpi_driver = {
 };
 #endif
 
+static struct platform_device *force_pdev;
+
+static int tpm_tis_plat_probe(struct platform_device *pdev)
+{
+	struct tpm_info tpm_info = {};
+	struct resource *res;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (res == NULL) {
+		dev_err(&pdev->dev, "no memory resource defined\n");
+		return -ENODEV;
+	}
+	memcpy(&tpm_info.res, res, sizeof(*res));
+
+	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	if (res) {
+		tpm_info.irq = res->start;
+	} else {
+		if (pdev == force_pdev)
+			tpm_info.irq = -1;
+		else
+			/* When forcing auto probe the IRQ */
+			tpm_info.irq = 0;
+	}
+
+	return tpm_tis_init(&pdev->dev, &tpm_info, NULL);
+}
+
+static int tpm_tis_plat_remove(struct platform_device *pdev)
+{
+	struct tpm_chip *chip = dev_get_drvdata(&pdev->dev);
+
+	tpm_chip_unregister(chip);
+	tpm_tis_remove(chip);
+
+	return 0;
+}
+
 static struct platform_driver tis_drv = {
+	.probe = tpm_tis_plat_probe,
+	.remove = tpm_tis_plat_remove,
 	.driver = {
 		.name		= "tpm_tis",
 		.pm		= &tpm_tis_pm,
 	},
 };
 
-static struct platform_device *pdev;
-
 static bool force;
+#ifdef CONFIG_X86
 module_param(force, bool, 0444);
 MODULE_PARM_DESC(force, "Force device probe rather than using ACPI entry");
+#endif
+
+static int force_device(void)
+{
+	struct platform_device *pdev;
+	static const struct resource x86_resources[] = {
+		{
+			.start = 0xFED40000,
+			.end = 0xFED44FFF,
+			.flags = IORESOURCE_MEM,
+		},
+	};
+
+	if (!force)
+		return 0;
+
+	/* The driver core will match the name tpm_tis of the device to
+	 * the tpm_tis platform driver and complete the setup via
+	 * tpm_tis_plat_probe
+	 */
+	pdev = platform_device_register_simple("tpm_tis", -1, x86_resources,
+					       ARRAY_SIZE(x86_resources));
+	if (IS_ERR(pdev))
+		return PTR_ERR(pdev);
+	force_pdev = pdev;
+
+	return 0;
+}
+
 static int __init init_tis(void)
 {
 	int rc;
-#ifdef CONFIG_PNP
-	if (!force) {
-		rc = pnp_register_driver(&tis_pnp_driver);
-		if (rc)
-			return rc;
-	}
-#endif
+
+	rc = force_device();
+	if (rc)
+		goto err_force;
+
+	rc = platform_driver_register(&tis_drv);
+	if (rc)
+		goto err_platform;
+
 #ifdef CONFIG_ACPI
-	if (!force) {
-		rc = acpi_bus_register_driver(&tis_acpi_driver);
-		if (rc) {
-#ifdef CONFIG_PNP
-			pnp_unregister_driver(&tis_pnp_driver);
-#endif
-			return rc;
-		}
-	}
+	rc = acpi_bus_register_driver(&tis_acpi_driver);
+	if (rc)
+		goto err_acpi;
 #endif
-	if (!force)
-		return 0;
 
-	rc = platform_driver_register(&tis_drv);
-	if (rc < 0)
-		return rc;
-	pdev = platform_device_register_simple("tpm_tis", -1, NULL, 0);
-	if (IS_ERR(pdev)) {
-		rc = PTR_ERR(pdev);
-		goto err_dev;
+	if (IS_ENABLED(CONFIG_PNP)) {
+		rc = pnp_register_driver(&tis_pnp_driver);
+		if (rc)
+			goto err_pnp;
 	}
-	rc = tpm_tis_init(&pdev->dev, &tis_default_info, NULL);
-	if (rc)
-		goto err_init;
+
 	return 0;
-err_init:
-	platform_device_unregister(pdev);
-err_dev:
-	platform_driver_unregister(&tis_drv);
+
+err_pnp:
+#ifdef CONFIG_ACPI
+	acpi_bus_unregister_driver(&tis_acpi_driver);
+err_acpi:
+#endif
+	platform_device_unregister(force_pdev);
+err_platform:
+	if (force_pdev)
+		platform_device_unregister(force_pdev);
+err_force:
 	return rc;
 }
 
 static void __exit cleanup_tis(void)
 {
-	struct tpm_chip *chip;
-#if defined(CONFIG_PNP) || defined(CONFIG_ACPI)
-	if (!force) {
+	pnp_unregister_driver(&tis_pnp_driver);
 #ifdef CONFIG_ACPI
-		acpi_bus_unregister_driver(&tis_acpi_driver);
-#endif
-#ifdef CONFIG_PNP
-		pnp_unregister_driver(&tis_pnp_driver);
-#endif
-		return;
-	}
+	acpi_bus_unregister_driver(&tis_acpi_driver);
 #endif
-	chip = dev_get_drvdata(&pdev->dev);
-	tpm_chip_unregister(chip);
-	tpm_tis_remove(chip);
-	platform_device_unregister(pdev);
 	platform_driver_unregister(&tis_drv);
+
+	if (force_pdev)
+		platform_device_unregister(force_pdev);
 }
 
 module_init(init_tis);