Date:	Thu, 17 Dec 2015 11:23:18 -0700
From:	Jason Gunthorpe <jgunthorpe@...idianresearch.com>
To:	Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
	tpmdd-devel@...ts.sourceforge.net, linux-kernel@...r.kernel.org
Cc:	Martin Wilck <Martin.Wilck@...fujitsu.com>,
	Peter Huewe <peterhuewe@....de>,
	Uwe Kleine-König 
	<u.kleine-koenig@...gutronix.de>
Subject: [PATCH v3 5/7] tpm_tis: Clean up the force=1 module parameter

The TPM core has long assumed that every device has a driver attached,
however the force path was attaching the TPM core outside of a driver
context. This isn't generally reliable as the user could detatch the
driver using sysfs or something, but commit b8b2c7d845d5 ("base/platform:
assert that dev_pm_domain callbacks are called unconditionally")
forced the issue by leaving the driver pointer NULL if there is
no probe.

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@...fujitsu.com>
Signed-off-by: Jason Gunthorpe <jgunthorpe@...idianresearch.com>
Tested-by: Wilck, Martin <martin.wilck@...fujitsu.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
---
 drivers/char/tpm/tpm_tis.c | 173 +++++++++++++++++++++++++++------------------
 1 file changed, 106 insertions(+), 67 deletions(-)

diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c
index 856fb35e574c..12aa96a69b6c 100644
--- a/drivers/char/tpm/tpm_tis.c
+++ b/drivers/char/tpm/tpm_tis.c
@@ -60,7 +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 */
@@ -75,15 +74,6 @@ 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.
  */
@@ -695,8 +685,8 @@ static int tpm_tis_init(struct device *dev, struct tpm_info *tpm_info,
 #endif
 
 	chip->vendor.iobase = devm_ioremap_resource(dev, &tpm_info->res);
-	if (!chip->vendor.iobase)
-		return -EIO;
+	if (IS_ERR(chip->vendor.iobase))
+		return PTR_ERR(chip->vendor.iobase);
 
 	/* Maximum timeouts */
 	chip->vendor.timeout_a = TIS_TIMEOUT_A_MAX;
@@ -825,7 +815,6 @@ out_err:
 	return rc;
 }
 
-#ifdef CONFIG_PM_SLEEP
 static void tpm_tis_reenable_interrupts(struct tpm_chip *chip)
 {
 	u32 intmask;
@@ -867,11 +856,9 @@ 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)
 {
@@ -889,14 +876,12 @@ 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);
 }
@@ -937,7 +922,6 @@ 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)
@@ -1024,80 +1008,135 @@ 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;
+	}
+	tpm_info.res = *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 tpm_tis_force_device(void)
+{
+	struct platform_device *pdev;
+	static const struct resource x86_resources[] = {
+		{
+			.start = 0xFED40000,
+			.end = 0xFED40000 + TIS_MEM_LEN - 1,
+			.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 = tpm_tis_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);
-- 
2.1.4

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