linux-kernel - Re: [PATCH 5/6] tpm_tis: convert from pnp_driver to acpi

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Message-Id: <1246455920.9140.28.camel@blackbox>
Date:	Wed, 01 Jul 2009 10:45:19 -0300
From:	Rajiv Andrade <srajiv@...ux.vnet.ibm.com>
To:	Alan Cox <alan@...rguk.ukuu.org.uk>
Cc:	Andy Isaacson <adi@...are.com>, linux-kernel@...r.kernel.org,
	tpmdd-devel@...ts.sourceforge.net, adi@...apodia.org,
	dds@...gle.com, Mimi Zohar <zohar@...ux.vnet.ibm.com>,
	Shahbaz Khan <shaz.linux@...il.com>, seiji.munetoh@...il.com
Subject: Re: [PATCH 5/6] tpm_tis: convert from pnp_driver to acpi_driver


On Wed, 2009-07-01 at 11:01 +0100, Alan Cox wrote:
> On Tue, 30 Jun 2009 18:04:14 -0700
> Andy Isaacson <adi@...are.com> wrote:
> 
> > Not all TIS-compatible TPM chips have a _HID method in their ACPI entry,
> > and the TPM spec says that the _CID method should be used to enumerate
> > the TPM chip.
> 
> There are a number of systems with TPMs (older laptops) that don't work
> very well if you enable ACPI.
> 
> This is therefore a regression - NAK
> 
> Probably the best thing to do is to provide both ACPI and PnP
> registration according to what is configured into the kernel. (And I
> guess spot duplicates although the resource should be busy anyway)
> --
David sent this earlier when I said that PNP didn't work with this chip:
        
<quote>
The problem here is acpi pnp but the fix is really simple. The current
pnpacpi/core.c routine that looks for isapnp devices enumerated in acpi
enforces that the acpi hid be a valid isapnp id (the formats are
slightly different). But that's broken: it shoudl be enforcing that
either the acpi hid or any acpi cids be valid isapnp ids. It's a
one-line change to do this, see patch 2. 

commit 7a553b4e7439ad0733da7da8663d32aa4865aa9e
Author: David Smith <dds@...gle.com>
Date:   Tue Apr 28 18:52:02 2009 +0900

    Update ACPI PNP to support devices with EISA PNP CIDs but non-PNP HIDs
    
    Signed-off-by: David Smith <dds@...gle.com>

diff --git a/drivers/pnp/pnpacpi/core.c b/drivers/pnp/pnpacpi/core.c
index 9496494..8bfddfb 100644
--- a/drivers/pnp/pnpacpi/core.c
+++ b/drivers/pnp/pnpacpi/core.c
@@ -159,8 +159,8 @@ static int __init pnpacpi_add_device(struct acpi_device *device)
 	 * driver should not be loaded.
 	 */
 	status = acpi_get_handle(device->handle, "_CRS", &temp);
-	if (ACPI_FAILURE(status) || !ispnpidacpi(acpi_device_hid(device)) ||
-	    is_exclusive_device(device) || (!device->status.present))
+	if (ACPI_FAILURE(status) || is_exclusive_device(device) ||
+            (!device->status.present))
 		return 0;
 
 	dev = pnp_alloc_dev(&pnpacpi_protocol, num, acpi_device_hid(device));

</quote>

If so, we can just base our DATA_EXPECT bypass on the EISA PNP CID:

>>From 47516ff6b63b81d1e806148dc5e3052a001e45d0 Mon Sep 17 00:00:00 2001
From: Rajiv Andrade <srajiv@...ux.vnet.ibm.com>
Date: Wed, 1 Jul 2009 09:59:55 -0300
Subject: [PATCH] TPM: DATA_EXPECT bit check bypass

Since the iTPM doesn't set the DATA_EXPECT bit when it should, we bypass
this bit check in case we're running the code over this specific TPM.

Signed-off-by: Rajiv Andrade <srajiv@...ux.vnet.ibm.com>
---
 drivers/char/tpm/tpm.h     |    1 +
 drivers/char/tpm/tpm_tis.c |   11 ++++++++++-
 2 files changed, 11 insertions(+), 1 deletions(-)

diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 8e00b4d..ed4ecf0 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -109,6 +109,7 @@ struct tpm_chip {
 
 	struct list_head list;
 	void (*release) (struct device *);
+	bool is_itpm;
 };
 
 #define to_tpm_chip(n) container_of(n, struct tpm_chip, vendor)
diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c
index aec1931..74a60d7 100644
--- a/drivers/char/tpm/tpm_tis.c
+++ b/drivers/char/tpm/tpm_tis.c
@@ -27,6 +27,7 @@
 #include "tpm.h"
 
 #define TPM_HEADER_SIZE 10
+#define ITPM_ID "INTC0102"
 
 enum tis_access {
 	TPM_ACCESS_VALID = 0x80,
@@ -293,7 +294,9 @@ static int tpm_tis_send(struct tpm_chip *chip, u8 *buf, size_t len)
 		wait_for_stat(chip, TPM_STS_VALID, chip->vendor.timeout_c,
 			      &chip->vendor.int_queue);
 		status = tpm_tis_status(chip);
-		if ((status & TPM_STS_DATA_EXPECT) == 0) {
+		/* iTPM never sets the DATA_EXPECT bit */
+		if (((status & TPM_STS_DATA_EXPECT) == 0) &&
+		     (!chip->is_itpm)) {
 			rc = -EIO;
 			goto out_err;
 		}
@@ -582,6 +585,12 @@ static int tpm_tis_init(struct device *dev, resource_size_t start,
 	tpm_get_timeouts(chip);
 	tpm_continue_selftest(chip);
 
+	for (i=0; i < 8; i++)
+		if (ITPM_ID[i] != to_pnp_dev(dev)->id->id[i])
+			break;
+	if (i == 8)
+		chip->is_itpm = 1;
+
 	return 0;
 out_err:
 	if (chip->vendor.iobase)
-- 
1.6.3.1






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