linux-kernel - [PATCH] ipmi: Remove ACPI SPMI probing from the SSIF (I2C) driver

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Date:   Thu,  8 Mar 2018 15:08:18 -0600
From:   minyard@....org
To:     Jiandi An <anjiandi@...eaurora.org>
Cc:     openipmi-developer@...ts.sourceforge.net,
        linux-kernel@...r.kernel.org, Corey Minyard <cminyard@...sta.com>
Subject: [PATCH] ipmi: Remove ACPI SPMI probing from the SSIF (I2C) driver

From: Corey Minyard <cminyard@...sta.com>

The IPMI spec states:

  The purpose of the SPMI Table is to provide a mechanism that can
  be used by the OSPM (an ACPI term for “OS Operating System-directed
  configuration and Power Management” essentially meaning an ACPI-aware
  OS or OS loader) very early in the boot process, e.g., before the
  ability to execute ACPI control methods in the OS is available.

When we are probing IPMI in Linux, ACPI control methods are available,
so we shouldn't be probing using SPMI.  It could cause some confusion
during the probing process.

Signed-off-by: Corey Minyard <cminyard@...sta.com>
Cc: Jiandi An <anjiandi@...eaurora.org>
---

Jiandi, this just yanks out the SPMI code.  Your platform
should have an ACPI control method in it's namespace specifying the
IPMI interface.  If it doesn't, that's a bug in your platform and
really needs to be fixed.  Finding IPMI devices with SMBIOS tables
is kind of risky since there is no real way to know which I2C bus
has the IPMI device if your system has more than one I2C bus.  With
an ACPI control method, the IPMI control method will be inside the
I2C bus control method, so it will be unambiguous.

 drivers/char/ipmi/ipmi_ssif.c | 105 ------------------------------------------
 1 file changed, 105 deletions(-)

diff --git a/drivers/char/ipmi/ipmi_ssif.c b/drivers/char/ipmi/ipmi_ssif.c
index 4cff4cd..206257b 100644
--- a/drivers/char/ipmi/ipmi_ssif.c
+++ b/drivers/char/ipmi/ipmi_ssif.c
@@ -1994,108 +1994,6 @@ static const struct acpi_device_id ssif_acpi_match[] = {
 	{ },
 };
 MODULE_DEVICE_TABLE(acpi, ssif_acpi_match);
-
-/*
- * Once we get an ACPI failure, we don't try any more, because we go
- * through the tables sequentially.  Once we don't find a table, there
- * are no more.
- */
-static int acpi_failure;
-
-/*
- * Defined in the IPMI 2.0 spec.
- */
-struct SPMITable {
-	s8	Signature[4];
-	u32	Length;
-	u8	Revision;
-	u8	Checksum;
-	s8	OEMID[6];
-	s8	OEMTableID[8];
-	s8	OEMRevision[4];
-	s8	CreatorID[4];
-	s8	CreatorRevision[4];
-	u8	InterfaceType;
-	u8	IPMIlegacy;
-	s16	SpecificationRevision;
-
-	/*
-	 * Bit 0 - SCI interrupt supported
-	 * Bit 1 - I/O APIC/SAPIC
-	 */
-	u8	InterruptType;
-
-	/*
-	 * If bit 0 of InterruptType is set, then this is the SCI
-	 * interrupt in the GPEx_STS register.
-	 */
-	u8	GPE;
-
-	s16	Reserved;
-
-	/*
-	 * If bit 1 of InterruptType is set, then this is the I/O
-	 * APIC/SAPIC interrupt.
-	 */
-	u32	GlobalSystemInterrupt;
-
-	/* The actual register address. */
-	struct acpi_generic_address addr;
-
-	u8	UID[4];
-
-	s8      spmi_id[1]; /* A '\0' terminated array starts here. */
-};
-
-static int try_init_spmi(struct SPMITable *spmi)
-{
-	unsigned short myaddr;
-
-	if (num_addrs >= MAX_SSIF_BMCS)
-		return -1;
-
-	if (spmi->IPMIlegacy != 1) {
-		pr_warn("IPMI: Bad SPMI legacy: %d\n", spmi->IPMIlegacy);
-		return -ENODEV;
-	}
-
-	if (spmi->InterfaceType != 4)
-		return -ENODEV;
-
-	if (spmi->addr.space_id != ACPI_ADR_SPACE_SMBUS) {
-		pr_warn(PFX "Invalid ACPI SSIF I/O Address type: %d\n",
-			spmi->addr.space_id);
-		return -EIO;
-	}
-
-	myaddr = spmi->addr.address & 0x7f;
-
-	return new_ssif_client(myaddr, NULL, 0, 0, SI_SPMI, NULL);
-}
-
-static void spmi_find_bmc(void)
-{
-	acpi_status      status;
-	struct SPMITable *spmi;
-	int              i;
-
-	if (acpi_disabled)
-		return;
-
-	if (acpi_failure)
-		return;
-
-	for (i = 0; ; i++) {
-		status = acpi_get_table(ACPI_SIG_SPMI, i+1,
-					(struct acpi_table_header **)&spmi);
-		if (status != AE_OK)
-			return;
-
-		try_init_spmi(spmi);
-	}
-}
-#else
-static void spmi_find_bmc(void) { }
 #endif
 
 #ifdef CONFIG_DMI
@@ -2200,9 +2098,6 @@ static int init_ipmi_ssif(void)
 		ssif_i2c_driver.driver.acpi_match_table	=
 			ACPI_PTR(ssif_acpi_match);
 
-	if (ssif_tryacpi)
-		spmi_find_bmc();
-
 	if (ssif_trydmi) {
 		rv = platform_driver_register(&ipmi_driver);
 		if (rv)
-- 
2.7.4