[PATCH] IOSF: Add interface for the cases requiring fid

[Fei Yang]

From: Fei Yang <fei.yang@xxxxxxxxx>

Some implementations may require an additional step for setting the FID
bits to ensure correct transactions over the IOSF side band interface.
Add the FID support accordingly for such implementations

Change-Id: Ic0227f9e74133a3203aa08e8471939f905d19622
Signed-off-by: Fei Yang <fei.yang@xxxxxxxxx>
---
 arch/x86/include/asm/iosf_mbi.h    | 27 ++++++++++++++
 arch/x86/platform/intel/iosf_mbi.c | 73 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 100 insertions(+)

diff --git a/arch/x86/include/asm/iosf_mbi.h b/arch/x86/include/asm/iosf_mbi.h
index b41ee16..71511ba 100644
--- a/arch/x86/include/asm/iosf_mbi.h
+++ b/arch/x86/include/asm/iosf_mbi.h
@@ -8,6 +8,7 @@
 #define MBI_MCR_OFFSET		0xD0
 #define MBI_MDR_OFFSET		0xD4
 #define MBI_MCRX_OFFSET		0xD8
+#define MBI_MCRP_OFFSET		0xDC
 
 #define MBI_RD_MASK		0xFEFFFFFF
 #define MBI_WR_MASK		0X01000000
@@ -88,6 +89,32 @@ int iosf_mbi_write(u8 port, u8 opcode, u32 offset, u32 mdr);
  */
 int iosf_mbi_modify(u8 port, u8 opcode, u32 offset, u32 mdr, u32 mask);
 
+/**
+ * iosf_mbi_read_with_fid() - MailBox Interface read command requiring fid
+ * @fid:	fid bits
+ * @port:	port indicating subunit being accessed
+ * @opcode:	port specific read or write opcode
+ * @offset:	register address offset
+ * @mdr:	register data to be read
+ *
+ * Locking is handled by spinlock - cannot sleep.
+ * Return: Nonzero on error
+ */
+int iosf_mbi_read_with_fid(u32 fid, u8 port, u8 opcode, u32 offset, u32 *mdr);
+
+/**
+ * iosf_mbi_write_with_fid() - MailBox unmasked write command requiring fid
+ * @fid:	fid bits
+ * @port:	port indicating subunit being accessed
+ * @opcode:	port specific read or write opcode
+ * @offset:	register address offset
+ * @mdr:	register data to be written
+ *
+ * Locking is handled by spinlock - cannot sleep.
+ * Return: Nonzero on error
+ */
+int iosf_mbi_write_with_fid(u32 fid, u8 port, u8 opcode, u32 offset, u32 mdr);
+
 #else /* CONFIG_IOSF_MBI is not enabled */
 static inline
 bool iosf_mbi_available(void)
diff --git a/arch/x86/platform/intel/iosf_mbi.c b/arch/x86/platform/intel/iosf_mbi.c
index edf2c54..af182c1 100644
--- a/arch/x86/platform/intel/iosf_mbi.c
+++ b/arch/x86/platform/intel/iosf_mbi.c
@@ -98,6 +98,24 @@ fail_write:
 	return result;
 }
 
+static int iosf_mbi_pci_write_fid(u32 fid)
+{
+	int result;
+
+	if (!mbi_pdev)
+		return -ENODEV;
+
+	result = pci_write_config_dword(mbi_pdev, MBI_MCRP_OFFSET, fid);
+	if (result < 0)
+		goto fail_fid_write;
+
+	return 0;
+
+fail_fid_write:
+	dev_err(&mbi_pdev->dev, "PCI config access failed with %d\n", result);
+	return result;
+}
+
 int iosf_mbi_read(u8 port, u8 opcode, u32 offset, u32 *mdr)
 {
 	u32 mcr, mcrx;
@@ -183,6 +201,61 @@ int iosf_mbi_modify(u8 port, u8 opcode, u32 offset, u32 mdr, u32 mask)
 }
 EXPORT_SYMBOL(iosf_mbi_modify);
 
+/*
+ * Some IP blocks require fid to access their registers.
+ * fid value is programmed through MCRP register, see above function
+ * iosf_mbi_pci_write_fid() for details.
+ */
+int iosf_mbi_read_with_fid(u32 fid, u8 port, u8 opcode, u32 offset, u32 *mdr)
+{
+	u32 mcr, mcrx;
+	unsigned long flags;
+	int ret;
+
+	/*Access to the GFX unit is handled by GPU code */
+	if (port == BT_MBI_UNIT_GFX) {
+		WARN_ON(1);
+		return -EPERM;
+	}
+
+	mcr = iosf_mbi_form_mcr(opcode, port, offset & MBI_MASK_LO);
+	mcrx = offset & MBI_MASK_HI;
+
+	spin_lock_irqsave(&iosf_mbi_lock, flags);
+	ret = iosf_mbi_pci_write_fid(fid);
+	if (!ret)
+		ret = iosf_mbi_pci_read_mdr(mcrx, mcr, mdr);
+	spin_unlock_irqrestore(&iosf_mbi_lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL(iosf_mbi_read_with_fid);
+
+int iosf_mbi_write_with_fid(u32 fid, u8 port, u8 opcode, u32 offset, u32 mdr)
+{
+	u32 mcr, mcrx;
+	unsigned long flags;
+	int ret;
+
+	/*Access to the GFX unit is handled by GPU code */
+	if (port == BT_MBI_UNIT_GFX) {
+		WARN_ON(1);
+		return -EPERM;
+	}
+
+	mcr = iosf_mbi_form_mcr(opcode, port, offset & MBI_MASK_LO);
+	mcrx = offset & MBI_MASK_HI;
+
+	spin_lock_irqsave(&iosf_mbi_lock, flags);
+	ret = iosf_mbi_pci_write_fid(fid);
+	if (!ret)
+		ret = iosf_mbi_pci_write_mdr(mcrx, mcr, mdr);
+	spin_unlock_irqrestore(&iosf_mbi_lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL(iosf_mbi_write_with_fid);
+
 bool iosf_mbi_available(void)
 {
 	/* Mbi isn't hot-pluggable. No remove routine is provided */
-- 
1.9.1