Date:	Fri, 15 May 2009 14:22:21 +0200
From:	Borislav Petkov <borislav.petkov@....com>
To:	<akpm@...ux-foundation.org>, <greg@...ah.com>, <mingo@...e.hu>
CC:	<norsk5@...oo.com>, <tglx@...utronix.de>, <hpa@...or.com>,
	<mchehab@...hat.com>, <aris@...hat.com>, edt@....ca,
	<linux-kernel@...r.kernel.org>,
	Doug Thompson <dougthompson@...ssion.com>,
	Borislav Petkov <borislav.petkov@....com>
Subject: [PATCH 10/22] amd64_edac: add DRAM address type conversion facilities

From: Doug Thompson <dougthompson@...ssion.com>

Borislav:

- cleanup/fix comments, add BKDG refs
- fix function return value patterns
- cleanup dbg calls

Reviewed-by: Mauro Carvalho Chehab <mchehab@...hat.com>
Signed-off-by: Doug Thompson <dougthompson@...ssion.com>
Signed-off-by: Borislav Petkov <borislav.petkov@....com>
---
 drivers/edac/amd64_edac.c |  294 +++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 294 insertions(+), 0 deletions(-)

diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c
index 4716fb5..28f85c9 100644
--- a/drivers/edac/amd64_edac.c
+++ b/drivers/edac/amd64_edac.c
@@ -434,4 +434,298 @@ int amd64_get_dram_hole_info(struct mem_ctl_info *mci, u64 *hole_base,
 }
 EXPORT_SYMBOL_GPL(amd64_get_dram_hole_info);
 
+/*
+ * Return the DramAddr that the SysAddr given by @sys_addr maps to.  It is
+ * assumed that sys_addr maps to the node given by mci.
+ *
+ * The first part of section 3.4.4 (p. 70) shows how the DRAM Base (section
+ * 3.4.4.1) and DRAM Limit (section 3.4.4.2) registers are used to translate a
+ * SysAddr to a DramAddr. If the DRAM Hole Address Register (DHAR) is enabled,
+ * then it is also involved in translating a SysAddr to a DramAddr. Sections
+ * 3.4.8 and 3.5.8.2 describe the DHAR and how it is used for memory hoisting.
+ * These parts of the documentation are unclear. I interpret them as follows:
+ *
+ * When node n receives a SysAddr, it processes the SysAddr as follows:
+ *
+ * 1. It extracts the DRAMBase and DRAMLimit values from the DRAM Base and DRAM
+ *    Limit registers for node n. If the SysAddr is not within the range
+ *    specified by the base and limit values, then node n ignores the Sysaddr
+ *    (since it does not map to node n). Otherwise continue to step 2 below.
+ *
+ * 2. If the DramHoleValid bit of the DHAR for node n is clear, the DHAR is
+ *    disabled so skip to step 3 below. Otherwise see if the SysAddr is within
+ *    the range of relocated addresses (starting at 0x100000000) from the DRAM
+ *    hole. If not, skip to step 3 below. Else get the value of the
+ *    DramHoleOffset field from the DHAR. To obtain the DramAddr, subtract the
+ *    offset defined by this value from the SysAddr.
+ *
+ * 3. Obtain the base address for node n from the DRAMBase field of the DRAM
+ *    Base register for node n. To obtain the DramAddr, subtract the base
+ *    address from the SysAddr, as shown near the start of section 3.4.4 (p.70).
+ */
+static u64 sys_addr_to_dram_addr(struct mem_ctl_info *mci, u64 sys_addr)
+{
+	u64 dram_base, hole_base, hole_offset, hole_size, dram_addr;
+	int ret = 0;
+
+	dram_base = get_dram_base(mci);
+
+	ret = amd64_get_dram_hole_info(mci, &hole_base, &hole_offset,
+				      &hole_size);
+	if (!ret) {
+		if ((sys_addr >= (1ull << 32)) &&
+		    (sys_addr < ((1ull << 32) + hole_size))) {
+			/* use DHAR to translate SysAddr to DramAddr */
+			dram_addr = sys_addr - hole_offset;
+
+			debugf2("using DHAR to translate SysAddr 0x%lx to "
+				"DramAddr 0x%lx\n",
+				(unsigned long)sys_addr,
+				(unsigned long)dram_addr);
+
+			return dram_addr;
+		}
+	}
+
+	/*
+	 * Translate the SysAddr to a DramAddr as shown near the start of
+	 * section 3.4.4 (p. 70).  Although sys_addr is a 64-bit value, the k8
+	 * only deals with 40-bit values.  Therefore we discard bits 63-40 of
+	 * sys_addr below.  If bit 39 of sys_addr is 1 then the bits we
+	 * discard are all 1s.  Otherwise the bits we discard are all 0s.  See
+	 * section 3.4.2 of AMD publication 24592: AMD x86-64 Architecture
+	 * Programmer's Manual Volume 1 Application Programming.
+	 */
+	dram_addr = (sys_addr & 0xffffffffffull) - dram_base;
+
+	debugf2("using DRAM Base register to translate SysAddr 0x%lx to "
+		"DramAddr 0x%lx\n", (unsigned long)sys_addr,
+		(unsigned long)dram_addr);
+	return dram_addr;
+}
+
+/*
+ * @intlv_en is the value of the IntlvEn field from a DRAM Base register
+ * (section 3.4.4.1).  Return the number of bits from a SysAddr that are used
+ * for node interleaving.
+ */
+static int num_node_interleave_bits(unsigned intlv_en)
+{
+	static const int intlv_shift_table[] = { 0, 1, 0, 2, 0, 0, 0, 3 };
+	int n;
+
+	BUG_ON(intlv_en > 7);
+	n = intlv_shift_table[intlv_en];
+	return n;
+}
+
+/* Translate the DramAddr given by @dram_addr to an InputAddr. */
+static u64 dram_addr_to_input_addr(struct mem_ctl_info *mci, u64 dram_addr)
+{
+	struct amd64_pvt *pvt;
+	int intlv_shift;
+	u64 input_addr;
+
+	pvt = mci->pvt_info;
+
+	/*
+	 * See the start of section 3.4.4 (p. 70, BKDG #26094, K8, revA-E)
+	 * concerning translating a DramAddr to an InputAddr.
+	 */
+	intlv_shift = num_node_interleave_bits(pvt->dram_IntlvEn[0]);
+	input_addr = ((dram_addr >> intlv_shift) & 0xffffff000ull) +
+	    (dram_addr & 0xfff);
+
+	debugf2("  Intlv Shift=%d DramAddr=0x%lx maps to InputAddr=0x%lx\n",
+		intlv_shift, (unsigned long)dram_addr,
+		(unsigned long)input_addr);
+
+	return input_addr;
+}
+
+/*
+ * Translate the SysAddr represented by @sys_addr to an InputAddr.  It is
+ * assumed that @sys_addr maps to the node given by mci.
+ */
+static u64 sys_addr_to_input_addr(struct mem_ctl_info *mci, u64 sys_addr)
+{
+	u64 input_addr;
+
+	input_addr =
+	    dram_addr_to_input_addr(mci, sys_addr_to_dram_addr(mci, sys_addr));
+
+	debugf2("SysAdddr 0x%lx translates to InputAddr 0x%lx\n",
+		(unsigned long)sys_addr, (unsigned long)input_addr);
+
+	return input_addr;
+}
+
+
+/*
+ * @input_addr is an InputAddr associated with the node represented by mci.
+ * Translate @input_addr to a DramAddr and return the result.
+ */
+static u64 input_addr_to_dram_addr(struct mem_ctl_info *mci, u64 input_addr)
+{
+	struct amd64_pvt *pvt;
+	int node_id, intlv_shift;
+	u64 bits, dram_addr;
+	u32 intlv_sel;
+
+	/*
+	 * Near the start of section 3.4.4 (p. 70, BKDG #26094, K8, revA-E)
+	 * shows how to translate a DramAddr to an InputAddr. Here we reverse
+	 * this procedure. When translating from a DramAddr to an InputAddr, the
+	 * bits used for node interleaving are discarded.  Here we recover these
+	 * bits from the IntlvSel field of the DRAM Limit register (section
+	 * 3.4.4.2) for the node that input_addr is associated with.
+	 */
+	pvt = mci->pvt_info;
+	node_id = pvt->mc_node_id;
+	BUG_ON((node_id < 0) || (node_id > 7));
+
+	intlv_shift = num_node_interleave_bits(pvt->dram_IntlvEn[0]);
+
+	if (intlv_shift == 0) {
+		debugf1("    InputAddr 0x%lx translates to DramAddr of "
+			"same value\n",	(unsigned long)input_addr);
+
+		return input_addr;
+	}
+
+	bits = ((input_addr & 0xffffff000ull) << intlv_shift) +
+	    (input_addr & 0xfff);
+
+	intlv_sel = pvt->dram_IntlvSel[node_id] & ((1 << intlv_shift) - 1);
+	dram_addr = bits + (intlv_sel << 12);
+
+	debugf1("InputAddr 0x%lx translates to DramAddr 0x%lx "
+		"(%d node interleave bits)\n", (unsigned long)input_addr,
+		(unsigned long)dram_addr, intlv_shift);
+
+	return dram_addr;
+}
+
+/*
+ * @dram_addr is a DramAddr that maps to the node represented by mci. Convert
+ * @dram_addr to a SysAddr.
+ */
+static u64 dram_addr_to_sys_addr(struct mem_ctl_info *mci, u64 dram_addr)
+{
+	struct amd64_pvt *pvt = mci->pvt_info;
+	u64 hole_base, hole_offset, hole_size, base, limit, sys_addr;
+	int ret = 0;
+
+	ret = amd64_get_dram_hole_info(mci, &hole_base, &hole_offset,
+				      &hole_size);
+	if (!ret) {
+		if ((dram_addr >= hole_base) &&
+		    (dram_addr < (hole_base + hole_size))) {
+			sys_addr = dram_addr + hole_offset;
+
+			debugf1("using DHAR to translate DramAddr 0x%lx to "
+				"SysAddr 0x%lx\n", (unsigned long)dram_addr,
+				(unsigned long)sys_addr);
+
+			return sys_addr;
+		}
+	}
+
+	amd64_get_base_and_limit(pvt, pvt->mc_node_id, &base, &limit);
+	sys_addr = dram_addr + base;
+
+	/*
+	 * The sys_addr we have computed up to this point is a 40-bit value
+	 * because the k8 deals with 40-bit values.  However, the value we are
+	 * supposed to return is a full 64-bit physical address.  The AMD
+	 * x86-64 architecture specifies that the most significant implemented
+	 * address bit through bit 63 of a physical address must be either all
+	 * 0s or all 1s.  Therefore we sign-extend the 40-bit sys_addr to a
+	 * 64-bit value below.  See section 3.4.2 of AMD publication 24592:
+	 * AMD x86-64 Architecture Programmer's Manual Volume 1 Application
+	 * Programming.
+	 */
+	sys_addr |= ~((sys_addr & (1ull << 39)) - 1);
+
+	debugf1("    Node %d, DramAddr 0x%lx to SysAddr 0x%lx\n",
+		pvt->mc_node_id, (unsigned long)dram_addr,
+		(unsigned long)sys_addr);
+
+	return sys_addr;
+}
+
+/*
+ * @input_addr is an InputAddr associated with the node given by mci. Translate
+ * @input_addr to a SysAddr.
+ */
+static inline u64 input_addr_to_sys_addr(struct mem_ctl_info *mci,
+					 u64 input_addr)
+{
+	return dram_addr_to_sys_addr(mci,
+				     input_addr_to_dram_addr(mci, input_addr));
+}
+
+/*
+ * Find the minimum and maximum InputAddr values that map to the given @csrow.
+ * Pass back these values in *input_addr_min and *input_addr_max.
+ */
+static void find_csrow_limits(struct mem_ctl_info *mci, int csrow,
+			      u64 *input_addr_min, u64 *input_addr_max)
+{
+	struct amd64_pvt *pvt;
+	u64 base, mask;
+
+	pvt = mci->pvt_info;
+	BUG_ON((csrow < 0) || (csrow >= CHIPSELECT_COUNT));
+
+	base = base_from_dct_base(pvt, csrow);
+	mask = mask_from_dct_mask(pvt, csrow);
+
+	*input_addr_min = base & ~mask;
+	*input_addr_max = base | mask | pvt->dcs_mask_notused;
+}
+
+/*
+ * Extract error address from MCA NB Address Low (section 3.6.4.5) and MCA NB
+ * Address High (section 3.6.4.6) register values and return the result. Address
+ * is located in the info structure (nbeah and nbeal), the encoding is device
+ * specific.
+ */
+static u64 extract_error_address(struct mem_ctl_info *mci,
+				 struct amd64_error_info_regs *info)
+{
+	struct amd64_pvt *pvt = mci->pvt_info;
+
+	return pvt->ops->get_error_address(mci, info);
+}
+
+
+/* Map the Error address to a PAGE and PAGE OFFSET. */
+static inline void error_address_to_page_and_offset(u64 error_address,
+						    u32 *page, u32 *offset)
+{
+	*page = (u32) (error_address >> PAGE_SHIFT);
+	*offset = ((u32) error_address) & ~PAGE_MASK;
+}
+
+/*
+ * @sys_addr is an error address (a SysAddr) extracted from the MCA NB Address
+ * Low (section 3.6.4.5) and MCA NB Address High (section 3.6.4.6) registers
+ * of a node that detected an ECC memory error.  mci represents the node that
+ * the error address maps to (possibly different from the node that detected
+ * the error).  Return the number of the csrow that sys_addr maps to, or -1 on
+ * error.
+ */
+static int sys_addr_to_csrow(struct mem_ctl_info *mci, u64 sys_addr)
+{
+	int csrow;
+
+	csrow = input_addr_to_csrow(mci, sys_addr_to_input_addr(mci, sys_addr));
+
+	if (csrow == -1)
+		amd64_mc_printk(mci, KERN_ERR,
+			     "Failed to translate InputAddr to csrow for "
+			     "address 0x%lx\n", (unsigned long)sys_addr);
+	return csrow;
+}
 
-- 
1.6.2.4


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