1/*
2 *  Linux MegaRAID driver for SAS based RAID controllers
3 *
4 *  Copyright (c) 2009-2011  LSI Corporation.
5 *
6 *  This program is free software; you can redistribute it and/or
7 *  modify it under the terms of the GNU General Public License
8 *  as published by the Free Software Foundation; either version 2
9 *  of the License, or (at your option) any later version.
10 *
11 *  This program is distributed in the hope that it will be useful,
12 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
13 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14 *  GNU General Public License for more details.
15 *
16 *  You should have received a copy of the GNU General Public License
17 *  along with this program; if not, write to the Free Software
18 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19 *
20 *  FILE: megaraid_sas_fp.c
21 *
22 *  Authors: LSI Corporation
23 *           Sumant Patro
24 *           Varad Talamacki
25 *           Manoj Jose
26 *
27 *  Send feedback to: <megaraidlinux@lsi.com>
28 *
29 *  Mail to: LSI Corporation, 1621 Barber Lane, Milpitas, CA 95035
30 *     ATTN: Linuxraid
31 */
32
33#include <linux/kernel.h>
34#include <linux/types.h>
35#include <linux/pci.h>
36#include <linux/list.h>
37#include <linux/moduleparam.h>
38#include <linux/module.h>
39#include <linux/spinlock.h>
40#include <linux/interrupt.h>
41#include <linux/delay.h>
42#include <linux/uio.h>
43#include <linux/uaccess.h>
44#include <linux/fs.h>
45#include <linux/compat.h>
46#include <linux/blkdev.h>
47#include <linux/poll.h>
48
49#include <scsi/scsi.h>
50#include <scsi/scsi_cmnd.h>
51#include <scsi/scsi_device.h>
52#include <scsi/scsi_host.h>
53
54#include "megaraid_sas_fusion.h"
55#include "megaraid_sas.h"
56#include <asm/div64.h>
57
58#define ABS_DIFF(a, b)   (((a) > (b)) ? ((a) - (b)) : ((b) - (a)))
59#define MR_LD_STATE_OPTIMAL 3
60#define FALSE 0
61#define TRUE 1
62
63/* Prototypes */
64void
65mr_update_load_balance_params(struct MR_FW_RAID_MAP_ALL *map,
66			      struct LD_LOAD_BALANCE_INFO *lbInfo);
67
68u32 mega_mod64(u64 dividend, u32 divisor)
69{
70	u64 d;
71	u32 remainder;
72
73	if (!divisor)
74		printk(KERN_ERR "megasas : DIVISOR is zero, in div fn\n");
75	d = dividend;
76	remainder = do_div(d, divisor);
77	return remainder;
78}
79
80/**
81 * @param dividend    : Dividend
82 * @param divisor    : Divisor
83 *
84 * @return quotient
85 **/
86u64 mega_div64_32(uint64_t dividend, uint32_t divisor)
87{
88	u32 remainder;
89	u64 d;
90
91	if (!divisor)
92		printk(KERN_ERR "megasas : DIVISOR is zero in mod fn\n");
93
94	d = dividend;
95	remainder = do_div(d, divisor);
96
97	return d;
98}
99
100struct MR_LD_RAID *MR_LdRaidGet(u32 ld, struct MR_FW_RAID_MAP_ALL *map)
101{
102	return &map->raidMap.ldSpanMap[ld].ldRaid;
103}
104
105static struct MR_SPAN_BLOCK_INFO *MR_LdSpanInfoGet(u32 ld,
106						   struct MR_FW_RAID_MAP_ALL
107						   *map)
108{
109	return &map->raidMap.ldSpanMap[ld].spanBlock[0];
110}
111
112static u8 MR_LdDataArmGet(u32 ld, u32 armIdx, struct MR_FW_RAID_MAP_ALL *map)
113{
114	return map->raidMap.ldSpanMap[ld].dataArmMap[armIdx];
115}
116
117static u16 MR_ArPdGet(u32 ar, u32 arm, struct MR_FW_RAID_MAP_ALL *map)
118{
119	return map->raidMap.arMapInfo[ar].pd[arm];
120}
121
122static u16 MR_LdSpanArrayGet(u32 ld, u32 span, struct MR_FW_RAID_MAP_ALL *map)
123{
124	return map->raidMap.ldSpanMap[ld].spanBlock[span].span.arrayRef;
125}
126
127static u16 MR_PdDevHandleGet(u32 pd, struct MR_FW_RAID_MAP_ALL *map)
128{
129	return map->raidMap.devHndlInfo[pd].curDevHdl;
130}
131
132u16 MR_GetLDTgtId(u32 ld, struct MR_FW_RAID_MAP_ALL *map)
133{
134	return map->raidMap.ldSpanMap[ld].ldRaid.targetId;
135}
136
137u16 MR_TargetIdToLdGet(u32 ldTgtId, struct MR_FW_RAID_MAP_ALL *map)
138{
139	return map->raidMap.ldTgtIdToLd[ldTgtId];
140}
141
142static struct MR_LD_SPAN *MR_LdSpanPtrGet(u32 ld, u32 span,
143					  struct MR_FW_RAID_MAP_ALL *map)
144{
145	return &map->raidMap.ldSpanMap[ld].spanBlock[span].span;
146}
147
148/*
149 * This function will validate Map info data provided by FW
150 */
151u8 MR_ValidateMapInfo(struct MR_FW_RAID_MAP_ALL *map,
152		      struct LD_LOAD_BALANCE_INFO *lbInfo)
153{
154	struct MR_FW_RAID_MAP *pFwRaidMap = &map->raidMap;
155
156	if (pFwRaidMap->totalSize !=
157	    (sizeof(struct MR_FW_RAID_MAP) -sizeof(struct MR_LD_SPAN_MAP) +
158	     (sizeof(struct MR_LD_SPAN_MAP) *pFwRaidMap->ldCount))) {
159		printk(KERN_ERR "megasas: map info structure size 0x%x is not matching with ld count\n",
160		       (unsigned int)((sizeof(struct MR_FW_RAID_MAP) -
161				       sizeof(struct MR_LD_SPAN_MAP)) +
162				      (sizeof(struct MR_LD_SPAN_MAP) *
163				       pFwRaidMap->ldCount)));
164		printk(KERN_ERR "megasas: span map %x, pFwRaidMap->totalSize "
165		       ": %x\n", (unsigned int)sizeof(struct MR_LD_SPAN_MAP),
166		       pFwRaidMap->totalSize);
167		return 0;
168	}
169
170	mr_update_load_balance_params(map, lbInfo);
171
172	return 1;
173}
174
175u32 MR_GetSpanBlock(u32 ld, u64 row, u64 *span_blk,
176		    struct MR_FW_RAID_MAP_ALL *map, int *div_error)
177{
178	struct MR_SPAN_BLOCK_INFO *pSpanBlock = MR_LdSpanInfoGet(ld, map);
179	struct MR_QUAD_ELEMENT    *quad;
180	struct MR_LD_RAID         *raid = MR_LdRaidGet(ld, map);
181	u32                span, j;
182
183	for (span = 0; span < raid->spanDepth; span++, pSpanBlock++) {
184
185		for (j = 0; j < pSpanBlock->block_span_info.noElements; j++) {
186			quad = &pSpanBlock->block_span_info.quad[j];
187
188			if (quad->diff == 0) {
189				*div_error = 1;
190				return span;
191			}
192			if (quad->logStart <= row  &&  row <= quad->logEnd  &&
193			    (mega_mod64(row-quad->logStart, quad->diff)) == 0) {
194				if (span_blk != NULL) {
195					u64  blk, debugBlk;
196					blk =
197						mega_div64_32(
198							(row-quad->logStart),
199							quad->diff);
200					debugBlk = blk;
201
202					blk = (blk + quad->offsetInSpan) <<
203						raid->stripeShift;
204					*span_blk = blk;
205				}
206				return span;
207			}
208		}
209	}
210	return span;
211}
212
213/*
214******************************************************************************
215*
216* This routine calculates the arm, span and block for the specified stripe and
217* reference in stripe.
218*
219* Inputs :
220*
221*    ld   - Logical drive number
222*    stripRow        - Stripe number
223*    stripRef    - Reference in stripe
224*
225* Outputs :
226*
227*    span          - Span number
228*    block         - Absolute Block number in the physical disk
229*/
230u8 MR_GetPhyParams(struct megasas_instance *instance, u32 ld, u64 stripRow,
231		   u16 stripRef, u64 *pdBlock, u16 *pDevHandle,
232		   struct RAID_CONTEXT *pRAID_Context,
233		   struct MR_FW_RAID_MAP_ALL *map)
234{
235	struct MR_LD_RAID  *raid = MR_LdRaidGet(ld, map);
236	u32         pd, arRef;
237	u8          physArm, span;
238	u64         row;
239	u8	    retval = TRUE;
240	int	    error_code = 0;
241
242	row =  mega_div64_32(stripRow, raid->rowDataSize);
243
244	if (raid->level == 6) {
245		/* logical arm within row */
246		u32 logArm =  mega_mod64(stripRow, raid->rowDataSize);
247		u32 rowMod, armQ, arm;
248
249		if (raid->rowSize == 0)
250			return FALSE;
251		/* get logical row mod */
252		rowMod = mega_mod64(row, raid->rowSize);
253		armQ = raid->rowSize-1-rowMod; /* index of Q drive */
254		arm = armQ+1+logArm; /* data always logically follows Q */
255		if (arm >= raid->rowSize) /* handle wrap condition */
256			arm -= raid->rowSize;
257		physArm = (u8)arm;
258	} else  {
259		if (raid->modFactor == 0)
260			return FALSE;
261		physArm = MR_LdDataArmGet(ld,  mega_mod64(stripRow,
262							  raid->modFactor),
263					  map);
264	}
265
266	if (raid->spanDepth == 1) {
267		span = 0;
268		*pdBlock = row << raid->stripeShift;
269	} else {
270		span = (u8)MR_GetSpanBlock(ld, row, pdBlock, map, &error_code);
271		if (error_code == 1)
272			return FALSE;
273	}
274
275	/* Get the array on which this span is present */
276	arRef       = MR_LdSpanArrayGet(ld, span, map);
277	pd          = MR_ArPdGet(arRef, physArm, map); /* Get the pd */
278
279	if (pd != MR_PD_INVALID)
280		/* Get dev handle from Pd. */
281		*pDevHandle = MR_PdDevHandleGet(pd, map);
282	else {
283		*pDevHandle = MR_PD_INVALID; /* set dev handle as invalid. */
284		if ((raid->level >= 5) &&
285		    ((instance->pdev->device != PCI_DEVICE_ID_LSI_INVADER) ||
286		     (instance->pdev->device == PCI_DEVICE_ID_LSI_INVADER &&
287		      raid->regTypeReqOnRead != REGION_TYPE_UNUSED)))
288			pRAID_Context->regLockFlags = REGION_TYPE_EXCLUSIVE;
289		else if (raid->level == 1) {
290			/* Get alternate Pd. */
291			pd = MR_ArPdGet(arRef, physArm + 1, map);
292			if (pd != MR_PD_INVALID)
293				/* Get dev handle from Pd */
294				*pDevHandle = MR_PdDevHandleGet(pd, map);
295		}
296	}
297
298	*pdBlock += stripRef + MR_LdSpanPtrGet(ld, span, map)->startBlk;
299	pRAID_Context->spanArm = (span << RAID_CTX_SPANARM_SPAN_SHIFT) |
300		physArm;
301	return retval;
302}
303
304/*
305******************************************************************************
306*
307* MR_BuildRaidContext function
308*
309* This function will initiate command processing.  The start/end row and strip
310* information is calculated then the lock is acquired.
311* This function will return 0 if region lock was acquired OR return num strips
312*/
313u8
314MR_BuildRaidContext(struct megasas_instance *instance,
315		    struct IO_REQUEST_INFO *io_info,
316		    struct RAID_CONTEXT *pRAID_Context,
317		    struct MR_FW_RAID_MAP_ALL *map)
318{
319	struct MR_LD_RAID  *raid;
320	u32         ld, stripSize, stripe_mask;
321	u64         endLba, endStrip, endRow, start_row, start_strip;
322	u64         regStart;
323	u32         regSize;
324	u8          num_strips, numRows;
325	u16         ref_in_start_stripe, ref_in_end_stripe;
326	u64         ldStartBlock;
327	u32         numBlocks, ldTgtId;
328	u8          isRead;
329	u8	    retval = 0;
330
331	ldStartBlock = io_info->ldStartBlock;
332	numBlocks = io_info->numBlocks;
333	ldTgtId = io_info->ldTgtId;
334	isRead = io_info->isRead;
335
336	ld = MR_TargetIdToLdGet(ldTgtId, map);
337	raid = MR_LdRaidGet(ld, map);
338
339	stripSize = 1 << raid->stripeShift;
340	stripe_mask = stripSize-1;
341	/*
342	 * calculate starting row and stripe, and number of strips and rows
343	 */
344	start_strip         = ldStartBlock >> raid->stripeShift;
345	ref_in_start_stripe = (u16)(ldStartBlock & stripe_mask);
346	endLba              = ldStartBlock + numBlocks - 1;
347	ref_in_end_stripe   = (u16)(endLba & stripe_mask);
348	endStrip            = endLba >> raid->stripeShift;
349	num_strips          = (u8)(endStrip - start_strip + 1); /* End strip */
350	if (raid->rowDataSize == 0)
351		return FALSE;
352	start_row           =  mega_div64_32(start_strip, raid->rowDataSize);
353	endRow              =  mega_div64_32(endStrip, raid->rowDataSize);
354	numRows             = (u8)(endRow - start_row + 1);
355
356	/*
357	 * calculate region info.
358	 */
359
360	/* assume region is at the start of the first row */
361	regStart            = start_row << raid->stripeShift;
362	/* assume this IO needs the full row - we'll adjust if not true */
363	regSize             = stripSize;
364
365	/* If IO spans more than 1 strip, fp is not possible
366	   FP is not possible for writes on non-0 raid levels
367	   FP is not possible if LD is not capable */
368	if (num_strips > 1 || (!isRead && raid->level != 0) ||
369	    !raid->capability.fpCapable) {
370		io_info->fpOkForIo = FALSE;
371	} else {
372		io_info->fpOkForIo = TRUE;
373	}
374
375	if (numRows == 1) {
376		/* single-strip IOs can always lock only the data needed */
377		if (num_strips == 1) {
378			regStart += ref_in_start_stripe;
379			regSize = numBlocks;
380		}
381		/* multi-strip IOs always need to full stripe locked */
382	} else {
383		if (start_strip == (start_row + 1) * raid->rowDataSize - 1) {
384			/* If the start strip is the last in the start row */
385			regStart += ref_in_start_stripe;
386			regSize = stripSize - ref_in_start_stripe;
387			/* initialize count to sectors from startref to end
388			   of strip */
389		}
390
391		if (numRows > 2)
392			/* Add complete rows in the middle of the transfer */
393			regSize += (numRows-2) << raid->stripeShift;
394
395		/* if IO ends within first strip of last row */
396		if (endStrip == endRow*raid->rowDataSize)
397			regSize += ref_in_end_stripe+1;
398		else
399			regSize += stripSize;
400	}
401
402	pRAID_Context->timeoutValue     = map->raidMap.fpPdIoTimeoutSec;
403	if (instance->pdev->device == PCI_DEVICE_ID_LSI_INVADER)
404		pRAID_Context->regLockFlags = (isRead) ?
405			raid->regTypeReqOnRead : raid->regTypeReqOnWrite;
406	else
407		pRAID_Context->regLockFlags = (isRead) ?
408			REGION_TYPE_SHARED_READ : raid->regTypeReqOnWrite;
409	pRAID_Context->VirtualDiskTgtId = raid->targetId;
410	pRAID_Context->regLockRowLBA    = regStart;
411	pRAID_Context->regLockLength    = regSize;
412	pRAID_Context->configSeqNum	= raid->seqNum;
413
414	/*Get Phy Params only if FP capable, or else leave it to MR firmware
415	  to do the calculation.*/
416	if (io_info->fpOkForIo) {
417		retval = MR_GetPhyParams(instance, ld, start_strip,
418					 ref_in_start_stripe,
419					 &io_info->pdBlock,
420					 &io_info->devHandle, pRAID_Context,
421					 map);
422		/* If IO on an invalid Pd, then FP i snot possible */
423		if (io_info->devHandle == MR_PD_INVALID)
424			io_info->fpOkForIo = FALSE;
425		return retval;
426	} else if (isRead) {
427		uint stripIdx;
428		for (stripIdx = 0; stripIdx < num_strips; stripIdx++) {
429			if (!MR_GetPhyParams(instance, ld,
430					     start_strip + stripIdx,
431					     ref_in_start_stripe,
432					     &io_info->pdBlock,
433					     &io_info->devHandle,
434					     pRAID_Context, map))
435				return TRUE;
436		}
437	}
438	return TRUE;
439}
440
441void
442mr_update_load_balance_params(struct MR_FW_RAID_MAP_ALL *map,
443			      struct LD_LOAD_BALANCE_INFO *lbInfo)
444{
445	int ldCount;
446	u16 ld;
447	struct MR_LD_RAID *raid;
448
449	for (ldCount = 0; ldCount < MAX_LOGICAL_DRIVES; ldCount++) {
450		ld = MR_TargetIdToLdGet(ldCount, map);
451		if (ld >= MAX_LOGICAL_DRIVES) {
452			lbInfo[ldCount].loadBalanceFlag = 0;
453			continue;
454		}
455
456		raid = MR_LdRaidGet(ld, map);
457
458		/* Two drive Optimal RAID 1 */
459		if ((raid->level == 1)  &&  (raid->rowSize == 2) &&
460		    (raid->spanDepth == 1) && raid->ldState ==
461		    MR_LD_STATE_OPTIMAL) {
462			u32 pd, arRef;
463
464			lbInfo[ldCount].loadBalanceFlag = 1;
465
466			/* Get the array on which this span is present */
467			arRef = MR_LdSpanArrayGet(ld, 0, map);
468
469			/* Get the Pd */
470			pd = MR_ArPdGet(arRef, 0, map);
471			/* Get dev handle from Pd */
472			lbInfo[ldCount].raid1DevHandle[0] =
473				MR_PdDevHandleGet(pd, map);
474			/* Get the Pd */
475			pd = MR_ArPdGet(arRef, 1, map);
476
477			/* Get the dev handle from Pd */
478			lbInfo[ldCount].raid1DevHandle[1] =
479				MR_PdDevHandleGet(pd, map);
480		} else
481			lbInfo[ldCount].loadBalanceFlag = 0;
482	}
483}
484
485u8 megasas_get_best_arm(struct LD_LOAD_BALANCE_INFO *lbInfo, u8 arm, u64 block,
486			u32 count)
487{
488	u16     pend0, pend1;
489	u64     diff0, diff1;
490	u8      bestArm;
491
492	/* get the pending cmds for the data and mirror arms */
493	pend0 = atomic_read(&lbInfo->scsi_pending_cmds[0]);
494	pend1 = atomic_read(&lbInfo->scsi_pending_cmds[1]);
495
496	/* Determine the disk whose head is nearer to the req. block */
497	diff0 = ABS_DIFF(block, lbInfo->last_accessed_block[0]);
498	diff1 = ABS_DIFF(block, lbInfo->last_accessed_block[1]);
499	bestArm = (diff0 <= diff1 ? 0 : 1);
500
501	if ((bestArm == arm && pend0 > pend1 + 16)  ||
502	    (bestArm != arm && pend1 > pend0 + 16))
503		bestArm ^= 1;
504
505	/* Update the last accessed block on the correct pd */
506	lbInfo->last_accessed_block[bestArm] = block + count - 1;
507
508	return bestArm;
509}
510
511u16 get_updated_dev_handle(struct LD_LOAD_BALANCE_INFO *lbInfo,
512			   struct IO_REQUEST_INFO *io_info)
513{
514	u8 arm, old_arm;
515	u16 devHandle;
516
517	old_arm = lbInfo->raid1DevHandle[0] == io_info->devHandle ? 0 : 1;
518
519	/* get best new arm */
520	arm  = megasas_get_best_arm(lbInfo, old_arm, io_info->ldStartBlock,
521				    io_info->numBlocks);
522	devHandle = lbInfo->raid1DevHandle[arm];
523	atomic_inc(&lbInfo->scsi_pending_cmds[arm]);
524
525	return devHandle;
526}
527