xref: /OK3568_Linux_fs/u-boot/arch/arm/mach-omap2/omap4/sdram_elpida.c (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593Smuzhiyun /*
2*4882a593Smuzhiyun  * Timing and Organization details of the Elpida parts used in OMAP4
3*4882a593Smuzhiyun  * SDPs and Panda
4*4882a593Smuzhiyun  *
5*4882a593Smuzhiyun  * (C) Copyright 2010
6*4882a593Smuzhiyun  * Texas Instruments, <www.ti.com>
7*4882a593Smuzhiyun  *
8*4882a593Smuzhiyun  * Aneesh V <aneesh@ti.com>
9*4882a593Smuzhiyun  *
10*4882a593Smuzhiyun  * SPDX-License-Identifier:	GPL-2.0+
11*4882a593Smuzhiyun  */
12*4882a593Smuzhiyun 
13*4882a593Smuzhiyun #include <asm/emif.h>
14*4882a593Smuzhiyun #include <asm/arch/sys_proto.h>
15*4882a593Smuzhiyun 
16*4882a593Smuzhiyun /*
17*4882a593Smuzhiyun  * This file provides details of the LPDDR2 SDRAM parts used on OMAP4430
18*4882a593Smuzhiyun  * SDP and Panda. Since the parts used and geometry are identical for
19*4882a593Smuzhiyun  * SDP and Panda for a given OMAP4 revision, this information is kept
20*4882a593Smuzhiyun  * here instead of being in board directory. However the key functions
21*4882a593Smuzhiyun  * exported are weakly linked so that they can be over-ridden in the board
22*4882a593Smuzhiyun  * directory if there is a OMAP4 board in the future that uses a different
23*4882a593Smuzhiyun  * memory device or geometry.
24*4882a593Smuzhiyun  *
25*4882a593Smuzhiyun  * For any new board with different memory devices over-ride one or more
26*4882a593Smuzhiyun  * of the following functions as per the CONFIG flags you intend to enable:
27*4882a593Smuzhiyun  * - emif_get_reg_dump()
28*4882a593Smuzhiyun  * - emif_get_dmm_regs()
29*4882a593Smuzhiyun  * - emif_get_device_details()
30*4882a593Smuzhiyun  * - emif_get_device_timings()
31*4882a593Smuzhiyun  */
32*4882a593Smuzhiyun 
33*4882a593Smuzhiyun #ifdef CONFIG_SYS_EMIF_PRECALCULATED_TIMING_REGS
34*4882a593Smuzhiyun 
35*4882a593Smuzhiyun const struct emif_regs emif_regs_elpida_200_mhz_2cs = {
36*4882a593Smuzhiyun 	.sdram_config_init		= 0x80000eb9,
37*4882a593Smuzhiyun 	.sdram_config			= 0x80001ab9,
38*4882a593Smuzhiyun 	.ref_ctrl			= 0x0000030c,
39*4882a593Smuzhiyun 	.sdram_tim1			= 0x08648311,
40*4882a593Smuzhiyun 	.sdram_tim2			= 0x101b06ca,
41*4882a593Smuzhiyun 	.sdram_tim3			= 0x0048a19f,
42*4882a593Smuzhiyun 	.read_idle_ctrl			= 0x000501ff,
43*4882a593Smuzhiyun 	.zq_config			= 0x500b3214,
44*4882a593Smuzhiyun 	.temp_alert_config		= 0xd8016893,
45*4882a593Smuzhiyun 	.emif_ddr_phy_ctlr_1_init	= 0x049ffff5,
46*4882a593Smuzhiyun 	.emif_ddr_phy_ctlr_1		= 0x049ff808
47*4882a593Smuzhiyun };
48*4882a593Smuzhiyun 
49*4882a593Smuzhiyun const struct emif_regs emif_regs_elpida_380_mhz_1cs = {
50*4882a593Smuzhiyun 	.sdram_config_init		= 0x80000eb1,
51*4882a593Smuzhiyun 	.sdram_config			= 0x80001ab1,
52*4882a593Smuzhiyun 	.ref_ctrl			= 0x000005cd,
53*4882a593Smuzhiyun 	.sdram_tim1			= 0x10cb0622,
54*4882a593Smuzhiyun 	.sdram_tim2			= 0x20350d52,
55*4882a593Smuzhiyun 	.sdram_tim3			= 0x00b1431f,
56*4882a593Smuzhiyun 	.read_idle_ctrl			= 0x000501ff,
57*4882a593Smuzhiyun 	.zq_config			= 0x500b3214,
58*4882a593Smuzhiyun 	.temp_alert_config		= 0x58016893,
59*4882a593Smuzhiyun 	.emif_ddr_phy_ctlr_1_init	= 0x049ffff5,
60*4882a593Smuzhiyun 	.emif_ddr_phy_ctlr_1		= 0x049ff418
61*4882a593Smuzhiyun };
62*4882a593Smuzhiyun 
63*4882a593Smuzhiyun const struct emif_regs emif_regs_elpida_400_mhz_1cs = {
64*4882a593Smuzhiyun 	.sdram_config_init		= 0x80800eb2,
65*4882a593Smuzhiyun 	.sdram_config			= 0x80801ab2,
66*4882a593Smuzhiyun 	.ref_ctrl			= 0x00000618,
67*4882a593Smuzhiyun 	.sdram_tim1			= 0x10eb0662,
68*4882a593Smuzhiyun 	.sdram_tim2			= 0x20370dd2,
69*4882a593Smuzhiyun 	.sdram_tim3			= 0x00b1c33f,
70*4882a593Smuzhiyun 	.read_idle_ctrl			= 0x000501ff,
71*4882a593Smuzhiyun 	.zq_config			= 0x500b3215,
72*4882a593Smuzhiyun 	.temp_alert_config		= 0x58016893,
73*4882a593Smuzhiyun 	.emif_ddr_phy_ctlr_1_init	= 0x049ffff5,
74*4882a593Smuzhiyun 	.emif_ddr_phy_ctlr_1		= 0x049ff418
75*4882a593Smuzhiyun };
76*4882a593Smuzhiyun 
77*4882a593Smuzhiyun const struct emif_regs emif_regs_elpida_400_mhz_2cs = {
78*4882a593Smuzhiyun 	.sdram_config_init		= 0x80000eb9,
79*4882a593Smuzhiyun 	.sdram_config			= 0x80001ab9,
80*4882a593Smuzhiyun 	.ref_ctrl			= 0x00000618,
81*4882a593Smuzhiyun 	.sdram_tim1			= 0x10eb0662,
82*4882a593Smuzhiyun 	.sdram_tim2			= 0x20370dd2,
83*4882a593Smuzhiyun 	.sdram_tim3			= 0x00b1c33f,
84*4882a593Smuzhiyun 	.read_idle_ctrl			= 0x000501ff,
85*4882a593Smuzhiyun 	.zq_config			= 0xd00b3214,
86*4882a593Smuzhiyun 	.temp_alert_config		= 0xd8016893,
87*4882a593Smuzhiyun 	.emif_ddr_phy_ctlr_1_init	= 0x049ffff5,
88*4882a593Smuzhiyun 	.emif_ddr_phy_ctlr_1		= 0x049ff418
89*4882a593Smuzhiyun };
90*4882a593Smuzhiyun 
91*4882a593Smuzhiyun const struct dmm_lisa_map_regs lisa_map_2G_x_1_x_2 = {
92*4882a593Smuzhiyun 	.dmm_lisa_map_0 = 0xFF020100,
93*4882a593Smuzhiyun 	.dmm_lisa_map_1 = 0,
94*4882a593Smuzhiyun 	.dmm_lisa_map_2 = 0,
95*4882a593Smuzhiyun 	.dmm_lisa_map_3 = 0x80540300,
96*4882a593Smuzhiyun 	.is_ma_present	= 0x0
97*4882a593Smuzhiyun };
98*4882a593Smuzhiyun 
99*4882a593Smuzhiyun const struct dmm_lisa_map_regs lisa_map_2G_x_2_x_2 = {
100*4882a593Smuzhiyun 	.dmm_lisa_map_0 = 0xFF020100,
101*4882a593Smuzhiyun 	.dmm_lisa_map_1 = 0,
102*4882a593Smuzhiyun 	.dmm_lisa_map_2 = 0,
103*4882a593Smuzhiyun 	.dmm_lisa_map_3 = 0x80640300,
104*4882a593Smuzhiyun 	.is_ma_present	= 0x0
105*4882a593Smuzhiyun };
106*4882a593Smuzhiyun 
107*4882a593Smuzhiyun const struct dmm_lisa_map_regs ma_lisa_map_2G_x_2_x_2 = {
108*4882a593Smuzhiyun 	.dmm_lisa_map_0 = 0xFF020100,
109*4882a593Smuzhiyun 	.dmm_lisa_map_1 = 0,
110*4882a593Smuzhiyun 	.dmm_lisa_map_2 = 0,
111*4882a593Smuzhiyun 	.dmm_lisa_map_3 = 0x80640300,
112*4882a593Smuzhiyun 	.is_ma_present	= 0x1
113*4882a593Smuzhiyun };
114*4882a593Smuzhiyun 
emif_get_reg_dump_sdp(u32 emif_nr,const struct emif_regs ** regs)115*4882a593Smuzhiyun static void emif_get_reg_dump_sdp(u32 emif_nr, const struct emif_regs **regs)
116*4882a593Smuzhiyun {
117*4882a593Smuzhiyun 	u32 omap4_rev = omap_revision();
118*4882a593Smuzhiyun 
119*4882a593Smuzhiyun 	/* Same devices and geometry on both EMIFs */
120*4882a593Smuzhiyun 	if (omap4_rev == OMAP4430_ES1_0)
121*4882a593Smuzhiyun 		*regs = &emif_regs_elpida_380_mhz_1cs;
122*4882a593Smuzhiyun 	else if (omap4_rev == OMAP4430_ES2_0)
123*4882a593Smuzhiyun 		*regs = &emif_regs_elpida_200_mhz_2cs;
124*4882a593Smuzhiyun 	else if (omap4_rev < OMAP4470_ES1_0)
125*4882a593Smuzhiyun 		*regs = &emif_regs_elpida_400_mhz_2cs;
126*4882a593Smuzhiyun 	else
127*4882a593Smuzhiyun 		*regs = &emif_regs_elpida_400_mhz_1cs;
128*4882a593Smuzhiyun }
129*4882a593Smuzhiyun void emif_get_reg_dump(u32 emif_nr, const struct emif_regs **regs)
130*4882a593Smuzhiyun 	__attribute__((weak, alias("emif_get_reg_dump_sdp")));
131*4882a593Smuzhiyun 
emif_get_dmm_regs_sdp(const struct dmm_lisa_map_regs ** dmm_lisa_regs)132*4882a593Smuzhiyun static void emif_get_dmm_regs_sdp(const struct dmm_lisa_map_regs
133*4882a593Smuzhiyun 						**dmm_lisa_regs)
134*4882a593Smuzhiyun {
135*4882a593Smuzhiyun 	u32 omap_rev = omap_revision();
136*4882a593Smuzhiyun 
137*4882a593Smuzhiyun 	if (omap_rev == OMAP4430_ES1_0)
138*4882a593Smuzhiyun 		*dmm_lisa_regs = &lisa_map_2G_x_1_x_2;
139*4882a593Smuzhiyun 	else if (omap_rev < OMAP4460_ES1_0)
140*4882a593Smuzhiyun 		*dmm_lisa_regs = &lisa_map_2G_x_2_x_2;
141*4882a593Smuzhiyun 	else
142*4882a593Smuzhiyun 		*dmm_lisa_regs = &ma_lisa_map_2G_x_2_x_2;
143*4882a593Smuzhiyun }
144*4882a593Smuzhiyun 
145*4882a593Smuzhiyun void emif_get_dmm_regs(const struct dmm_lisa_map_regs **dmm_lisa_regs)
146*4882a593Smuzhiyun 	__attribute__((weak, alias("emif_get_dmm_regs_sdp")));
147*4882a593Smuzhiyun 
148*4882a593Smuzhiyun #else
149*4882a593Smuzhiyun 
150*4882a593Smuzhiyun const struct lpddr2_device_details elpida_2G_S4_details = {
151*4882a593Smuzhiyun 	.type		= LPDDR2_TYPE_S4,
152*4882a593Smuzhiyun 	.density	= LPDDR2_DENSITY_2Gb,
153*4882a593Smuzhiyun 	.io_width	= LPDDR2_IO_WIDTH_32,
154*4882a593Smuzhiyun 	.manufacturer	= LPDDR2_MANUFACTURER_ELPIDA
155*4882a593Smuzhiyun };
156*4882a593Smuzhiyun 
157*4882a593Smuzhiyun const struct lpddr2_device_details elpida_4G_S4_details = {
158*4882a593Smuzhiyun 	.type		= LPDDR2_TYPE_S4,
159*4882a593Smuzhiyun 	.density	= LPDDR2_DENSITY_4Gb,
160*4882a593Smuzhiyun 	.io_width	= LPDDR2_IO_WIDTH_32,
161*4882a593Smuzhiyun 	.manufacturer	= LPDDR2_MANUFACTURER_ELPIDA
162*4882a593Smuzhiyun };
163*4882a593Smuzhiyun 
emif_get_device_details_sdp(u32 emif_nr,u8 cs,struct lpddr2_device_details * lpddr2_dev_details)164*4882a593Smuzhiyun struct lpddr2_device_details *emif_get_device_details_sdp(u32 emif_nr, u8 cs,
165*4882a593Smuzhiyun 			struct lpddr2_device_details *lpddr2_dev_details)
166*4882a593Smuzhiyun {
167*4882a593Smuzhiyun 	u32 omap_rev = omap_revision();
168*4882a593Smuzhiyun 
169*4882a593Smuzhiyun 	/* EMIF1 & EMIF2 have identical configuration */
170*4882a593Smuzhiyun 	if (((omap_rev == OMAP4430_ES1_0) || (omap_rev == OMAP4470_ES1_0))
171*4882a593Smuzhiyun 		&& (cs == CS1)) {
172*4882a593Smuzhiyun 		/* Nothing connected on CS1 for 4430/4470 ES1.0 */
173*4882a593Smuzhiyun 		return NULL;
174*4882a593Smuzhiyun 	} else if (omap_rev < OMAP4470_ES1_0) {
175*4882a593Smuzhiyun 		/* In all other 4430/4460 cases Elpida 2G device */
176*4882a593Smuzhiyun 		*lpddr2_dev_details = elpida_2G_S4_details;
177*4882a593Smuzhiyun 	} else {
178*4882a593Smuzhiyun 		/* 4470: 4G device */
179*4882a593Smuzhiyun 		*lpddr2_dev_details = elpida_4G_S4_details;
180*4882a593Smuzhiyun 	}
181*4882a593Smuzhiyun 	return lpddr2_dev_details;
182*4882a593Smuzhiyun }
183*4882a593Smuzhiyun 
184*4882a593Smuzhiyun struct lpddr2_device_details *emif_get_device_details(u32 emif_nr, u8 cs,
185*4882a593Smuzhiyun 			struct lpddr2_device_details *lpddr2_dev_details)
186*4882a593Smuzhiyun 	__attribute__((weak, alias("emif_get_device_details_sdp")));
187*4882a593Smuzhiyun 
188*4882a593Smuzhiyun #endif /* CONFIG_SYS_EMIF_PRECALCULATED_TIMING_REGS */
189*4882a593Smuzhiyun 
190*4882a593Smuzhiyun #ifndef CONFIG_SYS_DEFAULT_LPDDR2_TIMINGS
191*4882a593Smuzhiyun static const struct lpddr2_ac_timings timings_elpida_400_mhz = {
192*4882a593Smuzhiyun 	.max_freq	= 400000000,
193*4882a593Smuzhiyun 	.RL		= 6,
194*4882a593Smuzhiyun 	.tRPab		= 21,
195*4882a593Smuzhiyun 	.tRCD		= 18,
196*4882a593Smuzhiyun 	.tWR		= 15,
197*4882a593Smuzhiyun 	.tRASmin	= 42,
198*4882a593Smuzhiyun 	.tRRD		= 10,
199*4882a593Smuzhiyun 	.tWTRx2		= 15,
200*4882a593Smuzhiyun 	.tXSR		= 140,
201*4882a593Smuzhiyun 	.tXPx2		= 15,
202*4882a593Smuzhiyun 	.tRFCab		= 130,
203*4882a593Smuzhiyun 	.tRTPx2		= 15,
204*4882a593Smuzhiyun 	.tCKE		= 3,
205*4882a593Smuzhiyun 	.tCKESR		= 15,
206*4882a593Smuzhiyun 	.tZQCS		= 90,
207*4882a593Smuzhiyun 	.tZQCL		= 360,
208*4882a593Smuzhiyun 	.tZQINIT	= 1000,
209*4882a593Smuzhiyun 	.tDQSCKMAXx2	= 11,
210*4882a593Smuzhiyun 	.tRASmax	= 70,
211*4882a593Smuzhiyun 	.tFAW		= 50
212*4882a593Smuzhiyun };
213*4882a593Smuzhiyun 
214*4882a593Smuzhiyun static const struct lpddr2_ac_timings timings_elpida_333_mhz = {
215*4882a593Smuzhiyun 	.max_freq	= 333000000,
216*4882a593Smuzhiyun 	.RL		= 5,
217*4882a593Smuzhiyun 	.tRPab		= 21,
218*4882a593Smuzhiyun 	.tRCD		= 18,
219*4882a593Smuzhiyun 	.tWR		= 15,
220*4882a593Smuzhiyun 	.tRASmin	= 42,
221*4882a593Smuzhiyun 	.tRRD		= 10,
222*4882a593Smuzhiyun 	.tWTRx2		= 15,
223*4882a593Smuzhiyun 	.tXSR		= 140,
224*4882a593Smuzhiyun 	.tXPx2		= 15,
225*4882a593Smuzhiyun 	.tRFCab		= 130,
226*4882a593Smuzhiyun 	.tRTPx2		= 15,
227*4882a593Smuzhiyun 	.tCKE		= 3,
228*4882a593Smuzhiyun 	.tCKESR		= 15,
229*4882a593Smuzhiyun 	.tZQCS		= 90,
230*4882a593Smuzhiyun 	.tZQCL		= 360,
231*4882a593Smuzhiyun 	.tZQINIT	= 1000,
232*4882a593Smuzhiyun 	.tDQSCKMAXx2	= 11,
233*4882a593Smuzhiyun 	.tRASmax	= 70,
234*4882a593Smuzhiyun 	.tFAW		= 50
235*4882a593Smuzhiyun };
236*4882a593Smuzhiyun 
237*4882a593Smuzhiyun static const struct lpddr2_ac_timings timings_elpida_200_mhz = {
238*4882a593Smuzhiyun 	.max_freq	= 200000000,
239*4882a593Smuzhiyun 	.RL		= 3,
240*4882a593Smuzhiyun 	.tRPab		= 21,
241*4882a593Smuzhiyun 	.tRCD		= 18,
242*4882a593Smuzhiyun 	.tWR		= 15,
243*4882a593Smuzhiyun 	.tRASmin	= 42,
244*4882a593Smuzhiyun 	.tRRD		= 10,
245*4882a593Smuzhiyun 	.tWTRx2		= 20,
246*4882a593Smuzhiyun 	.tXSR		= 140,
247*4882a593Smuzhiyun 	.tXPx2		= 15,
248*4882a593Smuzhiyun 	.tRFCab		= 130,
249*4882a593Smuzhiyun 	.tRTPx2		= 15,
250*4882a593Smuzhiyun 	.tCKE		= 3,
251*4882a593Smuzhiyun 	.tCKESR		= 15,
252*4882a593Smuzhiyun 	.tZQCS		= 90,
253*4882a593Smuzhiyun 	.tZQCL		= 360,
254*4882a593Smuzhiyun 	.tZQINIT	= 1000,
255*4882a593Smuzhiyun 	.tDQSCKMAXx2	= 11,
256*4882a593Smuzhiyun 	.tRASmax	= 70,
257*4882a593Smuzhiyun 	.tFAW		= 50
258*4882a593Smuzhiyun };
259*4882a593Smuzhiyun 
260*4882a593Smuzhiyun static const struct lpddr2_min_tck min_tck_elpida = {
261*4882a593Smuzhiyun 	.tRL		= 3,
262*4882a593Smuzhiyun 	.tRP_AB		= 3,
263*4882a593Smuzhiyun 	.tRCD		= 3,
264*4882a593Smuzhiyun 	.tWR		= 3,
265*4882a593Smuzhiyun 	.tRAS_MIN	= 3,
266*4882a593Smuzhiyun 	.tRRD		= 2,
267*4882a593Smuzhiyun 	.tWTR		= 2,
268*4882a593Smuzhiyun 	.tXP		= 2,
269*4882a593Smuzhiyun 	.tRTP		= 2,
270*4882a593Smuzhiyun 	.tCKE		= 3,
271*4882a593Smuzhiyun 	.tCKESR		= 3,
272*4882a593Smuzhiyun 	.tFAW		= 8
273*4882a593Smuzhiyun };
274*4882a593Smuzhiyun 
275*4882a593Smuzhiyun static const struct lpddr2_ac_timings *elpida_ac_timings[MAX_NUM_SPEEDBINS] = {
276*4882a593Smuzhiyun 		&timings_elpida_200_mhz,
277*4882a593Smuzhiyun 		&timings_elpida_333_mhz,
278*4882a593Smuzhiyun 		&timings_elpida_400_mhz
279*4882a593Smuzhiyun };
280*4882a593Smuzhiyun 
281*4882a593Smuzhiyun const struct lpddr2_device_timings elpida_2G_S4_timings = {
282*4882a593Smuzhiyun 	.ac_timings	= elpida_ac_timings,
283*4882a593Smuzhiyun 	.min_tck	= &min_tck_elpida,
284*4882a593Smuzhiyun };
285*4882a593Smuzhiyun 
emif_get_device_timings_sdp(u32 emif_nr,const struct lpddr2_device_timings ** cs0_device_timings,const struct lpddr2_device_timings ** cs1_device_timings)286*4882a593Smuzhiyun void emif_get_device_timings_sdp(u32 emif_nr,
287*4882a593Smuzhiyun 		const struct lpddr2_device_timings **cs0_device_timings,
288*4882a593Smuzhiyun 		const struct lpddr2_device_timings **cs1_device_timings)
289*4882a593Smuzhiyun {
290*4882a593Smuzhiyun 	u32 omap_rev = omap_revision();
291*4882a593Smuzhiyun 
292*4882a593Smuzhiyun 	/* Identical devices on EMIF1 & EMIF2 */
293*4882a593Smuzhiyun 	*cs0_device_timings = &elpida_2G_S4_timings;
294*4882a593Smuzhiyun 
295*4882a593Smuzhiyun 	if ((omap_rev == OMAP4430_ES1_0) || (omap_rev == OMAP4470_ES1_0))
296*4882a593Smuzhiyun 		*cs1_device_timings = NULL;
297*4882a593Smuzhiyun 	else
298*4882a593Smuzhiyun 		*cs1_device_timings = &elpida_2G_S4_timings;
299*4882a593Smuzhiyun }
300*4882a593Smuzhiyun 
301*4882a593Smuzhiyun void emif_get_device_timings(u32 emif_nr,
302*4882a593Smuzhiyun 		const struct lpddr2_device_timings **cs0_device_timings,
303*4882a593Smuzhiyun 		const struct lpddr2_device_timings **cs1_device_timings)
304*4882a593Smuzhiyun 	__attribute__((weak, alias("emif_get_device_timings_sdp")));
305*4882a593Smuzhiyun 
306*4882a593Smuzhiyun #endif /* CONFIG_SYS_DEFAULT_LPDDR2_TIMINGS */
307*4882a593Smuzhiyun 
308*4882a593Smuzhiyun const struct lpddr2_mr_regs mr_regs = {
309*4882a593Smuzhiyun 	.mr1	= MR1_BL_8_BT_SEQ_WRAP_EN_NWR_3,
310*4882a593Smuzhiyun 	.mr2	= 0x4,
311*4882a593Smuzhiyun 	.mr3	= -1,
312*4882a593Smuzhiyun 	.mr10	= MR10_ZQ_ZQINIT,
313*4882a593Smuzhiyun 	.mr16	= MR16_REF_FULL_ARRAY
314*4882a593Smuzhiyun };
315*4882a593Smuzhiyun 
get_lpddr2_mr_regs(const struct lpddr2_mr_regs ** regs)316*4882a593Smuzhiyun void get_lpddr2_mr_regs(const struct lpddr2_mr_regs **regs)
317*4882a593Smuzhiyun {
318*4882a593Smuzhiyun 	*regs = &mr_regs;
319*4882a593Smuzhiyun }
320*4882a593Smuzhiyun 
get_bug_regs(u32 * iterations)321*4882a593Smuzhiyun __weak const struct read_write_regs *get_bug_regs(u32 *iterations)
322*4882a593Smuzhiyun {
323*4882a593Smuzhiyun 	return 0;
324*4882a593Smuzhiyun }
325