linux_dsm_epyc7002/drivers/gpu/drm/nouveau/dispnv04/dac.c
Ben Skeggs 1a64634255 drm/nv04/disp: hide all the cruft away in its own little hole
It'd be pretty awesome if someone would care enough to port this all
properly to a class interface, perhaps submitting a command stream to
the core via a sw object on PFIFO (emulating how EVO works basically,
and also what nvidia have done forever..)..

But, this seems unlikely given how old this hardware is now, so, lets
just hide it away.

There's a heap of other bits and pieces laying around that are still
tangled.  I'll (re)move them in pieces.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2013-04-26 15:37:51 +10:00

557 lines
18 KiB
C

/*
* Copyright 2003 NVIDIA, Corporation
* Copyright 2006 Dave Airlie
* Copyright 2007 Maarten Maathuis
* Copyright 2007-2009 Stuart Bennett
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
#include <drm/drmP.h>
#include <drm/drm_crtc_helper.h>
#include "nouveau_drm.h"
#include "nouveau_encoder.h"
#include "nouveau_connector.h"
#include "nouveau_crtc.h"
#include "hw.h"
#include "nvreg.h"
#include <subdev/bios/gpio.h>
#include <subdev/gpio.h>
#include <subdev/timer.h>
int nv04_dac_output_offset(struct drm_encoder *encoder)
{
struct dcb_output *dcb = nouveau_encoder(encoder)->dcb;
int offset = 0;
if (dcb->or & (8 | DCB_OUTPUT_C))
offset += 0x68;
if (dcb->or & (8 | DCB_OUTPUT_B))
offset += 0x2000;
return offset;
}
/*
* arbitrary limit to number of sense oscillations tolerated in one sample
* period (observed to be at least 13 in "nvidia")
*/
#define MAX_HBLANK_OSC 20
/*
* arbitrary limit to number of conflicting sample pairs to tolerate at a
* voltage step (observed to be at least 5 in "nvidia")
*/
#define MAX_SAMPLE_PAIRS 10
static int sample_load_twice(struct drm_device *dev, bool sense[2])
{
struct nouveau_device *device = nouveau_dev(dev);
struct nouveau_timer *ptimer = nouveau_timer(device);
int i;
for (i = 0; i < 2; i++) {
bool sense_a, sense_b, sense_b_prime;
int j = 0;
/*
* wait for bit 0 clear -- out of hblank -- (say reg value 0x4),
* then wait for transition 0x4->0x5->0x4: enter hblank, leave
* hblank again
* use a 10ms timeout (guards against crtc being inactive, in
* which case blank state would never change)
*/
if (!nouveau_timer_wait_eq(ptimer, 10000000,
NV_PRMCIO_INP0__COLOR,
0x00000001, 0x00000000))
return -EBUSY;
if (!nouveau_timer_wait_eq(ptimer, 10000000,
NV_PRMCIO_INP0__COLOR,
0x00000001, 0x00000001))
return -EBUSY;
if (!nouveau_timer_wait_eq(ptimer, 10000000,
NV_PRMCIO_INP0__COLOR,
0x00000001, 0x00000000))
return -EBUSY;
udelay(100);
/* when level triggers, sense is _LO_ */
sense_a = nv_rd08(device, NV_PRMCIO_INP0) & 0x10;
/* take another reading until it agrees with sense_a... */
do {
udelay(100);
sense_b = nv_rd08(device, NV_PRMCIO_INP0) & 0x10;
if (sense_a != sense_b) {
sense_b_prime =
nv_rd08(device, NV_PRMCIO_INP0) & 0x10;
if (sense_b == sense_b_prime) {
/* ... unless two consecutive subsequent
* samples agree; sense_a is replaced */
sense_a = sense_b;
/* force mis-match so we loop */
sense_b = !sense_a;
}
}
} while ((sense_a != sense_b) && ++j < MAX_HBLANK_OSC);
if (j == MAX_HBLANK_OSC)
/* with so much oscillation, default to sense:LO */
sense[i] = false;
else
sense[i] = sense_a;
}
return 0;
}
static enum drm_connector_status nv04_dac_detect(struct drm_encoder *encoder,
struct drm_connector *connector)
{
struct drm_device *dev = encoder->dev;
struct nouveau_device *device = nouveau_dev(dev);
struct nouveau_drm *drm = nouveau_drm(dev);
uint8_t saved_seq1, saved_pi, saved_rpc1, saved_cr_mode;
uint8_t saved_palette0[3], saved_palette_mask;
uint32_t saved_rtest_ctrl, saved_rgen_ctrl;
int i;
uint8_t blue;
bool sense = true;
/*
* for this detection to work, there needs to be a mode set up on the
* CRTC. this is presumed to be the case
*/
if (nv_two_heads(dev))
/* only implemented for head A for now */
NVSetOwner(dev, 0);
saved_cr_mode = NVReadVgaCrtc(dev, 0, NV_CIO_CR_MODE_INDEX);
NVWriteVgaCrtc(dev, 0, NV_CIO_CR_MODE_INDEX, saved_cr_mode | 0x80);
saved_seq1 = NVReadVgaSeq(dev, 0, NV_VIO_SR_CLOCK_INDEX);
NVWriteVgaSeq(dev, 0, NV_VIO_SR_CLOCK_INDEX, saved_seq1 & ~0x20);
saved_rtest_ctrl = NVReadRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL);
NVWriteRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL,
saved_rtest_ctrl & ~NV_PRAMDAC_TEST_CONTROL_PWRDWN_DAC_OFF);
msleep(10);
saved_pi = NVReadVgaCrtc(dev, 0, NV_CIO_CRE_PIXEL_INDEX);
NVWriteVgaCrtc(dev, 0, NV_CIO_CRE_PIXEL_INDEX,
saved_pi & ~(0x80 | MASK(NV_CIO_CRE_PIXEL_FORMAT)));
saved_rpc1 = NVReadVgaCrtc(dev, 0, NV_CIO_CRE_RPC1_INDEX);
NVWriteVgaCrtc(dev, 0, NV_CIO_CRE_RPC1_INDEX, saved_rpc1 & ~0xc0);
nv_wr08(device, NV_PRMDIO_READ_MODE_ADDRESS, 0x0);
for (i = 0; i < 3; i++)
saved_palette0[i] = nv_rd08(device, NV_PRMDIO_PALETTE_DATA);
saved_palette_mask = nv_rd08(device, NV_PRMDIO_PIXEL_MASK);
nv_wr08(device, NV_PRMDIO_PIXEL_MASK, 0);
saved_rgen_ctrl = NVReadRAMDAC(dev, 0, NV_PRAMDAC_GENERAL_CONTROL);
NVWriteRAMDAC(dev, 0, NV_PRAMDAC_GENERAL_CONTROL,
(saved_rgen_ctrl & ~(NV_PRAMDAC_GENERAL_CONTROL_BPC_8BITS |
NV_PRAMDAC_GENERAL_CONTROL_TERMINATION_75OHM)) |
NV_PRAMDAC_GENERAL_CONTROL_PIXMIX_ON);
blue = 8; /* start of test range */
do {
bool sense_pair[2];
nv_wr08(device, NV_PRMDIO_WRITE_MODE_ADDRESS, 0);
nv_wr08(device, NV_PRMDIO_PALETTE_DATA, 0);
nv_wr08(device, NV_PRMDIO_PALETTE_DATA, 0);
/* testing blue won't find monochrome monitors. I don't care */
nv_wr08(device, NV_PRMDIO_PALETTE_DATA, blue);
i = 0;
/* take sample pairs until both samples in the pair agree */
do {
if (sample_load_twice(dev, sense_pair))
goto out;
} while ((sense_pair[0] != sense_pair[1]) &&
++i < MAX_SAMPLE_PAIRS);
if (i == MAX_SAMPLE_PAIRS)
/* too much oscillation defaults to LO */
sense = false;
else
sense = sense_pair[0];
/*
* if sense goes LO before blue ramps to 0x18, monitor is not connected.
* ergo, if blue gets to 0x18, monitor must be connected
*/
} while (++blue < 0x18 && sense);
out:
nv_wr08(device, NV_PRMDIO_PIXEL_MASK, saved_palette_mask);
NVWriteRAMDAC(dev, 0, NV_PRAMDAC_GENERAL_CONTROL, saved_rgen_ctrl);
nv_wr08(device, NV_PRMDIO_WRITE_MODE_ADDRESS, 0);
for (i = 0; i < 3; i++)
nv_wr08(device, NV_PRMDIO_PALETTE_DATA, saved_palette0[i]);
NVWriteRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL, saved_rtest_ctrl);
NVWriteVgaCrtc(dev, 0, NV_CIO_CRE_PIXEL_INDEX, saved_pi);
NVWriteVgaCrtc(dev, 0, NV_CIO_CRE_RPC1_INDEX, saved_rpc1);
NVWriteVgaSeq(dev, 0, NV_VIO_SR_CLOCK_INDEX, saved_seq1);
NVWriteVgaCrtc(dev, 0, NV_CIO_CR_MODE_INDEX, saved_cr_mode);
if (blue == 0x18) {
NV_DEBUG(drm, "Load detected on head A\n");
return connector_status_connected;
}
return connector_status_disconnected;
}
uint32_t nv17_dac_sample_load(struct drm_encoder *encoder)
{
struct drm_device *dev = encoder->dev;
struct nouveau_drm *drm = nouveau_drm(dev);
struct nouveau_device *device = nouveau_dev(dev);
struct nouveau_gpio *gpio = nouveau_gpio(device);
struct dcb_output *dcb = nouveau_encoder(encoder)->dcb;
uint32_t sample, testval, regoffset = nv04_dac_output_offset(encoder);
uint32_t saved_powerctrl_2 = 0, saved_powerctrl_4 = 0, saved_routput,
saved_rtest_ctrl, saved_gpio0 = 0, saved_gpio1 = 0, temp, routput;
int head;
#define RGB_TEST_DATA(r, g, b) (r << 0 | g << 10 | b << 20)
if (dcb->type == DCB_OUTPUT_TV) {
testval = RGB_TEST_DATA(0xa0, 0xa0, 0xa0);
if (drm->vbios.tvdactestval)
testval = drm->vbios.tvdactestval;
} else {
testval = RGB_TEST_DATA(0x140, 0x140, 0x140); /* 0x94050140 */
if (drm->vbios.dactestval)
testval = drm->vbios.dactestval;
}
saved_rtest_ctrl = NVReadRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL + regoffset);
NVWriteRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL + regoffset,
saved_rtest_ctrl & ~NV_PRAMDAC_TEST_CONTROL_PWRDWN_DAC_OFF);
saved_powerctrl_2 = nv_rd32(device, NV_PBUS_POWERCTRL_2);
nv_wr32(device, NV_PBUS_POWERCTRL_2, saved_powerctrl_2 & 0xd7ffffff);
if (regoffset == 0x68) {
saved_powerctrl_4 = nv_rd32(device, NV_PBUS_POWERCTRL_4);
nv_wr32(device, NV_PBUS_POWERCTRL_4, saved_powerctrl_4 & 0xffffffcf);
}
if (gpio) {
saved_gpio1 = gpio->get(gpio, 0, DCB_GPIO_TVDAC1, 0xff);
saved_gpio0 = gpio->get(gpio, 0, DCB_GPIO_TVDAC0, 0xff);
gpio->set(gpio, 0, DCB_GPIO_TVDAC1, 0xff, dcb->type == DCB_OUTPUT_TV);
gpio->set(gpio, 0, DCB_GPIO_TVDAC0, 0xff, dcb->type == DCB_OUTPUT_TV);
}
msleep(4);
saved_routput = NVReadRAMDAC(dev, 0, NV_PRAMDAC_DACCLK + regoffset);
head = (saved_routput & 0x100) >> 8;
/* if there's a spare crtc, using it will minimise flicker */
if (!(NVReadVgaCrtc(dev, head, NV_CIO_CRE_RPC1_INDEX) & 0xC0))
head ^= 1;
/* nv driver and nv31 use 0xfffffeee, nv34 and 6600 use 0xfffffece */
routput = (saved_routput & 0xfffffece) | head << 8;
if (nv_device(drm->device)->card_type >= NV_40) {
if (dcb->type == DCB_OUTPUT_TV)
routput |= 0x1a << 16;
else
routput &= ~(0x1a << 16);
}
NVWriteRAMDAC(dev, 0, NV_PRAMDAC_DACCLK + regoffset, routput);
msleep(1);
temp = NVReadRAMDAC(dev, 0, NV_PRAMDAC_DACCLK + regoffset);
NVWriteRAMDAC(dev, 0, NV_PRAMDAC_DACCLK + regoffset, temp | 1);
NVWriteRAMDAC(dev, head, NV_PRAMDAC_TESTPOINT_DATA,
NV_PRAMDAC_TESTPOINT_DATA_NOTBLANK | testval);
temp = NVReadRAMDAC(dev, head, NV_PRAMDAC_TEST_CONTROL);
NVWriteRAMDAC(dev, head, NV_PRAMDAC_TEST_CONTROL,
temp | NV_PRAMDAC_TEST_CONTROL_TP_INS_EN_ASSERTED);
msleep(5);
sample = NVReadRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL + regoffset);
/* do it again just in case it's a residual current */
sample &= NVReadRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL + regoffset);
temp = NVReadRAMDAC(dev, head, NV_PRAMDAC_TEST_CONTROL);
NVWriteRAMDAC(dev, head, NV_PRAMDAC_TEST_CONTROL,
temp & ~NV_PRAMDAC_TEST_CONTROL_TP_INS_EN_ASSERTED);
NVWriteRAMDAC(dev, head, NV_PRAMDAC_TESTPOINT_DATA, 0);
/* bios does something more complex for restoring, but I think this is good enough */
NVWriteRAMDAC(dev, 0, NV_PRAMDAC_DACCLK + regoffset, saved_routput);
NVWriteRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL + regoffset, saved_rtest_ctrl);
if (regoffset == 0x68)
nv_wr32(device, NV_PBUS_POWERCTRL_4, saved_powerctrl_4);
nv_wr32(device, NV_PBUS_POWERCTRL_2, saved_powerctrl_2);
if (gpio) {
gpio->set(gpio, 0, DCB_GPIO_TVDAC1, 0xff, saved_gpio1);
gpio->set(gpio, 0, DCB_GPIO_TVDAC0, 0xff, saved_gpio0);
}
return sample;
}
static enum drm_connector_status
nv17_dac_detect(struct drm_encoder *encoder, struct drm_connector *connector)
{
struct nouveau_drm *drm = nouveau_drm(encoder->dev);
struct dcb_output *dcb = nouveau_encoder(encoder)->dcb;
if (nv04_dac_in_use(encoder))
return connector_status_disconnected;
if (nv17_dac_sample_load(encoder) &
NV_PRAMDAC_TEST_CONTROL_SENSEB_ALLHI) {
NV_DEBUG(drm, "Load detected on output %c\n",
'@' + ffs(dcb->or));
return connector_status_connected;
} else {
return connector_status_disconnected;
}
}
static bool nv04_dac_mode_fixup(struct drm_encoder *encoder,
const struct drm_display_mode *mode,
struct drm_display_mode *adjusted_mode)
{
if (nv04_dac_in_use(encoder))
return false;
return true;
}
static void nv04_dac_prepare(struct drm_encoder *encoder)
{
struct drm_encoder_helper_funcs *helper = encoder->helper_private;
struct drm_device *dev = encoder->dev;
int head = nouveau_crtc(encoder->crtc)->index;
helper->dpms(encoder, DRM_MODE_DPMS_OFF);
nv04_dfp_disable(dev, head);
}
static void nv04_dac_mode_set(struct drm_encoder *encoder,
struct drm_display_mode *mode,
struct drm_display_mode *adjusted_mode)
{
struct drm_device *dev = encoder->dev;
struct nouveau_drm *drm = nouveau_drm(dev);
int head = nouveau_crtc(encoder->crtc)->index;
if (nv_gf4_disp_arch(dev)) {
struct drm_encoder *rebind;
uint32_t dac_offset = nv04_dac_output_offset(encoder);
uint32_t otherdac;
/* bit 16-19 are bits that are set on some G70 cards,
* but don't seem to have much effect */
NVWriteRAMDAC(dev, 0, NV_PRAMDAC_DACCLK + dac_offset,
head << 8 | NV_PRAMDAC_DACCLK_SEL_DACCLK);
/* force any other vga encoders to bind to the other crtc */
list_for_each_entry(rebind, &dev->mode_config.encoder_list, head) {
if (rebind == encoder
|| nouveau_encoder(rebind)->dcb->type != DCB_OUTPUT_ANALOG)
continue;
dac_offset = nv04_dac_output_offset(rebind);
otherdac = NVReadRAMDAC(dev, 0, NV_PRAMDAC_DACCLK + dac_offset);
NVWriteRAMDAC(dev, 0, NV_PRAMDAC_DACCLK + dac_offset,
(otherdac & ~0x0100) | (head ^ 1) << 8);
}
}
/* This could use refinement for flatpanels, but it should work this way */
if (nv_device(drm->device)->chipset < 0x44)
NVWriteRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL + nv04_dac_output_offset(encoder), 0xf0000000);
else
NVWriteRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL + nv04_dac_output_offset(encoder), 0x00100000);
}
static void nv04_dac_commit(struct drm_encoder *encoder)
{
struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
struct nouveau_drm *drm = nouveau_drm(encoder->dev);
struct nouveau_crtc *nv_crtc = nouveau_crtc(encoder->crtc);
struct drm_encoder_helper_funcs *helper = encoder->helper_private;
helper->dpms(encoder, DRM_MODE_DPMS_ON);
NV_DEBUG(drm, "Output %s is running on CRTC %d using output %c\n",
drm_get_connector_name(&nouveau_encoder_connector_get(nv_encoder)->base),
nv_crtc->index, '@' + ffs(nv_encoder->dcb->or));
}
void nv04_dac_update_dacclk(struct drm_encoder *encoder, bool enable)
{
struct drm_device *dev = encoder->dev;
struct dcb_output *dcb = nouveau_encoder(encoder)->dcb;
if (nv_gf4_disp_arch(dev)) {
uint32_t *dac_users = &nv04_display(dev)->dac_users[ffs(dcb->or) - 1];
int dacclk_off = NV_PRAMDAC_DACCLK + nv04_dac_output_offset(encoder);
uint32_t dacclk = NVReadRAMDAC(dev, 0, dacclk_off);
if (enable) {
*dac_users |= 1 << dcb->index;
NVWriteRAMDAC(dev, 0, dacclk_off, dacclk | NV_PRAMDAC_DACCLK_SEL_DACCLK);
} else {
*dac_users &= ~(1 << dcb->index);
if (!*dac_users)
NVWriteRAMDAC(dev, 0, dacclk_off,
dacclk & ~NV_PRAMDAC_DACCLK_SEL_DACCLK);
}
}
}
/* Check if the DAC corresponding to 'encoder' is being used by
* someone else. */
bool nv04_dac_in_use(struct drm_encoder *encoder)
{
struct drm_device *dev = encoder->dev;
struct dcb_output *dcb = nouveau_encoder(encoder)->dcb;
return nv_gf4_disp_arch(encoder->dev) &&
(nv04_display(dev)->dac_users[ffs(dcb->or) - 1] & ~(1 << dcb->index));
}
static void nv04_dac_dpms(struct drm_encoder *encoder, int mode)
{
struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
struct nouveau_drm *drm = nouveau_drm(encoder->dev);
if (nv_encoder->last_dpms == mode)
return;
nv_encoder->last_dpms = mode;
NV_DEBUG(drm, "Setting dpms mode %d on vga encoder (output %d)\n",
mode, nv_encoder->dcb->index);
nv04_dac_update_dacclk(encoder, mode == DRM_MODE_DPMS_ON);
}
static void nv04_dac_save(struct drm_encoder *encoder)
{
struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
struct drm_device *dev = encoder->dev;
if (nv_gf4_disp_arch(dev))
nv_encoder->restore.output = NVReadRAMDAC(dev, 0, NV_PRAMDAC_DACCLK +
nv04_dac_output_offset(encoder));
}
static void nv04_dac_restore(struct drm_encoder *encoder)
{
struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
struct drm_device *dev = encoder->dev;
if (nv_gf4_disp_arch(dev))
NVWriteRAMDAC(dev, 0, NV_PRAMDAC_DACCLK + nv04_dac_output_offset(encoder),
nv_encoder->restore.output);
nv_encoder->last_dpms = NV_DPMS_CLEARED;
}
static void nv04_dac_destroy(struct drm_encoder *encoder)
{
struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
drm_encoder_cleanup(encoder);
kfree(nv_encoder);
}
static const struct drm_encoder_helper_funcs nv04_dac_helper_funcs = {
.dpms = nv04_dac_dpms,
.save = nv04_dac_save,
.restore = nv04_dac_restore,
.mode_fixup = nv04_dac_mode_fixup,
.prepare = nv04_dac_prepare,
.commit = nv04_dac_commit,
.mode_set = nv04_dac_mode_set,
.detect = nv04_dac_detect
};
static const struct drm_encoder_helper_funcs nv17_dac_helper_funcs = {
.dpms = nv04_dac_dpms,
.save = nv04_dac_save,
.restore = nv04_dac_restore,
.mode_fixup = nv04_dac_mode_fixup,
.prepare = nv04_dac_prepare,
.commit = nv04_dac_commit,
.mode_set = nv04_dac_mode_set,
.detect = nv17_dac_detect
};
static const struct drm_encoder_funcs nv04_dac_funcs = {
.destroy = nv04_dac_destroy,
};
int
nv04_dac_create(struct drm_connector *connector, struct dcb_output *entry)
{
const struct drm_encoder_helper_funcs *helper;
struct nouveau_encoder *nv_encoder = NULL;
struct drm_device *dev = connector->dev;
struct drm_encoder *encoder;
nv_encoder = kzalloc(sizeof(*nv_encoder), GFP_KERNEL);
if (!nv_encoder)
return -ENOMEM;
encoder = to_drm_encoder(nv_encoder);
nv_encoder->dcb = entry;
nv_encoder->or = ffs(entry->or) - 1;
if (nv_gf4_disp_arch(dev))
helper = &nv17_dac_helper_funcs;
else
helper = &nv04_dac_helper_funcs;
drm_encoder_init(dev, encoder, &nv04_dac_funcs, DRM_MODE_ENCODER_DAC);
drm_encoder_helper_add(encoder, helper);
encoder->possible_crtcs = entry->heads;
encoder->possible_clones = 0;
drm_mode_connector_attach_encoder(connector, encoder);
return 0;
}