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u-boot/arch/arm/cpu/armv7/sunxi/dram_sun8i.c
Siarhei Siamashka c3d2b963c6 sunxi: Fix buggy sun6i/sun8i DRAM size detection logic 
After reboot, reset or even short power off, DRAM typically retains
the old stale data for some period of time (for this type of memory,
the bits of data are stored in slowly discharging capacitors).

The current sun6i/sun8i DRAM size detection logic, which is
inherited from the Allwinner code, relies on using a large magic
signature with the hope that it is unique enough and unlikely to
ever accidentally match this leftover garbage data in RAM. But
this approach is inherently unsafe, as can be demonstrated using
the following test program:

/***** A testcase for reproducing the problem ******/

void main(int argc, char *argv[])
{
    size_t size, i;
    uint32_t *buf;
    /* Allocate the buffer */
    if (argc < 2 || !(size = (size_t)atoi(argv[1]) * 1048576) ||
                    !(buf = malloc(size))) {
        printf("Need buffer size in MiB as a cmdline argument\n");
        exit(1);
    }
    /* Fill it with the Allwinner DRAM "magic" values */
    for (i = 0; i < size / 4; i++)
        buf[i] = 0xaa55aa55 + ((uintptr_t)&buf[i] / 4) % 64;
    /* Try to reboot */
    system("reboot");
    /* And wait */
    for (;;) {}
}
/***************************************************/

If this test program is run on the device (giving it a large
chunk of memory), then the DRAM size detection logic in u-boot
gets confused after reboot and fails to initialize DRAM properly.

A better approach is not to rely on luck and abstain from making
any assumptions about the properties of the leftover garbage
data in RAM. Instead just use a more reliable code for testing
whether two different addresses refer to the same memory location.

Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
2015-01-14 14:56:37 +01:00

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/*
* Sun8i platform dram controller init.
*
* (C) Copyright 2014 Hans de Goede <hdegoede@redhat.com>
*
* SPDX-License-Identifier: GPL-2.0+
*/
/*
* Note this code uses a lot of magic hex values, that is because this code
* simply replays the init sequence as done by the Allwinner boot0 code, so
* we do not know what these values mean. There are no symbolic constants for
* these magic values, since we do not know how to name them and making up
* names for them is not useful.
*
* The register-layout of the sunxi_mctl_phy_reg-s looks a lot like the one
* found in the TI Keystone2 documentation:
* http://www.ti.com/lit/ug/spruhn7a/spruhn7a.pdf
* "Table4-2 DDR3 PHY Registers"
* This may be used as a (possible) reference for future work / cleanups.
*/
#include <common.h>
#include <errno.h>
#include <asm/io.h>
#include <asm/arch/clock.h>
#include <asm/arch/dram.h>
#include <asm/arch/prcm.h>
static const struct dram_para dram_para = {
.clock = CONFIG_DRAM_CLK,
.type = 3,
.zq = CONFIG_DRAM_ZQ,
.odt_en = 1,
.para1 = 0, /* not used (only used when tpr13 bit 31 is set */
.para2 = 0, /* not used (only used when tpr13 bit 31 is set */
.mr0 = 6736,
.mr1 = 4,
.mr2 = 16,
.mr3 = 0,
/* tpr0 - 10 contain timing constants or-ed together in u32 vals */
.tpr0 = 0x2ab83def,
.tpr1 = 0x18082356,
.tpr2 = 0x00034156,
.tpr3 = 0x448c5533,
.tpr4 = 0x08010d00,
.tpr5 = 0x0340b20f,
.tpr6 = 0x20d118cc,
.tpr7 = 0x14062485,
.tpr8 = 0x220d1d52,
.tpr9 = 0x1e078c22,
.tpr10 = 0x3c,
.tpr11 = 0, /* not used */
.tpr12 = 0, /* not used */
.tpr13 = 0x30000,
};
static void mctl_sys_init(void)
{
struct sunxi_ccm_reg * const ccm =
(struct sunxi_ccm_reg *)SUNXI_CCM_BASE;
/* enable pll5, note the divide by 2 is deliberate! */
clock_set_pll5(dram_para.clock * 1000000 / 2,
dram_para.tpr13 & 0x40000);
/* deassert ahb mctl reset */
setbits_le32(&ccm->ahb_reset0_cfg, 1 << AHB_RESET_OFFSET_MCTL);
/* enable ahb mctl clock */
setbits_le32(&ccm->ahb_gate0, 1 << AHB_GATE_OFFSET_MCTL);
}
static void mctl_apply_odt_correction(u32 *reg, int correction)
{
int val;
val = (readl(reg) >> 8) & 0xff;
val += correction;
/* clamp */
if (val < 0)
val = 0;
else if (val > 255)
val = 255;
clrsetbits_le32(reg, 0xff00, val << 8);
}
static void mctl_init(u32 *bus_width)
{
struct sunxi_ccm_reg * const ccm =
(struct sunxi_ccm_reg *)SUNXI_CCM_BASE;
struct sunxi_mctl_com_reg * const mctl_com =
(struct sunxi_mctl_com_reg *)SUNXI_DRAM_COM_BASE;
struct sunxi_mctl_ctl_reg * const mctl_ctl =
(struct sunxi_mctl_ctl_reg *)SUNXI_DRAM_CTL0_BASE;
struct sunxi_mctl_phy_reg * const mctl_phy =
(struct sunxi_mctl_phy_reg *)SUNXI_DRAM_PHY0_BASE;
int correction;
if (dram_para.tpr13 & 0x20)
writel(0x40b, &mctl_phy->dcr);
else
writel(0x1000040b, &mctl_phy->dcr);
if (dram_para.clock >= 480)
writel(0x5c000, &mctl_phy->dllgcr);
else
writel(0xdc000, &mctl_phy->dllgcr);
writel(0x0a003e3f, &mctl_phy->pgcr0);
writel(0x03008421, &mctl_phy->pgcr1);
writel(dram_para.mr0, &mctl_phy->mr0);
writel(dram_para.mr1, &mctl_phy->mr1);
writel(dram_para.mr2, &mctl_phy->mr2);
writel(dram_para.mr3, &mctl_phy->mr3);
if (!(dram_para.tpr13 & 0x10000)) {
clrsetbits_le32(&mctl_phy->dx0gcr, 0x3800, 0x2000);
clrsetbits_le32(&mctl_phy->dx1gcr, 0x3800, 0x2000);
}
/*
* All the masking and shifting below converts what I assume are DDR
* timing constants from Allwinner dram_para tpr format to the actual
* timing registers format.
*/
writel((dram_para.tpr0 & 0x000fffff), &mctl_phy->ptr2);
writel((dram_para.tpr1 & 0x1fffffff), &mctl_phy->ptr3);
writel((dram_para.tpr0 & 0x3ff00000) >> 2 |
(dram_para.tpr2 & 0x0003ffff), &mctl_phy->ptr4);
writel(dram_para.tpr3, &mctl_phy->dtpr0);
writel(dram_para.tpr4, &mctl_phy->dtpr2);
writel(0x01000081, &mctl_phy->dtcr);
if (dram_para.clock <= 240 || !(dram_para.odt_en & 0x01)) {
clrbits_le32(&mctl_phy->dx0gcr, 0x600);
clrbits_le32(&mctl_phy->dx1gcr, 0x600);
}
if (dram_para.clock <= 240) {
writel(0, &mctl_phy->odtcr);
writel(0, &mctl_ctl->odtmap);
}
writel(((dram_para.tpr5 & 0x0f00) << 12) |
((dram_para.tpr5 & 0x00f8) << 9) |
((dram_para.tpr5 & 0x0007) << 8),
&mctl_ctl->rfshctl0);
writel(((dram_para.tpr5 & 0x0003f000) << 12) |
((dram_para.tpr5 & 0x00fc0000) >> 2) |
((dram_para.tpr5 & 0x3f000000) >> 16) |
((dram_para.tpr6 & 0x0000003f) >> 0),
&mctl_ctl->dramtmg0);
writel(((dram_para.tpr6 & 0x000007c0) << 10) |
((dram_para.tpr6 & 0x0000f800) >> 3) |
((dram_para.tpr6 & 0x003f0000) >> 16),
&mctl_ctl->dramtmg1);
writel(((dram_para.tpr6 & 0x0fc00000) << 2) |
((dram_para.tpr7 & 0x0000001f) << 16) |
((dram_para.tpr7 & 0x000003e0) << 3) |
((dram_para.tpr7 & 0x0000fc00) >> 10),
&mctl_ctl->dramtmg2);
writel(((dram_para.tpr7 & 0x03ff0000) >> 16) |
((dram_para.tpr6 & 0xf0000000) >> 16),
&mctl_ctl->dramtmg3);
writel(((dram_para.tpr7 & 0x3c000000) >> 2 ) |
((dram_para.tpr8 & 0x00000007) << 16) |
((dram_para.tpr8 & 0x00000038) << 5) |
((dram_para.tpr8 & 0x000003c0) >> 6),
&mctl_ctl->dramtmg4);
writel(((dram_para.tpr8 & 0x00003c00) << 14) |
((dram_para.tpr8 & 0x0003c000) << 2) |
((dram_para.tpr8 & 0x00fc0000) >> 10) |
((dram_para.tpr8 & 0x0f000000) >> 24),
&mctl_ctl->dramtmg5);
writel(0x00000008, &mctl_ctl->dramtmg8);
writel(((dram_para.tpr8 & 0xf0000000) >> 4) |
((dram_para.tpr9 & 0x00007c00) << 6) |
((dram_para.tpr9 & 0x000003e0) << 3) |
((dram_para.tpr9 & 0x0000001f) >> 0),
&mctl_ctl->pitmg0);
setbits_le32(&mctl_ctl->pitmg1, 0x80000);
writel(((dram_para.tpr9 & 0x003f8000) << 9) | 0x2001,
&mctl_ctl->sched);
writel((dram_para.mr0 << 16) | dram_para.mr1, &mctl_ctl->init3);
writel((dram_para.mr2 << 16) | dram_para.mr3, &mctl_ctl->init4);
writel(0x00000000, &mctl_ctl->pimisc);
writel(0x80000000, &mctl_ctl->upd0);
writel(((dram_para.tpr9 & 0xffc00000) >> 22) |
((dram_para.tpr10 & 0x00000fff) << 16),
&mctl_ctl->rfshtmg);
if (dram_para.tpr13 & 0x20)
writel(0x01040001, &mctl_ctl->mstr);
else
writel(0x01040401, &mctl_ctl->mstr);
if (!(dram_para.tpr13 & 0x20000)) {
writel(0x00000002, &mctl_ctl->pwrctl);
writel(0x00008001, &mctl_ctl->pwrtmg);
}
writel(0x00000001, &mctl_ctl->rfshctl3);
writel(0x00000001, &mctl_ctl->pimisc);
/* deassert dram_clk_cfg reset */
setbits_le32(&ccm->dram_clk_cfg, CCM_DRAMCLK_CFG_RST);
setbits_le32(&mctl_com->ccr, 0x80000);
/* zq stuff */
writel((dram_para.zq >> 8) & 0xff, &mctl_phy->zqcr1);
writel(0x00000003, &mctl_phy->pir);
udelay(10);
mctl_await_completion(&mctl_phy->pgsr0, 0x09, 0x09);
writel(readl(&mctl_phy->zqsr0) | 0x10000000, &mctl_phy->zqcr2);
writel(dram_para.zq & 0xff, &mctl_phy->zqcr1);
/* A23-v1.0 SDK uses 0xfdf3, A23-v2.0 SDK uses 0x5f3 */
writel(0x000005f3, &mctl_phy->pir);
udelay(10);
mctl_await_completion(&mctl_phy->pgsr0, 0x03, 0x03);
if (readl(&mctl_phy->dx1gsr0) & 0x1000000) {
*bus_width = 8;
writel(0, &mctl_phy->dx1gcr);
writel(dram_para.zq & 0xff, &mctl_phy->zqcr1);
writel(0x5f3, &mctl_phy->pir);
udelay(10000);
setbits_le32(&mctl_ctl->mstr, 0x1000);
} else
*bus_width = 16;
correction = (dram_para.odt_en >> 8) & 0xff;
if (correction) {
if (dram_para.odt_en & 0x80000000)
correction = -correction;
mctl_apply_odt_correction(&mctl_phy->dx0lcdlr1, correction);
mctl_apply_odt_correction(&mctl_phy->dx1lcdlr1, correction);
}
mctl_await_completion(&mctl_ctl->statr, 0x01, 0x01);
writel(0x08003e3f, &mctl_phy->pgcr0);
writel(0x00000000, &mctl_ctl->rfshctl3);
}
unsigned long sunxi_dram_init(void)
{
struct sunxi_mctl_com_reg * const mctl_com =
(struct sunxi_mctl_com_reg *)SUNXI_DRAM_COM_BASE;
const u32 columns = 13;
u32 bus, bus_width, offset, page_size, rows;
mctl_sys_init();
mctl_init(&bus_width);
if (bus_width == 16) {
page_size = 8;
bus = 1;
} else {
page_size = 7;
bus = 0;
}
if (!(dram_para.tpr13 & 0x80000000)) {
/* Detect and set rows */
writel(0x000310f4 | MCTL_CR_PAGE_SIZE(page_size),
&mctl_com->cr);
setbits_le32(&mctl_com->swonr, 0x0003ffff);
for (rows = 11; rows < 16; rows++) {
offset = 1 << (rows + columns + bus);
if (mctl_mem_matches(offset))
break;
}
clrsetbits_le32(&mctl_com->cr, MCTL_CR_ROW_MASK,
MCTL_CR_ROW(rows));
} else {
rows = (dram_para.para1 >> 16) & 0xff;
writel(((dram_para.para2 & 0x000000f0) << 11) |
((rows - 1) << 4) |
((dram_para.para1 & 0x0f000000) >> 22) |
0x31000 | MCTL_CR_PAGE_SIZE(page_size),
&mctl_com->cr);
setbits_le32(&mctl_com->swonr, 0x0003ffff);
}
/* Setup DRAM master priority? If this is left out things still work */
writel(0x00000008, &mctl_com->mcr0_0);
writel(0x0001000d, &mctl_com->mcr1_0);
writel(0x00000004, &mctl_com->mcr0_1);
writel(0x00000080, &mctl_com->mcr1_1);
writel(0x00000004, &mctl_com->mcr0_2);
writel(0x00000019, &mctl_com->mcr1_2);
writel(0x00000004, &mctl_com->mcr0_3);
writel(0x00000080, &mctl_com->mcr1_3);
writel(0x00000004, &mctl_com->mcr0_4);
writel(0x01010040, &mctl_com->mcr1_4);
writel(0x00000004, &mctl_com->mcr0_5);
writel(0x0001002f, &mctl_com->mcr1_5);
writel(0x00000004, &mctl_com->mcr0_6);
writel(0x00010020, &mctl_com->mcr1_6);
writel(0x00000004, &mctl_com->mcr0_7);
writel(0x00010020, &mctl_com->mcr1_7);
writel(0x00000008, &mctl_com->mcr0_8);
writel(0x00000001, &mctl_com->mcr1_8);
writel(0x00000008, &mctl_com->mcr0_9);
writel(0x00000005, &mctl_com->mcr1_9);
writel(0x00000008, &mctl_com->mcr0_10);
writel(0x00000003, &mctl_com->mcr1_10);
writel(0x00000008, &mctl_com->mcr0_11);
writel(0x00000005, &mctl_com->mcr1_11);
writel(0x00000008, &mctl_com->mcr0_12);
writel(0x00000003, &mctl_com->mcr1_12);
writel(0x00000008, &mctl_com->mcr0_13);
writel(0x00000004, &mctl_com->mcr1_13);
writel(0x00000008, &mctl_com->mcr0_14);
writel(0x00000002, &mctl_com->mcr1_14);
writel(0x00000008, &mctl_com->mcr0_15);
writel(0x00000003, &mctl_com->mcr1_15);
writel(0x00010138, &mctl_com->bwcr);
return 1 << (rows + columns + bus);
}
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