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mtd: hbmc-am654: Update HyperBus calibration sequence 

Update the HyperBus calibration sequence to fix the instabilities
seen during calibration.The current calibration sequence is same
as described in J721E TRM which is as follows:

1) Ensure FIFO RAM Auto-init is complete
2) Attempt to read 64 bytes of data from CFI region
for 16 iterations and if data is same in 4 successive iterations
then consider Delay Locked Loop(DLL) is stabilized.
3) Verify DLL lock by verifying MDLL_LOCK and SDL_LOCK bit set in
CFG_DLL_STAT register.
4) Confirm calibration by checking for "QRY" string in CFI region.

Also perform minor cleanup and update am654_hyperbus_calibrate()
to return non-zero value on failure.

Signed-off-by: Vaishnav Achath <vaishnav.a@ti.com>
This commit is contained in:
Vaishnav Achath 2023-06-05 19:43:47 +05:30 committed by Praneeth Bajjuri
parent 225211de52
commit be1514f547
1 changed files with 75 additions and 14 deletions
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89
drivers/mtd/hbmc-am654.c
View File

@ -12,27 +12,32 @@
#define FSS_SYSC_REG 0x4
#define HYPERBUS_CALIB_COUNT 25
#define HYPERBUS_CALIB_COUNT 64
#define HYPERBUS_CALIB_MIN_TRIES 48
#define HYPERBUS_CALIB_SUCCESS_COUNT 4
#define HYPERBUS_CALIB_SIZE 64
#define HYPERBUS_CFG_DLL_STAT_REG 4
#define HYPERBUS_CFG_MDLL_LOCK BIT(0)
#define HYPERBUS_CFG_SDLL_LOCK BIT(1)
#define HYPERBUS_CFG_RAM_STAT_REG 8
#define HYPERBUS_CFG_RAM_FIFO_INIT_DONE BIT(0)
struct am654_hbmc_priv {
void __iomem *mmiobase;
void __iomem *cfgregbase;
bool calibrated;
};
/* Calibrate by looking for "QRY" string within the CFI space */
static int am654_hyperbus_calibrate(struct udevice *dev)
/* confirm calibration by looking for "QRY" string within the CFI space */
static int am654_hyperbus_calibrate_check(struct udevice *dev)
{
struct am654_hbmc_priv *priv = dev_get_priv(dev);
int count = HYPERBUS_CALIB_COUNT;
int pass_count = 0;
int ret = -EIO;
u16 qry[3];
if (priv->calibrated)
return 0;
writew(0xF0, priv->mmiobase);
writew(0x98, priv->mmiobase + 0xaa);
while (count--) {
qry[0] = readw(priv->mmiobase + 0x20);
qry[1] = readw(priv->mmiobase + 0x22);
@ -42,13 +47,67 @@ static int am654_hyperbus_calibrate(struct udevice *dev)
pass_count++;
else
pass_count = 0;
if (pass_count == 5)
if (pass_count > HYPERBUS_CALIB_SUCCESS_COUNT)
return 0;
}
return ret;
}
static int am654_hyperbus_calibrate(struct udevice *dev)
{
struct am654_hbmc_priv *priv = dev_get_priv(dev);
char verifybuf[HYPERBUS_CALIB_SIZE];
char rdbuf[HYPERBUS_CALIB_SIZE];
int tries = HYPERBUS_CALIB_COUNT;
int pass_count = 0;
unsigned int reg;
int ret = -EIO;
if (priv->calibrated)
return 0;
if (!priv->cfgregbase || !priv->mmiobase)
return ret;
reg = readl(priv->cfgregbase + HYPERBUS_CFG_RAM_STAT_REG);
if (!(reg & HYPERBUS_CFG_RAM_FIFO_INIT_DONE)) {
dev_err(dev, "Hyperbus RAM FIFO init failed\n");
return ret;
}
writew(0xF0, priv->mmiobase);
writew(0x98, priv->mmiobase + 0xaa);
/*
* Perform calibration by reading 64 bytes from CFI region and
* compare with previously read data, and ensure Delay Locked Loop(DLL)
* is stabilized.
*/
while (tries--) {
memcpy(rdbuf, priv->mmiobase, HYPERBUS_CALIB_SIZE);
if (!memcmp(rdbuf, verifybuf, HYPERBUS_CALIB_SIZE)) {
reg = readl(priv->cfgregbase + HYPERBUS_CFG_DLL_STAT_REG);
if ((reg & HYPERBUS_CFG_MDLL_LOCK) &&
(reg & HYPERBUS_CFG_SDLL_LOCK))
pass_count++;
else
pass_count = 0;
}
memcpy(verifybuf, rdbuf, HYPERBUS_CALIB_SIZE);
if (pass_count > HYPERBUS_CALIB_SUCCESS_COUNT &&
tries < HYPERBUS_CALIB_MIN_TRIES)
break;
}
if (tries > 0)
ret = am654_hyperbus_calibrate_check(dev);
writew(0xF0, priv->mmiobase);
writew(0xFF, priv->mmiobase);
return pass_count == 5;
return ret;
}
static int am654_select_hbmc(struct udevice *dev)
@ -68,7 +127,9 @@ static int am654_hbmc_probe(struct udevice *dev)
struct am654_hbmc_priv *priv = dev_get_priv(dev);
int ret;
priv->mmiobase = devfdt_remap_addr_index(dev, 1);
priv->cfgregbase = devfdt_remap_addr_index(dev, 0);
priv->mmiobase = devfdt_remap_addr_index(dev, 2);
if (dev_read_bool(dev, "mux-controls")) {
ret = am654_select_hbmc(dev);
if (ret) {
@ -79,9 +140,9 @@ static int am654_hbmc_probe(struct udevice *dev)
if (!priv->calibrated) {
ret = am654_hyperbus_calibrate(dev);
if (!ret) {
if (IS_ERR_VALUE(ret)) {
dev_err(dev, "Calibration Failed\n");
return -EIO;
return ret;
}
}
priv->calibrated = true;