[U-Boot] [PATCH 14/23] powerpc/t4240qds: Add voltage ID support
York Sun
yorksun at freescale.com
Fri Mar 22 18:15:22 CET 2013
T4240 has voltage ID fuse. Read the fuse and configure the voltage
correctly. Core voltage has higher tolerance on over side than below.
Signed-off-by: York Sun <yorksun at freescale.com>
---
board/freescale/t4qds/t4qds.c | 230 +++++++++++++++++++++++++++++++++++++++++
include/configs/t4qds.h | 12 ++-
2 files changed, 240 insertions(+), 2 deletions(-)
diff --git a/board/freescale/t4qds/t4qds.c b/board/freescale/t4qds/t4qds.c
index e8c6998..78322df 100644
--- a/board/freescale/t4qds/t4qds.c
+++ b/board/freescale/t4qds/t4qds.c
@@ -132,6 +132,229 @@ int select_i2c_ch_pca9547(u8 ch)
return 0;
}
+/*
+ * read_voltage from sensor on I2C bus
+ * We use average of 4 readings, waiting for 532us befor another reading
+ */
+#define NUM_READINGS 4 /* prefer to be power of 2 for efficiency */
+#define WAIT_FOR_ADC 532 /* wait for 532 microseconds for ADC */
+
+static inline int read_voltage(void)
+{
+ int i, ret, voltage_read = 0;
+ u16 vol_mon;
+
+ for (i = 0; i < NUM_READINGS; i++) {
+ ret = i2c_read(I2C_VOL_MONITOR_ADDR,
+ I2C_VOL_MONITOR_BUS_V_OFFSET, 1, (void *)&vol_mon, 2);
+ if (ret) {
+ printf("VID: failed to read core voltage\n");
+ return ret;
+ }
+ if (vol_mon & I2C_VOL_MONITOR_BUS_V_OVF) {
+ printf("VID: Core voltage sensor error\n");
+ return -1;
+ }
+ debug("VID: bus voltage reads 0x%04x\n", vol_mon);
+ /* LSB = 4mv */
+ voltage_read += (vol_mon >> I2C_VOL_MONITOR_BUS_V_SHIFT) * 4;
+ udelay(WAIT_FOR_ADC);
+ }
+ /* calculate the average */
+ voltage_read /= NUM_READINGS;
+
+ return voltage_read;
+}
+
+/*
+ * We need to calculate how long before the voltage starts to drop or increase
+ * It returns with the loop count. Each loop takes several readings (532us)
+ */
+static inline int wait_for_voltage_change(int vdd_last)
+{
+ int timeout, vdd_current;
+
+ vdd_current = read_voltage();
+ /* wait until voltage starts to drop */
+ for (timeout = 0; abs(vdd_last - vdd_current) <= 4 &&
+ timeout < 100; timeout++) {
+ vdd_current = read_voltage();
+ }
+ if (timeout >= 100) {
+ printf("VID: Voltage adjustment timeout\n");
+ return -1;
+ }
+ return timeout;
+}
+
+/*
+ * argument 'wait' is the time we know the voltage difference can be measured
+ * this function keeps reading the voltage until it is stable
+ */
+static inline int wait_for_voltage_stable(int wait)
+{
+ int timeout, vdd_current, vdd_last;
+
+ vdd_last = read_voltage();
+ udelay(wait * NUM_READINGS * WAIT_FOR_ADC);
+ /* wait until voltage is stable */
+ vdd_current = read_voltage();
+ for (timeout = 0; abs(vdd_last - vdd_current) >= 4 &&
+ timeout < 100; timeout++) {
+ vdd_last = vdd_current;
+ udelay(wait * NUM_READINGS * WAIT_FOR_ADC);
+ vdd_current = read_voltage();
+ }
+ if (timeout >= 100) {
+ printf("VID: Voltage adjustment timeout\n");
+ return -1;
+ }
+
+ return vdd_current;
+}
+
+static inline int set_voltage(u8 vid)
+{
+ int wait, vdd_last;
+
+ vdd_last = read_voltage();
+ QIXIS_WRITE(brdcfg[6], vid);
+ wait = wait_for_voltage_change(vdd_last);
+ if (wait < 0)
+ return -1;
+ debug("VID: Waited %d us\n", wait * NUM_READINGS * WAIT_FOR_ADC);
+ wait = wait ? wait : 1;
+
+ vdd_last = wait_for_voltage_stable(wait);
+ if (vdd_last < 0)
+ return -1;
+ debug("VID: Current voltage is %d mV\n", vdd_last);
+
+ return vdd_last;
+}
+
+
+static int adjust_vdd(void)
+{
+ int re_enable = disable_interrupts();
+ ccsr_gur_t __iomem *gur =
+ (void __iomem *)(CONFIG_SYS_MPC85xx_GUTS_ADDR);
+ u32 fusesr;
+ u8 vid, vid_current;
+ int vdd_target, vdd_current, vdd_last;
+ int ret;
+ static const uint16_t vdd[32] = {
+ 0, /* unused */
+ 9875, /* 0.9875V */
+ 9750,
+ 9625,
+ 9500,
+ 9375,
+ 9250,
+ 9125,
+ 9000,
+ 8875,
+ 8750,
+ 8625,
+ 8500,
+ 8375,
+ 8250,
+ 8125,
+ 10000, /* 1.0000V */
+ 10125,
+ 10250,
+ 10375,
+ 10500,
+ 10625,
+ 10750,
+ 10875,
+ 11000,
+ 0, /* reserved */
+ };
+ struct vdd_drive {
+ u8 vid;
+ unsigned voltage;
+ };
+
+ ret = select_i2c_ch_pca9547(I2C_MUX_CH_VOL_MONITOR);
+ if (ret) {
+ debug("VID: I2c failed to switch channel\n");
+ ret = -1;
+ goto exit;
+ }
+
+ /* get the voltage ID from fuse status register */
+ fusesr = in_be32(&gur->dcfg_fusesr);
+ vid = (fusesr >> FSL_CORENET_DCFG_FUSESR_VID_SHIFT) &
+ FSL_CORENET_DCFG_FUSESR_VID_MASK;
+ if (vid == FSL_CORENET_DCFG_FUSESR_VID_MASK) {
+ vid = (fusesr >> FSL_CORENET_DCFG_FUSESR_ALTVID_SHIFT) &
+ FSL_CORENET_DCFG_FUSESR_ALTVID_MASK;
+ }
+ vdd_target = vdd[vid];
+ if (vdd_target == 0) {
+ debug("VID: VID not used\n");
+ ret = 0;
+ goto exit;
+ } else {
+ /* round up and divice by 10 to get a value in mV */
+ vdd_target = DIV_ROUND_UP(vdd_target, 10);
+ debug("VID: vid = %d mV\n", vdd_target);
+ }
+
+ /*
+ * Check current board VID setting
+ * Voltage regulator support output to 6.250mv step
+ * The highes voltage allowed for this board is (vid=0x40) 1.21250V
+ * the lowest is (vid=0x7f) 0.81875V
+ */
+ vid_current = QIXIS_READ(brdcfg[6]);
+ vdd_current = 121250 - (vid_current - 0x40) * 625;
+ debug("VID: Current vid setting is (0x%x) %d mV\n",
+ vid_current, vdd_current/100);
+
+ /*
+ * Read voltage monitor to check real voltage.
+ * Voltage monitor LSB is 4mv.
+ */
+ vdd_last = read_voltage();
+ if (vdd_last < 0) {
+ printf("VID: Could not read voltage sensor "
+ "abort VID adjustment\n");
+ ret = -1;
+ goto exit;
+ }
+ debug("VID: Core voltage is at %d mV\n", vdd_last);
+ /*
+ * Adjust voltage to at or 8mV above target.
+ * Each step of adjustment is 6.25mV.
+ * Stepping down too fast may cause over current.
+ */
+ while (vdd_last > 0 && vid_current < 0x80 &&
+ vdd_last > (vdd_target + 8)) {
+ vid_current++;
+ vdd_last = set_voltage(vid_current);
+ }
+ /*
+ * Check if we need to step up
+ * This happens when board voltage switch was set too low
+ */
+ while (vdd_last > 0 && vid_current >= 0x40 &&
+ vdd_last < vdd_target + 2) {
+ vid_current--;
+ vdd_last = set_voltage(vid_current);
+ }
+ if (vdd_last > 0)
+ printf("VID: Core voltage %d mV\n", vdd_last);
+ else
+ ret = -1;
+
+exit:
+ if (re_enable)
+ enable_interrupts();
+ return ret;
+}
+
/* Configure Crossbar switches for Front-Side SerDes Ports */
int config_frontside_crossbar_vsc3316(void)
{
@@ -285,6 +508,13 @@ int board_early_init_r(void)
/* Disable remote I2C connectoin */
QIXIS_WRITE(brdcfg[5], BRDCFG5_RESET);
+ /*
+ * Adjust core voltage according to voltage ID
+ * This function changes I2C mux to channel 2.
+ */
+ if (adjust_vdd())
+ printf("Warning: Adjusting core voltage failed.\n");
+
/* Configure board SERDES ports crossbar */
config_frontside_crossbar_vsc3316();
config_backside_crossbar_mux();
diff --git a/include/configs/t4qds.h b/include/configs/t4qds.h
index c5110c2..dbaa7ea 100644
--- a/include/configs/t4qds.h
+++ b/include/configs/t4qds.h
@@ -444,11 +444,19 @@ unsigned long get_board_ddr_clk(void);
#define I2C_MUX_PCA_ADDR_PRI 0x77 /* I2C bus multiplexer,primary */
#define I2C_MUX_PCA_ADDR_SEC 0x76 /* I2C bus multiplexer,secondary */
-/* VSC Crossbar switches */
-#define CONFIG_VSC_CROSSBAR
#define I2C_MUX_CH_DEFAULT 0x8
+#define I2C_MUX_CH_VOL_MONITOR 0xa
#define I2C_MUX_CH_VSC3316_FS 0xc
#define I2C_MUX_CH_VSC3316_BS 0xd
+
+/* Voltage monitor on channel 2*/
+#define I2C_VOL_MONITOR_ADDR 0x40
+#define I2C_VOL_MONITOR_BUS_V_OFFSET 0x2
+#define I2C_VOL_MONITOR_BUS_V_OVF 0x1
+#define I2C_VOL_MONITOR_BUS_V_SHIFT 3
+
+/* VSC Crossbar switches */
+#define CONFIG_VSC_CROSSBAR
#define VSC3316_FSM_TX_ADDR 0x70
#define VSC3316_FSM_RX_ADDR 0x71
--
1.7.9.5
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