commit 2fcc3ba1b766df5f8cfbf35cb2cc88edff94d0f3
author Tom Warren <twarren@nvidia.com> Mon Nov 25 14:43:50 2019 -0700
committer Tom Warren <twarren@nvidia.com> Thu Apr 02 14:30:02 2020 -0700
tree a493f81731c7b92c939cb4a600d72537a47068e1
parent 3c8cf240322e76eebbb31593c96f0754092df91f

qspi: t210: Fix QSPI clock and tap delays

When claim_bus was setting the clock, it reset the QSPI controller,
which wipes out any tap delays set by previous bootloaders (nvtboot,
CBoot for example on Nano). Instead of doing that in claim_bus, which
gets called a lot, moved clock setting to probe(), and set tap delays
there, too. Also updated clock to 80MHz to match CBoot. Now QSPI env
save works reliably again.

Signed-off-by: Tom Warren <twarren@nvidia.com>

drivers/spi/tegra210_qspi.c

diff --git a/drivers/spi/tegra210_qspi.c b/drivers/spi/tegra210_qspi.c
index 2a77126..d914337 100644
--- a/drivers/spi/tegra210_qspi.c
+++ b/drivers/spi/tegra210_qspi.c
@@ -42,10 +42,10 @@
 #define QSPI_CMD1_BITLEN_SHIFT		0
 
 /* COMMAND2 */
-#define QSPI_CMD2_TX_CLK_TAP_DELAY	BIT(6)
-#define QSPI_CMD2_TX_CLK_TAP_DELAY_MASK	GENMASK(11,6)
-#define QSPI_CMD2_RX_CLK_TAP_DELAY	BIT(0)
-#define QSPI_CMD2_RX_CLK_TAP_DELAY_MASK	GENMASK(5,0)
+#define QSPI_CMD2_TX_CLK_TAP_DELAY_SHIFT	10
+#define QSPI_CMD2_TX_CLK_TAP_DELAY_MASK	GENMASK(14,10)
+#define QSPI_CMD2_RX_CLK_TAP_DELAY_SHIFT	0
+#define QSPI_CMD2_RX_CLK_TAP_DELAY_MASK	GENMASK(7,0)
 
 /* TRANSFER STATUS */
 #define QSPI_XFER_STS_RDY		BIT(30)
@@ -111,9 +111,9 @@
 
 	/* Use 500KHz as a suitable default */
 	plat->frequency = fdtdec_get_int(blob, node, "spi-max-frequency",
-					500000);
+					 500000);
 	plat->deactivate_delay_us = fdtdec_get_int(blob, node,
-					"spi-deactivate-delay", 0);
+						   "spi-deactivate-delay", 0);
 	debug("%s: base=%#08lx, periph_id=%d, max-frequency=%d, deactivate_delay=%d\n",
 	      __func__, plat->base, plat->periph_id, plat->frequency,
 	      plat->deactivate_delay_us);
@@ -127,14 +127,23 @@
 	struct tegra210_qspi_priv *priv = dev_get_priv(bus);
 
 	priv->regs = (struct qspi_regs *)plat->base;
+	struct qspi_regs *regs = priv->regs;
 
 	priv->last_transaction_us = timer_get_us();
 	priv->freq = plat->frequency;
 	priv->periph_id = plat->periph_id;
 
+	debug("%s: Freq = %u, id = %d\n", __func__, priv->freq,
+	      priv->periph_id);
 	/* Change SPI clock to correct frequency, PLLP_OUT0 source */
 	clock_start_periph_pll(priv->periph_id, CLOCK_ID_PERIPH, priv->freq);
 
+	/* Set tap delays here, clock change above resets QSPI controller */
+	u32 reg = (0x09 << QSPI_CMD2_TX_CLK_TAP_DELAY_SHIFT) |
+		   (0x0C << QSPI_CMD2_RX_CLK_TAP_DELAY_SHIFT);
+	writel(reg, &regs->command2);
+	debug("%s: COMMAND2 = %08x\n", __func__, readl(&regs->command2));
+
 	return 0;
 }
 
@@ -144,9 +153,6 @@
 	struct tegra210_qspi_priv *priv = dev_get_priv(bus);
 	struct qspi_regs *regs = priv->regs;
 
-	/* Change SPI clock to correct frequency, PLLP_OUT0 source */
-	clock_start_periph_pll(priv->periph_id, CLOCK_ID_PERIPH, priv->freq);
-
 	debug("%s: FIFO STATUS = %08x\n", __func__, readl(&regs->fifo_status));
 
 	/* Set master mode and sw controlled CS */