From: Cédric Le Goater <clg@kaod.org>
When doing calibration, the SPI clock rate in the CE0 Control Register
and the read delay cycles in the Read Timing Compensation Register are
set using bit[11:4] of the DMA Control Register.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Acked-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20190904070506.1052-7-clg@kaod.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
hw/ssi/aspeed_smc.c | 64 ++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 63 insertions(+), 1 deletion(-)
diff --git a/hw/ssi/aspeed_smc.c b/hw/ssi/aspeed_smc.c
index c1a45c10dc1..7a0cd7607fd 100644
@@ -77,6 +77,10 @@
#define CTRL_CMD_MASK 0xff
#define CTRL_DUMMY_HIGH_SHIFT 14
#define CTRL_AST2400_SPI_4BYTE (1 << 13)
+#define CE_CTRL_CLOCK_FREQ_SHIFT 8
+#define CE_CTRL_CLOCK_FREQ_MASK 0xf
+#define CE_CTRL_CLOCK_FREQ(div) \
+ (((div) & CE_CTRL_CLOCK_FREQ_MASK) << CE_CTRL_CLOCK_FREQ_SHIFT)
#define CTRL_DUMMY_LOW_SHIFT 6 /* 2 bits [7:6] */
#define CTRL_CE_STOP_ACTIVE (1 << 2)
#define CTRL_CMD_MODE_MASK 0x3
@@ -112,7 +116,7 @@
#define DMA_CTRL_DELAY_SHIFT 8
#define DMA_CTRL_FREQ_MASK 0xf
#define DMA_CTRL_FREQ_SHIFT 4
-#define DMA_CTRL_MODE (1 << 3)
+#define DMA_CTRL_CALIB (1 << 3)
#define DMA_CTRL_CKSUM (1 << 2)
#define DMA_CTRL_WRITE (1 << 1)
#define DMA_CTRL_ENABLE (1 << 0)
@@ -811,6 +815,60 @@ static uint64_t aspeed_smc_read(void *opaque, hwaddr addr, unsigned int size)
}
}
+static uint8_t aspeed_smc_hclk_divisor(uint8_t hclk_mask)
+{
+ /* HCLK/1 .. HCLK/16 */
+ const uint8_t hclk_divisors[] = {
+ 15, 7, 14, 6, 13, 5, 12, 4, 11, 3, 10, 2, 9, 1, 8, 0
+ };
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(hclk_divisors); i++) {
+ if (hclk_mask == hclk_divisors[i]) {
+ return i + 1;
+ }
+ }
+
+ qemu_log_mask(LOG_GUEST_ERROR, "invalid HCLK mask %x", hclk_mask);
+ return 0;
+}
+
+/*
+ * When doing calibration, the SPI clock rate in the CE0 Control
+ * Register and the read delay cycles in the Read Timing Compensation
+ * Register are set using bit[11:4] of the DMA Control Register.
+ */
+static void aspeed_smc_dma_calibration(AspeedSMCState *s)
+{
+ uint8_t delay =
+ (s->regs[R_DMA_CTRL] >> DMA_CTRL_DELAY_SHIFT) & DMA_CTRL_DELAY_MASK;
+ uint8_t hclk_mask =
+ (s->regs[R_DMA_CTRL] >> DMA_CTRL_FREQ_SHIFT) & DMA_CTRL_FREQ_MASK;
+ uint8_t hclk_div = aspeed_smc_hclk_divisor(hclk_mask);
+ uint32_t hclk_shift = (hclk_div - 1) << 2;
+ uint8_t cs;
+
+ /*
+ * The Read Timing Compensation Register values apply to all CS on
+ * the SPI bus and only HCLK/1 - HCLK/5 can have tunable delays
+ */
+ if (hclk_div && hclk_div < 6) {
+ s->regs[s->r_timings] &= ~(0xf << hclk_shift);
+ s->regs[s->r_timings] |= delay << hclk_shift;
+ }
+
+ /*
+ * TODO: compute the CS from the DMA address and the segment
+ * registers. This is not really a problem for now because the
+ * Timing Register values apply to all CS and software uses CS0 to
+ * do calibration.
+ */
+ cs = 0;
+ s->regs[s->r_ctrl0 + cs] &=
+ ~(CE_CTRL_CLOCK_FREQ_MASK << CE_CTRL_CLOCK_FREQ_SHIFT);
+ s->regs[s->r_ctrl0 + cs] |= CE_CTRL_CLOCK_FREQ(hclk_div);
+}
+
/*
* Accumulate the result of the reads to provide a checksum that will
* be used to validate the read timing settings.
@@ -826,6 +884,10 @@ static void aspeed_smc_dma_checksum(AspeedSMCState *s)
return;
}
+ if (s->regs[R_DMA_CTRL] & DMA_CTRL_CALIB) {
+ aspeed_smc_dma_calibration(s);
+ }
+
while (s->regs[R_DMA_LEN]) {
data = address_space_ldl_le(&s->flash_as, s->regs[R_DMA_FLASH_ADDR],
MEMTXATTRS_UNSPECIFIED, &result);
--
2.20.1