[RFC PATCH 4/6] spi: cadence-qspi: Use PHY for DAC reads if possible
Pratyush Yadav
p.yadav at ti.com
Thu Mar 11 19:12:14 GMT 2021
Check if a read is eligible for PHY and if it is, enable PHY and DQS.
Since PHY reads only work at an address that is 16-byte aligned and of
size that is a multiple of 16 bytes, read the starting and ending
unaligned portions without PHY, and only enable PHY for the middle part.
Signed-off-by: Pratyush Yadav <p.yadav at ti.com>
---
drivers/spi/spi-cadence-quadspi.c | 203 ++++++++++++++++++++++++++----
1 file changed, 182 insertions(+), 21 deletions(-)
diff --git a/drivers/spi/spi-cadence-quadspi.c b/drivers/spi/spi-cadence-quadspi.c
index e2d6ea833423..e64d8e125263 100644
--- a/drivers/spi/spi-cadence-quadspi.c
+++ b/drivers/spi/spi-cadence-quadspi.c
@@ -41,19 +41,27 @@
struct cqspi_st;
+struct phy_setting {
+ u8 rx;
+ u8 tx;
+ u8 read_delay;
+};
+
struct cqspi_flash_pdata {
- struct cqspi_st *cqspi;
- u32 clk_rate;
- u32 read_delay;
- u32 tshsl_ns;
- u32 tsd2d_ns;
- u32 tchsh_ns;
- u32 tslch_ns;
- u8 inst_width;
- u8 addr_width;
- u8 data_width;
- bool dtr;
- u8 cs;
+ struct cqspi_st *cqspi;
+ u32 clk_rate;
+ u32 read_delay;
+ u32 tshsl_ns;
+ u32 tsd2d_ns;
+ u32 tchsh_ns;
+ u32 tslch_ns;
+ u8 inst_width;
+ u8 addr_width;
+ u8 data_width;
+ bool dtr;
+ u8 cs;
+ bool use_phy;
+ struct phy_setting phy_setting;
};
struct cqspi_st {
@@ -108,12 +116,14 @@ struct cqspi_driver_platdata {
/* Register map */
#define CQSPI_REG_CONFIG 0x00
#define CQSPI_REG_CONFIG_ENABLE_MASK BIT(0)
+#define CQSPI_REG_CONFIG_PHY_EN BIT(3)
#define CQSPI_REG_CONFIG_ENB_DIR_ACC_CTRL BIT(7)
#define CQSPI_REG_CONFIG_DECODE_MASK BIT(9)
#define CQSPI_REG_CONFIG_CHIPSELECT_LSB 10
#define CQSPI_REG_CONFIG_DMA_MASK BIT(15)
#define CQSPI_REG_CONFIG_BAUD_LSB 19
#define CQSPI_REG_CONFIG_DTR_PROTO BIT(24)
+#define CQSPI_REG_CONFIG_PHY_PIPELINE BIT(25)
#define CQSPI_REG_CONFIG_DUAL_OPCODE BIT(30)
#define CQSPI_REG_CONFIG_IDLE_LSB 31
#define CQSPI_REG_CONFIG_CHIPSELECT_MASK 0xF
@@ -150,6 +160,7 @@ struct cqspi_driver_platdata {
#define CQSPI_REG_READCAPTURE_BYPASS_LSB 0
#define CQSPI_REG_READCAPTURE_DELAY_LSB 1
#define CQSPI_REG_READCAPTURE_DELAY_MASK 0xF
+#define CQSPI_REG_READCAPTURE_DQS_LSB 8
#define CQSPI_REG_SIZE 0x14
#define CQSPI_REG_SIZE_ADDRESS_LSB 0
@@ -999,6 +1010,7 @@ static void cqspi_config_baudrate_div(struct cqspi_st *cqspi)
static void cqspi_readdata_capture(struct cqspi_st *cqspi,
const bool bypass,
+ const bool dqs,
const unsigned int delay)
{
void __iomem *reg_base = cqspi->iobase;
@@ -1017,6 +1029,11 @@ static void cqspi_readdata_capture(struct cqspi_st *cqspi,
reg |= (delay & CQSPI_REG_READCAPTURE_DELAY_MASK)
<< CQSPI_REG_READCAPTURE_DELAY_LSB;
+ if (dqs)
+ reg |= (1 << CQSPI_REG_READCAPTURE_DQS_LSB);
+ else
+ reg &= ~(1 << CQSPI_REG_READCAPTURE_DQS_LSB);
+
writel(reg, reg_base + CQSPI_REG_READCAPTURE);
}
@@ -1035,6 +1052,64 @@ static void cqspi_controller_enable(struct cqspi_st *cqspi, bool enable)
writel(reg, reg_base + CQSPI_REG_CONFIG);
}
+static void cqspi_phy_enable(struct cqspi_flash_pdata *f_pdata, bool enable)
+{
+ struct cqspi_st *cqspi = f_pdata->cqspi;
+ void __iomem *reg_base = cqspi->iobase;
+ u32 reg;
+ u8 dummy;
+
+ if (enable) {
+ cqspi_readdata_capture(cqspi, 1, true,
+ f_pdata->phy_setting.read_delay);
+
+ reg = readl(reg_base + CQSPI_REG_CONFIG);
+ reg |= CQSPI_REG_CONFIG_PHY_EN |
+ CQSPI_REG_CONFIG_PHY_PIPELINE;
+ writel(reg, reg_base + CQSPI_REG_CONFIG);
+
+ /*
+ * Reduce dummy cycle by 1. This is a requirement of PHY mode
+ * operation for correctly reading the data.
+ */
+ reg = readl(reg_base + CQSPI_REG_RD_INSTR);
+ dummy = (reg >> CQSPI_REG_RD_INSTR_DUMMY_LSB) &
+ CQSPI_REG_RD_INSTR_DUMMY_MASK;
+ dummy--;
+ reg &= ~(CQSPI_REG_RD_INSTR_DUMMY_MASK <<
+ CQSPI_REG_RD_INSTR_DUMMY_LSB);
+
+ reg |= (dummy & CQSPI_REG_RD_INSTR_DUMMY_MASK)
+ << CQSPI_REG_RD_INSTR_DUMMY_LSB;
+ writel(reg, reg_base + CQSPI_REG_RD_INSTR);
+ } else {
+ cqspi_readdata_capture(cqspi, !cqspi->rclk_en, false,
+ f_pdata->read_delay);
+
+ reg = readl(reg_base + CQSPI_REG_CONFIG);
+ reg &= ~(CQSPI_REG_CONFIG_PHY_EN |
+ CQSPI_REG_CONFIG_PHY_PIPELINE);
+ writel(reg, reg_base + CQSPI_REG_CONFIG);
+
+ /*
+ * Dummy cycles were decremented when enabling PHY. Increment
+ * dummy cycle by 1 to restore the original value.
+ */
+ reg = readl(reg_base + CQSPI_REG_RD_INSTR);
+ dummy = (reg >> CQSPI_REG_RD_INSTR_DUMMY_LSB) &
+ CQSPI_REG_RD_INSTR_DUMMY_MASK;
+ dummy++;
+ reg &= ~(CQSPI_REG_RD_INSTR_DUMMY_MASK <<
+ CQSPI_REG_RD_INSTR_DUMMY_LSB);
+
+ reg |= (dummy & CQSPI_REG_RD_INSTR_DUMMY_MASK)
+ << CQSPI_REG_RD_INSTR_DUMMY_LSB;
+ writel(reg, reg_base + CQSPI_REG_RD_INSTR);
+ }
+
+ cqspi_wait_idle(cqspi);
+}
+
static void cqspi_configure(struct cqspi_flash_pdata *f_pdata,
unsigned long sclk)
{
@@ -1056,7 +1131,7 @@ static void cqspi_configure(struct cqspi_flash_pdata *f_pdata,
cqspi->sclk = sclk;
cqspi_config_baudrate_div(cqspi);
cqspi_delay(f_pdata);
- cqspi_readdata_capture(cqspi, !cqspi->rclk_en,
+ cqspi_readdata_capture(cqspi, !cqspi->rclk_en, false,
f_pdata->read_delay);
}
@@ -1098,6 +1173,39 @@ static ssize_t cqspi_write(struct cqspi_flash_pdata *f_pdata,
return cqspi_indirect_write_execute(f_pdata, to, buf, len);
}
+/*
+ * Check if PHY mode can be used on the given op. This is assuming it will be a
+ * DAC mode read, since PHY won't work on any other type of operation anyway.
+ */
+static bool cqspi_phy_op_eligible(const struct spi_mem_op *op)
+{
+ /* PHY is only tuned for 8D-8D-8D. */
+ if (!(op->cmd.dtr && op->addr.dtr && op->dummy.dtr && op->data.dtr))
+ return false;
+ if (op->cmd.buswidth != 8)
+ return false;
+ if (op->addr.nbytes && op->addr.buswidth != 8)
+ return false;
+ if (op->dummy.nbytes && op->dummy.buswidth != 8)
+ return false;
+ if (op->data.nbytes && op->data.buswidth != 8)
+ return false;
+
+ return true;
+}
+
+static bool cqspi_use_phy(struct cqspi_flash_pdata *f_pdata,
+ const struct spi_mem_op *op)
+{
+ if (!f_pdata->use_phy)
+ return false;
+
+ if (op->data.nbytes < 16)
+ return false;
+
+ return cqspi_phy_op_eligible(op);
+}
+
static void cqspi_rx_dma_callback(void *param)
{
struct cqspi_st *cqspi = param;
@@ -1105,8 +1213,8 @@ static void cqspi_rx_dma_callback(void *param)
complete(&cqspi->rx_dma_complete);
}
-static int cqspi_direct_read_execute(struct cqspi_flash_pdata *f_pdata,
- u_char *buf, loff_t from, size_t len)
+static int cqspi_direct_read_dma(struct cqspi_flash_pdata *f_pdata,
+ u_char *buf, loff_t from, size_t len)
{
struct cqspi_st *cqspi = f_pdata->cqspi;
struct device *dev = &cqspi->pdev->dev;
@@ -1118,11 +1226,6 @@ static int cqspi_direct_read_execute(struct cqspi_flash_pdata *f_pdata,
dma_addr_t dma_dst;
struct device *ddev;
- if (!cqspi->rx_chan || !virt_addr_valid(buf)) {
- memcpy_fromio(buf, cqspi->ahb_base + from, len);
- return 0;
- }
-
ddev = cqspi->rx_chan->device->dev;
dma_dst = dma_map_single(ddev, buf, len, DMA_FROM_DEVICE);
if (dma_mapping_error(ddev, dma_dst)) {
@@ -1164,6 +1267,64 @@ static int cqspi_direct_read_execute(struct cqspi_flash_pdata *f_pdata,
return ret;
}
+static int cqspi_direct_read_execute(struct cqspi_flash_pdata *f_pdata,
+ const struct spi_mem_op *op)
+{
+ struct cqspi_st *cqspi = f_pdata->cqspi;
+ loff_t from = op->addr.val;
+ loff_t from_aligned, to_aligned;
+ size_t len = op->data.nbytes;
+ size_t len_aligned;
+ u_char *buf = op->data.buf.in;
+ int ret;
+
+ if (!cqspi->rx_chan || !virt_addr_valid(buf)) {
+ memcpy_fromio(buf, cqspi->ahb_base + from, len);
+ return 0;
+ }
+
+ if (!cqspi_use_phy(f_pdata, op))
+ return cqspi_direct_read_dma(f_pdata, buf, from, len);
+
+ /*
+ * PHY reads must be 16-byte aligned, and they must be a multiple of 16
+ * bytes.
+ */
+ from_aligned = (from + 0xF) & ~0xF;
+ to_aligned = (from + len) & ~0xF;
+ len_aligned = to_aligned - from_aligned;
+
+ /* Read the unaligned part at the start. */
+ if (from != from_aligned) {
+ ret = cqspi_direct_read_dma(f_pdata, buf, from,
+ from_aligned - from);
+ if (ret)
+ return ret;
+ buf += from_aligned - from;
+ }
+
+ if (len_aligned) {
+ cqspi_phy_enable(f_pdata, true);
+ ret = cqspi_direct_read_dma(f_pdata, buf, from_aligned,
+ len_aligned);
+ cqspi_phy_enable(f_pdata, false);
+ if (ret)
+ return ret;
+ buf += len_aligned;
+ }
+
+ /* Now read the remaining part, if any. */
+ if (to_aligned != (from + len)) {
+ ret = cqspi_direct_read_dma(f_pdata, buf, to_aligned,
+ (from + len) - to_aligned);
+ if (ret)
+ return ret;
+ buf += (from + len) - to_aligned;
+ }
+
+ return 0;
+}
+
static ssize_t cqspi_read(struct cqspi_flash_pdata *f_pdata,
const struct spi_mem_op *op)
{
@@ -1182,7 +1343,7 @@ static ssize_t cqspi_read(struct cqspi_flash_pdata *f_pdata,
return ret;
if (cqspi->use_direct_mode && ((from + len) <= cqspi->ahb_size))
- return cqspi_direct_read_execute(f_pdata, buf, from, len);
+ return cqspi_direct_read_execute(f_pdata, op);
return cqspi_indirect_read_execute(f_pdata, buf, from, len);
}
--
2.30.0
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