Re: [PATCH v6 2/6] spi: cadence-quadspi: Disable the DAC for Intel LGM SoC

From: Ramuthevar, Vadivel MuruganX
Date: Wed Nov 04 2020 - 04:18:51 EST


Hi Pratyush,

Thank you for the review comments...

On 4/11/2020 12:09 am, Pratyush Yadav wrote:
On 30/10/20 01:31PM, Ramuthevar,Vadivel MuruganX wrote:
From: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar@xxxxxxxxxxxxxxx>

On Intel Lightning Mountain(LGM) SoCs QSPI controller do not use
Direct Access Controller(DAC).

This patch adds a quirk to disable the Direct Access Controller
for data transfer instead it uses indirect data transfer.

Signed-off-by: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar@xxxxxxxxxxxxxxx>
---
drivers/spi/spi-cadence-quadspi.c | 12 ++++++++++++
1 file changed, 12 insertions(+)

diff --git a/drivers/spi/spi-cadence-quadspi.c b/drivers/spi/spi-cadence-quadspi.c
index d7b10c46fa70..6d6f7c440ece 100644
--- a/drivers/spi/spi-cadence-quadspi.c
+++ b/drivers/spi/spi-cadence-quadspi.c
@@ -1107,6 +1107,13 @@ static void cqspi_controller_init(struct cqspi_st *cqspi)
writel(reg, cqspi->iobase + CQSPI_REG_CONFIG);
cqspi_controller_enable(cqspi, 1);
+
+ /* Disable direct access controller */
+ if (!cqspi->use_direct_mode) {
+ reg = readl(cqspi->iobase + CQSPI_REG_CONFIG);
+ reg &= ~CQSPI_REG_CONFIG_ENB_DIR_ACC_CTRL;
+ writel(reg, cqspi->iobase + CQSPI_REG_CONFIG);
+ }

You did not address my comment here from last time around [0]. Please
replace this hunk with the one below and test it. Also mention in the
commit message that the DAC bit resets to 1 so there is no need to
explicitly set it.
Really sorry for that, I will add the below patch as you have suggested and test & confirm , thanks!

--- 8< ---
diff --git a/drivers/spi/spi-cadence-quadspi.c
b/drivers/spi/spi-cadence-quadspi.c
index d7ad8b198a11..d2c5d448a944 100644
--- a/drivers/spi/spi-cadence-quadspi.c
+++ b/drivers/spi/spi-cadence-quadspi.c
@@ -2156,10 +2156,12 @@ static void cqspi_controller_init(struct cqspi_st *cqspi)
writel(cqspi->fifo_depth * cqspi->fifo_width / 8,
cqspi->iobase + CQSPI_REG_INDIRECTWRWATERMARK);
- /* Enable Direct Access Controller */
- reg = readl(cqspi->iobase + CQSPI_REG_CONFIG);
- reg |= CQSPI_REG_CONFIG_ENB_DIR_ACC_CTRL;
- writel(reg, cqspi->iobase + CQSPI_REG_CONFIG);
+ /* Disable Direct Access Controller */
+ if (!cqspi->use_dac_mode) {
+ reg = readl(cqspi->iobase + CQSPI_REG_CONFIG);
+ reg &= ~CQSPI_REG_CONFIG_ENB_DIR_ACC_CTRL;
+ writel(reg, cqspi->iobase + CQSPI_REG_CONFIG);
+ }
cqspi_controller_enable(cqspi, 1);
}
--- >8 ---

Same disclaimer as last time: not tested at all.

[0] https://lore.kernel.org/linux-spi/20201022090146.2uj5gfx73dsfumjl@xxxxxx/

PS: Please Cc me in the next revision. I missed 3 revisions in between
because I'm not subscribed to this list. Otherwise I would have sent
this much sooner :-)
Sure, I will add you in cc, btw last 3 revisions I did only Rob's review comments update w.r.t dt_schema.

Regards
Vadivel

}
static int cqspi_request_mmap_dma(struct cqspi_st *cqspi)
@@ -1388,6 +1395,10 @@ static const struct cqspi_driver_platdata am654_ospi = {
.quirks = CQSPI_NEEDS_WR_DELAY,
};
+static const struct cqspi_driver_platdata intel_lgm_qspi = {
+ .quirks = CQSPI_DISABLE_DAC_MODE,
+};
+
static const struct of_device_id cqspi_dt_ids[] = {
{
.compatible = "cdns,qspi-nor",
@@ -1403,6 +1414,7 @@ static const struct of_device_id cqspi_dt_ids[] = {
},
{
.compatible = "intel,lgm-qspi",
+ .data = &intel_lgm_qspi,
},
{ /* end of table */ }
};
--
2.11.0