Re: [PATCH 4/4] mci: dwcmshc-sdhci: add support for Kalray Coolidge v2 SoC eMMC controller

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Hello Ahmad,

On 2/29/24 17:19, Ahmad Fatoum wrote:
Hello Yann,

On 29.02.24 16:57, Yann Sionneau wrote:
Kalray Coolidge v2 SoC eMMC controller needs static tx delay tuning even
for basic standard or high speed modes.

This patch also adds possibility to do some vendor specific tuning
in set_ios().
This will be needed for Coolidge v2 for >50 MHz speeds and HS200/HS400

Signed-off-by: Yann Sionneau <ysionneau@xxxxxxxxxxxxx>
  drivers/mci/dwcmshc-sdhci.c | 40 +++++++++++++++++++++++++++++++++++++
  1 file changed, 40 insertions(+)

diff --git a/drivers/mci/dwcmshc-sdhci.c b/drivers/mci/dwcmshc-sdhci.c
index d9c51752db..5017a1f56e 100644
--- a/drivers/mci/dwcmshc-sdhci.c
+++ b/drivers/mci/dwcmshc-sdhci.c
@@ -9,11 +9,16 @@
  #include <dma.h>
  #include <malloc.h>
  #include <mci.h>
+#include <of_device.h>
  #include <linux/err.h>
  #include <linux/clk.h>
#include "sdhci.h" +#define tx_delay_static_cfg(delay) (delay << 5)
+#define tx_tuning_clk_sel(delay)        (delay)
+#define DWCMSHC_GPIO_OUT  0x34 /* offset from vendor specific area */
  #define CARD_STATUS_MASK (0x1e00)
  #define CARD_STATUS_TRAN (4 << 9)
@@ -22,6 +27,13 @@ static int do_send_cmd(struct mci_host *mci, struct mci_cmd *cmd, struct mci_dat
  struct dwcmshc_host {
  	struct mci_host mci;
  	struct sdhci sdhci;
+	int vendor_specific_area;
+	const struct dwcmshc_callbacks *cb;
+struct dwcmshc_callbacks {
+	void (*init)(struct mci_host *mci, struct device *dev);
Why is dev needed? There's already mci->hw_dev and mci->mci->dev

dev is not needed per se, but I thought that since the callback is used to extend dwcmshc_mci_init() called from generic code:

Then it would be a good idea to provide the same arguments.

But I can remove it.

+	void (*set_ios)(struct mci_host *mci, struct mci_ios *ios);
You don't actually use set_ios. But I assume you intend to add in future?
Maybe add it when it's actually needed?

Ok indeed it's for the future, in the future to support HS200/HS400 high speed modes

vendor specific tuning (tx/rx delay lines tuning) would take place in such callback.

+static void dwcmshc_coolidgev2_init(struct mci_host *mci, struct device *dev)
+	struct dwcmshc_host *host = priv_from_mci_host(mci);
+	// configure TX delay to set correct setup/hold for Coolidge V2
Nite: If you are going to send v2, please change into /* */ comments
for uniformity.


+	sdhci_write32(&host->sdhci,
+		      host->vendor_specific_area + DWCMSHC_GPIO_OUT,
+		      tx_delay_static_cfg(0xf) | tx_tuning_clk_sel(4));
+struct dwcmshc_callbacks kalray_coolidgev2_callbacks = {
+	.init = dwcmshc_coolidgev2_init,
  static struct of_device_id dwcmshc_dt_ids[] = {
  	{ .compatible = "snps,dwcmshc-sdhci", },
+	{ .compatible = "kalray,coolidge-v2-dwcmshc-sdhci", .data = &kalray_coolidgev2_callbacks },
  	{ }

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