On 2/16/2024 12:47 AM, Ulf Hansson wrote:
On Thu, 15 Feb 2024 at 12:03, Yang Xiwen via B4 Relay
<devnull+forbidden405.outlook.com@xxxxxxxxxx> wrote:
From: Yang Xiwen <forbidden405@xxxxxxxxxxx>
Parsing dt usaully happens very early, sometimes even bofore struct
mmc_host is allocated (e.g. dw_mci_probe() and dw_mci_parse_dt() in
dw_mmc.c). Looking at the source of mmc_of_parse_clk_phase(), it's
actually not mandatory to have a initialized mmc_host first, instead we
can pass struct device * to it directly.
Also fix the only current user (sdhci-of-aspeed.c).
Is there a problem? I don't see it, can please elaborate.
My pleasure.
Just look into dw_mci_parse_dt() in dw_mmc.c, this function calls
specific extension's .parse_dt() function. And this function is called
very early even before struct mmc_host is allocated. Thus it'll be
impossible to retrieve host->slot->dev right now since host->slot is
still NULL. As a result, We are unable to call mmc_of_parse_clk_phase()
in our own .parse_dt() because it needs an initialized struct mmc_host.
But mmc_of_parse_clk_phase is intended to be invoked there since this is
where the driver is supposed to parse dt. dw_mci_probe() allocates
struct mmc_host and calls mmc_of_parse() very late(in
dw_mci_init_slot()) and provides us no chance to insert our own dt
parsing extensions after that.
The key is that mmc_of_parse_clk_phase() is a very simple function which
only extracts a few dt props. It is supposed to be called early in the
driver before struct mmc_host is allocated. Unlike mmc_of_parse() which
fills in a lot of fields in struct mmc_host, it does not need this struct.
Kind regards
Uffe
Signed-off-by: Yang Xiwen <forbidden405@xxxxxxxxxxx>
---
drivers/mmc/core/host.c | 4 +---
drivers/mmc/host/sdhci-of-aspeed.c | 2 +-
include/linux/mmc/host.h | 2 +-
3 files changed, 3 insertions(+), 5 deletions(-)
diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index cf396e8f34e9..8b2844ac5dc5 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -234,10 +234,8 @@ static void mmc_of_parse_timing_phase(struct device *dev, const char *prop,
}
void
-mmc_of_parse_clk_phase(struct mmc_host *host, struct mmc_clk_phase_map *map)
+mmc_of_parse_clk_phase(struct device *dev, struct mmc_clk_phase_map *map)
{
- struct device *dev = host->parent;
-
mmc_of_parse_timing_phase(dev, "clk-phase-legacy",
&map->phase[MMC_TIMING_LEGACY]);
mmc_of_parse_timing_phase(dev, "clk-phase-mmc-hs",
diff --git a/drivers/mmc/host/sdhci-of-aspeed.c b/drivers/mmc/host/sdhci-of-aspeed.c
index 42d54532cabe..430c1f90037b 100644
--- a/drivers/mmc/host/sdhci-of-aspeed.c
+++ b/drivers/mmc/host/sdhci-of-aspeed.c
@@ -435,7 +435,7 @@ static int aspeed_sdhci_probe(struct platform_device *pdev)
goto err_sdhci_add;
if (dev->phase_desc)
- mmc_of_parse_clk_phase(host->mmc, &dev->phase_map);
+ mmc_of_parse_clk_phase(&pdev->dev, &dev->phase_map);
ret = sdhci_add_host(host);
if (ret)
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 2f445c651742..5894bf912f7b 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -539,7 +539,7 @@ struct mmc_host *devm_mmc_alloc_host(struct device *dev, int extra);
int mmc_add_host(struct mmc_host *);
void mmc_remove_host(struct mmc_host *);
void mmc_free_host(struct mmc_host *);
-void mmc_of_parse_clk_phase(struct mmc_host *host,
+void mmc_of_parse_clk_phase(struct device *dev,
struct mmc_clk_phase_map *map);
int mmc_of_parse(struct mmc_host *host);
int mmc_of_parse_voltage(struct mmc_host *host, u32 *mask);
---
base-commit: 9d64bf433c53cab2f48a3fff7a1f2a696bc5229a
change-id: 20240215-mmc_phase-26e85511285d
Best regards,
--
Yang Xiwen <forbidden405@xxxxxxxxxxx>
--
Regards,
Yang Xiwen
