Re: [PATCH V2 03/27] mmc: mmci: convert dma_setup callback to return an int
From: Ludovic BARRE
Date: Mon Sep 24 2018 - 12:14:35 EST
hi Ulf
On 09/24/2018 04:28 PM, Ulf Hansson wrote:
On 21 September 2018 at 11:45, Ludovic Barre <ludovic.Barre@xxxxxx> wrote:
From: Ludovic Barre <ludovic.barre@xxxxxx>
This patch converts dma_setup callback to return an integer
This patch is needed to prepare sdmmc variant with internal dma
Signed-off-by: Ludovic Barre <ludovic.barre@xxxxxx>
---
drivers/mmc/host/mmci.c | 14 ++++++++++----
drivers/mmc/host/mmci.h | 2 +-
drivers/mmc/host/mmci_qcom_dml.c | 6 ++++--
3 files changed, 15 insertions(+), 7 deletions(-)
diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index cbd67bc..2f845f3 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -415,7 +415,7 @@ static void mmci_init_sg(struct mmci_host *host, struct mmc_data *data)
* no custom DMA interfaces are supported.
*/
#ifdef CONFIG_DMA_ENGINE
-static void mmci_dma_setup(struct mmci_host *host)
+static int mmci_dma_setup(struct mmci_host *host)
{
const char *rxname, *txname;
@@ -466,7 +466,9 @@ static void mmci_dma_setup(struct mmci_host *host)
}
if (host->ops && host->ops->dma_setup)
- host->ops->dma_setup(host);
+ return host->ops->dma_setup(host);
+
Looks like you need to implement a error handling, instead of just
returning the error code.
yes, today if a dma_setup is defined, we can't fallback to pio mode.
A use_dma variable (defined in mmci_host) could be setted follow the
return code of ops->dma_setup
example:
void mmci_dma_setup(struct mmci_host *host)
{
int err;
if (!host->ops || !host->ops->dma_setup)
return;
err = host->ops->dma_setup(host);
if (err)
return;
host->use_dma = true;
/* initialize pre request cookie */
host->next_cookie = 1;
}
use_dma variable could be check by mmci_host_ops variant functions.
are you agree with this proposal?
+ return 0;
}
/*
@@ -741,8 +743,10 @@ static void mmci_post_request(struct mmc_host *mmc, struct mmc_request *mrq,
static void mmci_get_next_data(struct mmci_host *host, struct mmc_data *data)
{
}
-static inline void mmci_dma_setup(struct mmci_host *host)
+
+static inline int mmci_dma_setup(struct mmci_host *host)
{
+ return 0;
}
static inline void mmci_dma_release(struct mmci_host *host)
@@ -1796,7 +1800,9 @@ static int mmci_probe(struct amba_device *dev,
amba_rev(dev), (unsigned long long)dev->res.start,
dev->irq[0], dev->irq[1]);
- mmci_dma_setup(host);
+ ret = mmci_dma_setup(host);
+ if (ret)
+ goto clk_disable;
pm_runtime_set_autosuspend_delay(&dev->dev, 50);
pm_runtime_use_autosuspend(&dev->dev);
diff --git a/drivers/mmc/host/mmci.h b/drivers/mmc/host/mmci.h
index 21aaf9a..06299ac 100644
--- a/drivers/mmc/host/mmci.h
+++ b/drivers/mmc/host/mmci.h
@@ -273,7 +273,7 @@ struct variant_data {
/* mmci variant callbacks */
struct mmci_host_ops {
- void (*dma_setup)(struct mmci_host *host);
+ int (*dma_setup)(struct mmci_host *host);
};
struct mmci_host_next {
diff --git a/drivers/mmc/host/mmci_qcom_dml.c b/drivers/mmc/host/mmci_qcom_dml.c
index be3fab5..1bb59cf 100644
--- a/drivers/mmc/host/mmci_qcom_dml.c
+++ b/drivers/mmc/host/mmci_qcom_dml.c
@@ -119,7 +119,7 @@ static int of_get_dml_pipe_index(struct device_node *np, const char *name)
}
/* Initialize the dml hardware connected to SD Card controller */
-static void qcom_dma_setup(struct mmci_host *host)
+static int qcom_dma_setup(struct mmci_host *host)
{
u32 config;
void __iomem *base;
@@ -131,7 +131,7 @@ static void qcom_dma_setup(struct mmci_host *host)
if (producer_id < 0 || consumer_id < 0) {
host->variant->qcom_dml = false;
It seems like the existing code is an attempt to fallback to use pio
mode. However, I doubt it works as is.
oops, I seen that like a variant identification issue, so if it's a
fallback to pio mode it doesn't work.
- return;
+ return -EINVAL;
My point is, if you return an error code here, it means that the error
code becomes propagated and ->probe() will fail.
Ideally, we should be able fall back to pio mode when dma doesn't
work. I have looped in Srinivas who implemented the qcom dml support,
let's see if he can explains the intent with the code.
I also volunteer to help out running some tests on the 410c platform,
however allow me a day or two to do that.
yes, I would be more reassured
}
base = host->base + DML_OFFSET;
@@ -175,6 +175,8 @@ static void qcom_dma_setup(struct mmci_host *host)
/* Make sure dml initialization is finished */
mb();
+
+ return 0;
}
static struct mmci_host_ops qcom_variant_ops = {
--
2.7.4
Kind regards
Uffe