| Message ID | 20230929-mmc-caps-v2-2-11a4c2d94f15@axis.com |
|---|---|
| State | New |
| Headers | show |
| Series | mmc: Allow speed modes to be adjusted dynamically | expand |
On Fri, 29 Sept 2023 at 21:17, Vincent Whitchurch <vincent.whitchurch@axis.com> wrote: > > During board verification, there is a need to test the various supported > eMMC/SD speed modes. However, since the framework chooses the best mode > supported by the card and the host controller's caps, this currently > necessitates changing the devicetree for every iteration. > > Allow the various speed mode host capabilities to be modified via > debugfs in order to allow easier hardware verification. The values to > be written are the raw MMC_CAP* values from include/linux/mmc/host.h. > This is rather low-level, and these defines are not guaranteed to be > stable, but it is perhaps good enough for the intended use case. > > MMC_CAP_AGGRESSIVE_PM can also be set, in order to be able to > re-initialize the card without having to physically remove and re-insert > it. > > /sys/kernel/debug/mmc0# grep timing ios > timing spec: 9 (mmc HS200) > > // Turn on MMC_CAP_AGGRESSIVE_PM and re-trigger runtime suspend > /sys/kernel/debug/mmc0# echo $(($(cat caps) | (1 << 7))) > caps > /sys/kernel/debug/mmc0# echo on > /sys/bus/mmc/devices/mmc0\:0001/power/control > /sys/kernel/debug/mmc0# echo auto > /sys/bus/mmc/devices/mmc0\:0001/power/control > > // MMC_CAP2_HS200_1_8V_SDR > /sys/kernel/debug/mmc0# echo $(($(cat caps2) & ~(1 << 5))) > caps2 $(($(cat caps2) & ~(1 << 5))) looks complicated, does it use echo DDR52 > caps2? > /sys/kernel/debug/mmc0# echo on > /sys/bus/mmc/devices/mmc0\:0001/power/control > /sys/kernel/debug/mmc0# grep timing ios > timing spec: 8 (mmc DDR52) > > Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com> > --- > drivers/mmc/core/debugfs.c | 51 ++++++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 49 insertions(+), 2 deletions(-) > > diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c > index 2c97b94aab23..1642ea72d22c 100644 > --- a/drivers/mmc/core/debugfs.c > +++ b/drivers/mmc/core/debugfs.c > @@ -12,9 +12,12 @@ > #include <linux/slab.h> > #include <linux/stat.h> > #include <linux/fault-inject.h> > +#include <linux/time.h> > > #include <linux/mmc/card.h> > #include <linux/mmc/host.h> > +#include <linux/mmc/mmc.h> > +#include <linux/mmc/sd.h> > > #include "core.h" > #include "card.h" > @@ -298,6 +301,49 @@ static const struct file_operations mmc_err_stats_fops = { > .release = single_release, > }; > > +static int mmc_caps_get(void *data, u64 *val) > +{ > + *val = *(u32 *)data; > + return 0; > +} > + > +static int mmc_caps_set(void *data, u64 val) > +{ > + u32 *caps = data; > + u32 diff = *caps ^ val; > + u32 allowed = MMC_CAP_AGGRESSIVE_PM | > + MMC_CAP_SD_HIGHSPEED | > + MMC_CAP_MMC_HIGHSPEED | > + MMC_CAP_UHS | > + MMC_CAP_DDR; > + > + if (diff & ~allowed) > + return -EINVAL; > + > + *caps = val; > + > + return 0; > +} > + > +static int mmc_caps2_set(void *data, u64 val) > +{ > + u32 allowed = MMC_CAP2_HSX00_1_8V | MMC_CAP2_HSX00_1_2V; > + u32 *caps = data; > + u32 diff = *caps ^ val; > + > + if (diff & ~allowed) > + return -EINVAL; > + > + *caps = val; > + > + return 0; > +} > + > +DEFINE_DEBUGFS_ATTRIBUTE(mmc_caps_fops, mmc_caps_get, mmc_caps_set, > + "0x%08llx\n"); > +DEFINE_DEBUGFS_ATTRIBUTE(mmc_caps2_fops, mmc_caps_get, mmc_caps2_set, > + "0x%08llx\n"); > + > void mmc_add_host_debugfs(struct mmc_host *host) > { > struct dentry *root; > @@ -306,8 +352,9 @@ void mmc_add_host_debugfs(struct mmc_host *host) > host->debugfs_root = root; > > debugfs_create_file("ios", S_IRUSR, root, host, &mmc_ios_fops); > - debugfs_create_x32("caps", S_IRUSR, root, &host->caps); > - debugfs_create_x32("caps2", S_IRUSR, root, &host->caps2); > + debugfs_create_file("caps", 0600, root, &host->caps, &mmc_caps_fops); > + debugfs_create_file("caps2", 0600, root, &host->caps2, > + &mmc_caps2_fops); Would it be better to use "S_IRUSR | S_IWUSR" instead of "0600"? > debugfs_create_file_unsafe("clock", S_IRUSR | S_IWUSR, root, host, > &mmc_clock_fops); > > > -- > 2.34.1 >
On Sat, 2023-10-07 at 10:27 +0800, Wenchao Chen wrote: > On Fri, 29 Sept 2023 at 21:17, Vincent Whitchurch > <vincent.whitchurch@axis.com> wrote: > > // MMC_CAP2_HS200_1_8V_SDR > > /sys/kernel/debug/mmc0# echo $(($(cat caps2) & ~(1 << 5))) > caps2 > > $(($(cat caps2) & ~(1 << 5))) looks complicated, does it use echo DDR52 > caps2? 1 << 5 is (as the comment above says) MMC_CAP2_HS200_1_8V_SDR. The read-modify-write is needed to not clear unrelated bits. The MMC framework picks the best possible mode supported by both the card and the host controller, so disabling support for HS200 in the host controller leads to DDR52 being picked in this case. [...] > > void mmc_add_host_debugfs(struct mmc_host *host) > > { > > struct dentry *root; > > @@ -306,8 +352,9 @@ void mmc_add_host_debugfs(struct mmc_host *host) > > host->debugfs_root = root; > > > > debugfs_create_file("ios", S_IRUSR, root, host, &mmc_ios_fops); > > - debugfs_create_x32("caps", S_IRUSR, root, &host->caps); > > - debugfs_create_x32("caps2", S_IRUSR, root, &host->caps2); > > + debugfs_create_file("caps", 0600, root, &host->caps, &mmc_caps_fops); > > + debugfs_create_file("caps2", 0600, root, &host->caps2, > > + &mmc_caps2_fops); > > Would it be better to use "S_IRUSR | S_IWUSR" instead of "0600"? No, not according to checkpatch which says that numeric permissions are preferred.
diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c index 2c97b94aab23..1642ea72d22c 100644 --- a/drivers/mmc/core/debugfs.c +++ b/drivers/mmc/core/debugfs.c @@ -12,9 +12,12 @@ #include <linux/slab.h> #include <linux/stat.h> #include <linux/fault-inject.h> +#include <linux/time.h> #include <linux/mmc/card.h> #include <linux/mmc/host.h> +#include <linux/mmc/mmc.h> +#include <linux/mmc/sd.h> #include "core.h" #include "card.h" @@ -298,6 +301,49 @@ static const struct file_operations mmc_err_stats_fops = { .release = single_release, }; +static int mmc_caps_get(void *data, u64 *val) +{ + *val = *(u32 *)data; + return 0; +} + +static int mmc_caps_set(void *data, u64 val) +{ + u32 *caps = data; + u32 diff = *caps ^ val; + u32 allowed = MMC_CAP_AGGRESSIVE_PM | + MMC_CAP_SD_HIGHSPEED | + MMC_CAP_MMC_HIGHSPEED | + MMC_CAP_UHS | + MMC_CAP_DDR; + + if (diff & ~allowed) + return -EINVAL; + + *caps = val; + + return 0; +} + +static int mmc_caps2_set(void *data, u64 val) +{ + u32 allowed = MMC_CAP2_HSX00_1_8V | MMC_CAP2_HSX00_1_2V; + u32 *caps = data; + u32 diff = *caps ^ val; + + if (diff & ~allowed) + return -EINVAL; + + *caps = val; + + return 0; +} + +DEFINE_DEBUGFS_ATTRIBUTE(mmc_caps_fops, mmc_caps_get, mmc_caps_set, + "0x%08llx\n"); +DEFINE_DEBUGFS_ATTRIBUTE(mmc_caps2_fops, mmc_caps_get, mmc_caps2_set, + "0x%08llx\n"); + void mmc_add_host_debugfs(struct mmc_host *host) { struct dentry *root; @@ -306,8 +352,9 @@ void mmc_add_host_debugfs(struct mmc_host *host) host->debugfs_root = root; debugfs_create_file("ios", S_IRUSR, root, host, &mmc_ios_fops); - debugfs_create_x32("caps", S_IRUSR, root, &host->caps); - debugfs_create_x32("caps2", S_IRUSR, root, &host->caps2); + debugfs_create_file("caps", 0600, root, &host->caps, &mmc_caps_fops); + debugfs_create_file("caps2", 0600, root, &host->caps2, + &mmc_caps2_fops); debugfs_create_file_unsafe("clock", S_IRUSR | S_IWUSR, root, host, &mmc_clock_fops);
During board verification, there is a need to test the various supported eMMC/SD speed modes. However, since the framework chooses the best mode supported by the card and the host controller's caps, this currently necessitates changing the devicetree for every iteration. Allow the various speed mode host capabilities to be modified via debugfs in order to allow easier hardware verification. The values to be written are the raw MMC_CAP* values from include/linux/mmc/host.h. This is rather low-level, and these defines are not guaranteed to be stable, but it is perhaps good enough for the intended use case. MMC_CAP_AGGRESSIVE_PM can also be set, in order to be able to re-initialize the card without having to physically remove and re-insert it. /sys/kernel/debug/mmc0# grep timing ios timing spec: 9 (mmc HS200) // Turn on MMC_CAP_AGGRESSIVE_PM and re-trigger runtime suspend /sys/kernel/debug/mmc0# echo $(($(cat caps) | (1 << 7))) > caps /sys/kernel/debug/mmc0# echo on > /sys/bus/mmc/devices/mmc0\:0001/power/control /sys/kernel/debug/mmc0# echo auto > /sys/bus/mmc/devices/mmc0\:0001/power/control // MMC_CAP2_HS200_1_8V_SDR /sys/kernel/debug/mmc0# echo $(($(cat caps2) & ~(1 << 5))) > caps2 /sys/kernel/debug/mmc0# echo on > /sys/bus/mmc/devices/mmc0\:0001/power/control /sys/kernel/debug/mmc0# grep timing ios timing spec: 8 (mmc DDR52) Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com> --- drivers/mmc/core/debugfs.c | 51 ++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 49 insertions(+), 2 deletions(-)