[PATCH] drm/amd/amdgpu: New debugfs interface for MMIO registers (v2)
Tom St Denis
tstdenis82 at gmail.com
Wed Aug 25 11:04:37 UTC 2021
I tested it by forcing bit patterns into the ioctl data and printing it out
in the kernel log. I'm not siloed into it one way or the other. I'll just
change it to u32.
On Wed, Aug 25, 2021 at 7:03 AM Christian König <
ckoenig.leichtzumerken at gmail.com> wrote:
> Using u8 is ok as well, just make sure that you don't have any hidden
> padding.
>
> Nirmoy had a tool to double check for paddings which I once more forgot
> the name of.
>
> Christian.
>
> Am 25.08.21 um 12:40 schrieb Tom St Denis:
>
> The struct works as is but I'll change them to u32. The offset is an
> artefact of the fact this was an IOCTL originally. I'm working both ends
> in parallel trying to make the changes at the same time because I'm only
> submitting the kernel patch if I've tested it in userspace.
>
> I'll send a v4 in a bit this morning....
>
> Tom
>
> On Wed, Aug 25, 2021 at 2:35 AM Christian König <
> ckoenig.leichtzumerken at gmail.com> wrote:
>
>>
>>
>> Am 24.08.21 um 15:36 schrieb Tom St Denis:
>> > This new debugfs interface uses an IOCTL interface in order to pass
>> > along state information like SRBM and GRBM bank switching. This
>> > new interface also allows a full 32-bit MMIO address range which
>> > the previous didn't. With this new design we have room to grow
>> > the flexibility of the file as need be.
>> >
>> > (v2): Move read/write to .read/.write, fix style, add comment
>> > for IOCTL data structure
>> >
>> > Signed-off-by: Tom St Denis <tom.stdenis at amd.com>
>> > ---
>> > drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c | 162 ++++++++++++++++++++
>> > drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.h | 32 ++++
>> > 2 files changed, 194 insertions(+)
>> >
>> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
>> > index 277128846dd1..8e8f5743c8f5 100644
>> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
>> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
>> > @@ -279,6 +279,156 @@ static ssize_t amdgpu_debugfs_regs_write(struct
>> file *f, const char __user *buf,
>> > return amdgpu_debugfs_process_reg_op(false, f, (char __user
>> *)buf, size, pos);
>> > }
>> >
>> > +static int amdgpu_debugfs_regs2_open(struct inode *inode, struct file
>> *file)
>> > +{
>> > + struct amdgpu_debugfs_regs2_data *rd;
>> > +
>> > + rd = kzalloc(sizeof *rd, GFP_KERNEL);
>> > + if (!rd)
>> > + return -ENOMEM;
>> > + rd->adev = file_inode(file)->i_private;
>> > + file->private_data = rd;
>> > +
>> > + return 0;
>> > +}
>> > +
>> > +static int amdgpu_debugfs_regs2_release(struct inode *inode, struct
>> file *file)
>> > +{
>> > + kfree(file->private_data);
>> > + return 0;
>> > +}
>> > +
>> > +static ssize_t amdgpu_debugfs_regs2_op(struct file *f, char __user
>> *buf, size_t size, int write_en)
>> > +{
>> > + struct amdgpu_debugfs_regs2_data *rd = f->private_data;
>> > + struct amdgpu_device *adev = rd->adev;
>> > + ssize_t result = 0;
>> > + int r;
>> > + uint32_t value;
>> > +
>> > + if (size & 0x3 || rd->state.offset & 0x3)
>> > + return -EINVAL;
>> > +
>> > + if (rd->state.id.use_grbm) {
>> > + if (rd->state.id.grbm.se == 0x3FF)
>> > + rd->state.id.grbm.se = 0xFFFFFFFF;
>> > + if (rd->state.id.grbm.sh == 0x3FF)
>> > + rd->state.id.grbm.sh = 0xFFFFFFFF;
>> > + if (rd->state.id.grbm.instance == 0x3FF)
>> > + rd->state.id.grbm.instance = 0xFFFFFFFF;
>> > + }
>> > +
>> > + r = pm_runtime_get_sync(adev_to_drm(adev)->dev);
>> > + if (r < 0) {
>> > + pm_runtime_put_autosuspend(adev_to_drm(adev)->dev);
>> > + return r;
>> > + }
>> > +
>> > + r = amdgpu_virt_enable_access_debugfs(adev);
>> > + if (r < 0) {
>> > + pm_runtime_put_autosuspend(adev_to_drm(adev)->dev);
>> > + return r;
>> > + }
>> > +
>> > + if (rd->state.id.use_grbm) {
>> > + if ((rd->state.id.grbm.sh != 0xFFFFFFFF && rd->
>> state.id.grbm.sh >= adev->gfx.config.max_sh_per_se) ||
>> > + (rd->state.id.grbm.se != 0xFFFFFFFF && rd->
>> state.id.grbm.se >= adev->gfx.config.max_shader_engines)) {
>> > + pm_runtime_mark_last_busy(adev_to_drm(adev)->dev);
>> > +
>> pm_runtime_put_autosuspend(adev_to_drm(adev)->dev);
>> > + amdgpu_virt_disable_access_debugfs(adev);
>> > + return -EINVAL;
>> > + }
>> > + mutex_lock(&adev->grbm_idx_mutex);
>> > + amdgpu_gfx_select_se_sh(adev, rd->state.id.grbm.se,
>> > + rd->
>> state.id.grbm.sh,
>> > +
>> rd->state.id.grbm.instance);
>> > + }
>> > +
>> > + if (rd->state.id.use_srbm) {
>> > + mutex_lock(&adev->srbm_mutex);
>> > + amdgpu_gfx_select_me_pipe_q(adev, rd->state.id.srbm.me,
>> rd->state.id.srbm.pipe,
>> > +
>> rd->state.id.srbm.queue, rd->state.id.srbm.vmid);
>> > + }
>> > +
>> > + if (rd->state.id.pg_lock)
>> > + mutex_lock(&adev->pm.mutex);
>> > +
>> > + while (size) {
>> > + if (!write_en) {
>> > + value = RREG32(rd->state.offset >> 2);
>> > + r = put_user(value, (uint32_t *)buf);
>> > + } else {
>> > + r = get_user(value, (uint32_t *)buf);
>> > + if (!r)
>> > + amdgpu_mm_wreg_mmio_rlc(adev,
>> rd->state.offset >> 2, value);
>> > + }
>> > + if (r) {
>> > + result = r;
>> > + goto end;
>> > + }
>> > + rd->state.offset += 4;
>> > + size -= 4;
>> > + result += 4;
>> > + buf += 4;
>> > + }
>> > +end:
>> > + if (rd->state.id.use_grbm) {
>> > + amdgpu_gfx_select_se_sh(adev, 0xffffffff, 0xffffffff,
>> 0xffffffff);
>> > + mutex_unlock(&adev->grbm_idx_mutex);
>> > + }
>> > +
>> > + if (rd->state.id.use_srbm) {
>> > + amdgpu_gfx_select_me_pipe_q(adev, 0, 0, 0, 0);
>> > + mutex_unlock(&adev->srbm_mutex);
>> > + }
>> > +
>> > + if (rd->state.id.pg_lock)
>> > + mutex_unlock(&adev->pm.mutex);
>> > +
>> > + // in umr (the likely user of this) flags are set per file
>> operation
>> > + // which means they're never "unset" explicitly. To avoid
>> breaking
>> > + // this convention we unset the flags after each operation
>> > + // flags are for a single call (need to be set for every
>> read/write)
>> > + rd->state.id.use_grbm = 0;
>> > + rd->state.id.use_srbm = 0;
>> > + rd->state.id.pg_lock = 0;
>> > +
>> > + pm_runtime_mark_last_busy(adev_to_drm(adev)->dev);
>> > + pm_runtime_put_autosuspend(adev_to_drm(adev)->dev);
>> > +
>> > + amdgpu_virt_disable_access_debugfs(adev);
>> > + return result;
>> > +}
>> > +
>> > +static long amdgpu_debugfs_regs2_ioctl(struct file *f, unsigned int
>> cmd, unsigned long data)
>> > +{
>> > + struct amdgpu_debugfs_regs2_data *rd = f->private_data;
>> > +
>> > + switch (cmd) {
>> > + case AMDGPU_DEBUGFS_REGS2_IOC_SET_STATE:
>> > + if (copy_from_user(&rd->state.id, (struct
>> amdgpu_debugfs_regs2_iocdata *)data, sizeof rd->state.id))
>> > + return -EINVAL;
>> > + break;
>> > + default:
>> > + return -EINVAL;
>> > + }
>> > + return 0;
>> > +}
>> > +
>> > +static ssize_t amdgpu_debugfs_regs2_read(struct file *f, char __user
>> *buf, size_t size, loff_t *pos)
>> > +{
>> > + struct amdgpu_debugfs_regs2_data *rd = f->private_data;
>> > + rd->state.offset = *pos;
>> > + return amdgpu_debugfs_regs2_op(f, buf, size, 0);
>> > +}
>> > +
>> > +static ssize_t amdgpu_debugfs_regs2_write(struct file *f, const char
>> __user *buf, size_t size, loff_t *pos)
>> > +{
>> > + struct amdgpu_debugfs_regs2_data *rd = f->private_data;
>> > + rd->state.offset = *pos;
>> > + return amdgpu_debugfs_regs2_op(f, (char __user *)buf, size, 1);
>> > +}
>> > +
>> >
>> > /**
>> > * amdgpu_debugfs_regs_pcie_read - Read from a PCIE register
>> > @@ -1091,6 +1241,16 @@ static ssize_t amdgpu_debugfs_gfxoff_read(struct
>> file *f, char __user *buf,
>> > return result;
>> > }
>> >
>> > +static const struct file_operations amdgpu_debugfs_regs2_fops = {
>> > + .owner = THIS_MODULE,
>> > + .unlocked_ioctl = amdgpu_debugfs_regs2_ioctl,
>> > + .read = amdgpu_debugfs_regs2_read,
>> > + .write = amdgpu_debugfs_regs2_write,
>> > + .open = amdgpu_debugfs_regs2_open,
>> > + .release = amdgpu_debugfs_regs2_release,
>> > + .llseek = default_llseek
>> > +};
>> > +
>> > static const struct file_operations amdgpu_debugfs_regs_fops = {
>> > .owner = THIS_MODULE,
>> > .read = amdgpu_debugfs_regs_read,
>> > @@ -1148,6 +1308,7 @@ static const struct file_operations
>> amdgpu_debugfs_gfxoff_fops = {
>> >
>> > static const struct file_operations *debugfs_regs[] = {
>> > &amdgpu_debugfs_regs_fops,
>> > + &amdgpu_debugfs_regs2_fops,
>> > &amdgpu_debugfs_regs_didt_fops,
>> > &amdgpu_debugfs_regs_pcie_fops,
>> > &amdgpu_debugfs_regs_smc_fops,
>> > @@ -1160,6 +1321,7 @@ static const struct file_operations
>> *debugfs_regs[] = {
>> >
>> > static const char *debugfs_regs_names[] = {
>> > "amdgpu_regs",
>> > + "amdgpu_regs2",
>> > "amdgpu_regs_didt",
>> > "amdgpu_regs_pcie",
>> > "amdgpu_regs_smc",
>> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.h
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.h
>> > index 141a8474e24f..ec044df5d428 100644
>> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.h
>> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.h
>> > @@ -22,6 +22,8 @@
>> > * OTHER DEALINGS IN THE SOFTWARE.
>> > *
>> > */
>> > +#include <linux/ioctl.h>
>> > +#include <uapi/drm/amdgpu_drm.h>
>> >
>> > /*
>> > * Debugfs
>> > @@ -38,3 +40,33 @@ void amdgpu_debugfs_fence_init(struct amdgpu_device
>> *adev);
>> > void amdgpu_debugfs_firmware_init(struct amdgpu_device *adev);
>> > void amdgpu_debugfs_gem_init(struct amdgpu_device *adev);
>> > int amdgpu_debugfs_wait_dump(struct amdgpu_device *adev);
>> > +
>> > +/*
>> > + * MMIO debugfs IOCTL structure
>> > + */
>> > +struct amdgpu_debugfs_regs2_iocdata {
>> > + __u8 use_srbm, use_grbm, pg_lock;
>>
>> You should consider using u32 here as well or add explicitly padding.
>>
>> > + struct {
>> > + __u32 se, sh, instance;
>> > + } grbm;
>> > + struct {
>> > + __u32 me, pipe, queue, vmid;
>> > + } srbm;
>> > +};
>> > +
>> > +/*
>> > + * MMIO debugfs state data (per file* handle)
>> > + */
>> > +struct amdgpu_debugfs_regs2_data {
>> > + struct amdgpu_device *adev;
>> > + struct {
>> > + struct amdgpu_debugfs_regs2_iocdata id;
>> > + __u32 offset;
>>
>> What is the offset good for here?
>>
>> Regards,
>> Christian.
>>
>> > + } state;
>> > +};
>> > +
>> > +enum AMDGPU_DEBUGFS_REGS2_CMDS {
>> > + AMDGPU_DEBUGFS_REGS2_CMD_SET_STATE=0,
>> > +};
>> > +
>> > +#define AMDGPU_DEBUGFS_REGS2_IOC_SET_STATE _IOWR(0x20,
>> AMDGPU_DEBUGFS_REGS2_CMD_SET_STATE, struct amdgpu_debugfs_regs2_iocdata)
>>
>>
>
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