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FUI: Fill in link_m and link_n values

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... based on the EDID detailed timing values for
pixel_clock and link_clock.

Two undocumented registers 0x6f040 and 0x6f044 correspond to link_m and link_n
respectively.  Other two undocumented registers 0x6f030 and 0x6f034 correspond
to data_m and data_n respectively.

Calculations are based on the intel_link_compute_m_n from linux kernel.

Currently, the value for 0x6f030 does not come up right with our calculations.
Hence, set to hard-coded value.

Change-Id: I40ff411729d0a61759164c3c1098504973f9cf5e
Reviewed-on: https://gerrit.chromium.org/gerrit/62915
Reviewed-by: Ronald G. Minnich <rminnich@chromium.org>
Tested-by: Furquan Shaikh <furquan@chromium.org>
Commit-Queue: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: http://review.coreboot.org/4381
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>
This commit is contained in:
Furquan Shaikh
2013-07-22 16:18:31 -07:00
committed by Patrick Georgi
parent 3d9b5a2931
commit 6b19071ffb
7 changed files with 98 additions and 27 deletions
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58
src/drivers/intel/gma/intel_dp.c
View File

@ -393,37 +393,51 @@ intel_dp_i2c_init(struct intel_dp *intel_dp)
return ret;
}
struct intel_dp_m_n {
uint32_t tu;
uint32_t gmch_m;
uint32_t gmch_n;
uint32_t link_m;
uint32_t link_n;
};
static void
intel_reduce_ratio(uint32_t *num, uint32_t *den)
intel_reduce_m_n_ratio(uint32_t *num, uint32_t *den)
{
while (*num > 0xffffff || *den > 0xffffff) {
while (*num > DATA_LINK_M_N_MASK || *den > DATA_LINK_M_N_MASK) {
*num >>= 1;
*den >>= 1;
}
}
static void
intel_dp_compute_m_n(int bpp,
int nlanes,
int pixel_clock,
int link_clock,
struct intel_dp_m_n *m_n)
unsigned int roundup_power_of_two(unsigned int n);
unsigned int roundup_power_of_two(unsigned int n)
{
n--;
n |= n >> 1;
n |= n >> 2;
n |= n >> 4;
n |= n >> 8;
n |= n >> 16;
n++;
return n;
}
static void compute_m_n(unsigned int m, unsigned int n,
unsigned int *ret_m, unsigned int *ret_n)
{
*ret_n = MIN(roundup_power_of_two(n), DATA_LINK_N_MAX);
*ret_m = ( (unsigned long long)m * *ret_n) / n;
intel_reduce_m_n_ratio(ret_m, ret_n);
}
void intel_dp_compute_m_n(unsigned int bits_per_pixel,
unsigned int nlanes,
unsigned int pixel_clock,
unsigned int link_clock,
struct intel_dp_m_n *m_n)
{
m_n->tu = 64;
m_n->gmch_m = (pixel_clock * bpp) >> 3;
m_n->gmch_n = link_clock * nlanes;
intel_reduce_ratio(&m_n->gmch_m, &m_n->gmch_n);
m_n->link_m = pixel_clock;
m_n->link_n = link_clock;
intel_reduce_ratio(&m_n->link_m, &m_n->link_n);
compute_m_n(bits_per_pixel * pixel_clock,
link_clock * nlanes * 8,
&m_n->gmch_m, &m_n->gmch_n);
compute_m_n(pixel_clock, link_clock,
&m_n->link_m, &m_n->link_n);
}
/* not sure. */