[PATCH 8/8 v2] ARM OMAP2+ GPMC: fix WAITMONITORINGTIME divider bug

Robert ABEL
2015-02-24T20:05:51Z

The WAITMONITORINGTIME is expressed as a number of GPMC_CLK clock cycles,
even though the access is defined as asynchronous, and no GPMC_CLK clock
is provided to the external device. Still, GPMCFCLKDIVIDER is used as a divider
for the GPMC clock, so it must be programmed to define the
correct WAITMONITORINGTIME delay.

This patch correctly computes WAITMONITORINGTIME in GPMC_CLK cycles instead of GPMC_FCLK cycles,
both during programming (gpmc_cs_set_timings) and during retrieval (gpmc_cs_show_timings).

Signed-off-by: Robert ABEL <rabel@cit-ec.uni-bielefeld.de>
---
drivers/memory/omap-gpmc.c | 125 +++++++++++++++++++++++++++++++++++----------
1 file changed, 99 insertions(+), 26 deletions(-)

diff --git a/drivers/memory/omap-gpmc.c b/drivers/memory/omap-gpmc.c
index 9cf8d21..6591991 100644
--- a/drivers/memory/omap-gpmc.c
+++ b/drivers/memory/omap-gpmc.c
@@ -170,6 +170,11 @@
*/
#define GPMC_NR_IRQ 2

+enum gpmc_clk_domain {
+ GPMC_CD_FCLK,
+ GPMC_CD_CLK
+};
+
struct gpmc_cs_data {
const char *name;

@@ -268,16 +273,55 @@ static unsigned long gpmc_get_fclk_period(void)
return rate;
}

-static unsigned int gpmc_ns_to_ticks(unsigned int time_ns)
+/**
+ * gpmc_get_clk_period - get period of selected clock domain in ps
+ * @cs Chip Select Region.
+ * @cd Clock Domain.
+ *
+ * GPMC_CS_CONFIG1 GPMCFCLKDIVIDER for cs has to be setup
+ * prior to calling this function with GPMC_CD_CLK.
+ *
+ */
+static unsigned long gpmc_get_clk_period(int cs, enum gpmc_clk_domain cd)
+{
+
+ unsigned long tick_ps = gpmc_get_fclk_period();
+ u32 l;
+ int div;
+
+ switch (cd) {
+ case GPMC_CD_CLK:
+ /* get current clk divider */
+ l = gpmc_cs_read_reg(cs, GPMC_CS_CONFIG1);
+ div = (l & 0x03) + 1;
+ /* get GPMC_CLK period */
+ tick_ps *= div;
+ break;
+ case GPMC_CD_FCLK:
+ /* FALL-THROUGH */
+ default:
+ break;
+ }
+
+ return tick_ps;
+
+}
+
+static unsigned int gpmc_ns_to_clk_ticks(unsigned int time_ns, int cs, enum gpmc_clk_domain cd)
{
unsigned long tick_ps;

/* Calculate in picosecs to yield more exact results */
- tick_ps = gpmc_get_fclk_period();
+ tick_ps = gpmc_get_clk_period(cs, cd);

return (time_ns * 1000 + tick_ps - 1) / tick_ps;
}

+static unsigned int gpmc_ns_to_ticks(unsigned int time_ns)
+{
+ return gpmc_ns_to_clk_ticks(time_ns, /* any CS */ 0, GPMC_CD_FCLK);
+}
+
static unsigned int gpmc_ps_to_ticks(unsigned int time_ps)
{
unsigned long tick_ps;
@@ -288,9 +332,14 @@ static unsigned int gpmc_ps_to_ticks(unsigned int time_ps)
return (time_ps + tick_ps - 1) / tick_ps;
}

+unsigned int gpmc_clk_ticks_to_ns(unsigned ticks, int cs, enum gpmc_clk_domain cd)
+{
+ return ticks * gpmc_get_clk_period(cs, cd) / 1000;
+}
+
unsigned int gpmc_ticks_to_ns(unsigned int ticks)
{
- return ticks * gpmc_get_fclk_period() / 1000;
+ return gpmc_clk_ticks_to_ns(ticks, /* any CS */ 0, GPMC_CD_FCLK);
}

static unsigned int gpmc_ticks_to_ps(unsigned int ticks)
@@ -346,16 +395,22 @@ static void gpmc_cs_bool_timings(int cs, const struct gpmc_bool_timings *p)
* @st_bit Start Bit
* @end_bit End Bit. Must be >= @st_bit.
* @name DTS node name, w/o "gpmc,"
+ * @cd Clock Domain of timing parameter.
+ * @shift Parameter value left shifts @shift, which is then printed instead of value.
* @raw Raw Format Option.
* raw format: gpmc,name = <value>
* tick format: gpmc,name = <value> /&zwj;* x ticks *&zwj;/
* @noval Parameter values equal to 0 are not printed.
- * @shift Parameter value left shifts @shift, which is then printed instead of value.
*
*/
-static int get_gpmc_timing_reg(int cs, int reg, int st_bit, int end_bit,
- bool raw, bool noval, int shift,
- const char *name)
+static int get_gpmc_timing_reg(
+ /* timing specifiers */
+ int cs, int reg, int st_bit, int end_bit,
+ const char *name, const enum gpmc_clk_domain cd,
+ /* value transform */
+ int shift,
+ /* format specifiers */
+ bool raw, bool noval)
{
u32 l;
int nr_bits;
@@ -373,7 +428,7 @@ static int get_gpmc_timing_reg(int cs, int reg, int st_bit, int end_bit,
/* DTS tick format for timings in ns */
unsigned int time_ns;

- time_ns = gpmc_ticks_to_ns(l);
+ time_ns = gpmc_clk_ticks_to_ns(l, cs, cd);
pr_info("gpmc,%s = <%u> /* %i ticks */\n",
name, time_ns, l);
} else {
@@ -388,13 +443,15 @@ static int get_gpmc_timing_reg(int cs, int reg, int st_bit, int end_bit,
pr_info("cs%i %s: 0x%08x\n", cs, #config, \
gpmc_cs_read_reg(cs, config))
#define GPMC_GET_RAW(reg, st, end, field) \
- get_gpmc_timing_reg(cs, (reg), (st), (end), 1, 0, 0, field)
+ get_gpmc_timing_reg(cs, (reg), (st), (end), field, GPMC_CD_FCLK, 0, 1, 0)
#define GPMC_GET_RAW_BOOL(reg, st, end, field) \
- get_gpmc_timing_reg(cs, (reg), (st), (end), 1, 1, 0, field)
+ get_gpmc_timing_reg(cs, (reg), (st), (end), field, GPMC_CD_FCLK, 0, 1, 1)
#define GPMC_GET_RAW_SHIFT(reg, st, end, shift, field) \
- get_gpmc_timing_reg(cs, (reg), (st), (end), 1, 1, (shift), field)
+ get_gpmc_timing_reg(cs, (reg), (st), (end), field, GPMC_CD_FCLK, (shift), 1, 1)
#define GPMC_GET_TICKS(reg, st, end, field) \
- get_gpmc_timing_reg(cs, (reg), (st), (end), 0, 0, 0, field)
+ get_gpmc_timing_reg(cs, (reg), (st), (end), field, GPMC_CD_FCLK, 0, 0, 0)
+#define GPMC_GET_TICKS_CD(reg, st, end, field, cd) \
+ get_gpmc_timing_reg(cs, (reg), (st), (end), field, (cd), 0, 0, 0)

static void gpmc_show_regs(int cs, const char *desc)
{
@@ -462,7 +519,7 @@ static void gpmc_cs_show_timings(int cs, const char *desc)
GPMC_GET_TICKS(GPMC_CS_CONFIG6, 0, 3, "bus-turnaround-ns");
GPMC_GET_TICKS(GPMC_CS_CONFIG6, 8, 11, "cycle2cycle-delay-ns");

- GPMC_GET_TICKS(GPMC_CS_CONFIG1, 18, 19, "wait-monitoring-ns");
+ GPMC_GET_TICKS_CD(GPMC_CS_CONFIG1, 18, 19, "wait-monitoring-ns", GPMC_CD_CLK);
GPMC_GET_TICKS(GPMC_CS_CONFIG1, 25, 26, "clk-activation-ns");

GPMC_GET_TICKS(GPMC_CS_CONFIG6, 16, 19, "wr-data-mux-bus-ns");
@@ -474,8 +531,20 @@ static inline void gpmc_cs_show_timings(int cs, const char *desc)
}
#endif

+/**
+ * set_gpmc_timing_reg - set a single timing parameter for Chip Select Region.
+ * @cs Chip Select Region.
+ * @reg GPMC_CS_CONFIGn register offset.
+ * @st_bit Start Bit
+ * @end_bit End Bit. Must be >= @st_bit.
+ * @time Timing parameter in ns.
+ * @cd Timing parameter clock domain.
+ * @name Timing parameter name.
+ * @note Caller is expected to have initialized CONFIG1 GPMCFCLKDIVIDER
+ * prior to calling this function with @cd equal to GPMC_CD_CLK.
+ */
static int set_gpmc_timing_reg(int cs, int reg, int st_bit, int end_bit,
- int time, const char *name)
+ int time, enum gpmc_clk_domain cd, const char *name)
{
u32 l;
int ticks, mask, nr_bits;
@@ -483,12 +552,12 @@ static int set_gpmc_timing_reg(int cs, int reg, int st_bit, int end_bit,
if (time == 0)
ticks = 0;
else
- ticks = gpmc_ns_to_ticks(time);
+ ticks = gpmc_ns_to_clk_ticks(time, cs, cd);
nr_bits = end_bit - st_bit + 1;
mask = (1 << nr_bits) - 1;

if (ticks > mask) {
- pr_err("%s: GPMC error! CS%d: %s: %d ns, %d ticks > %d\n",
+ pr_err("%s: GPMC CS%d: %s %d ns, %d ticks > %d ticks\n",
__func__, cs, name, time, ticks, mask);

return -1;
@@ -498,7 +567,7 @@ static int set_gpmc_timing_reg(int cs, int reg, int st_bit, int end_bit,
#ifdef DEBUG
printk(KERN_INFO
"GPMC CS%d: %-17s: %3d ticks, %3lu ns (was %3i ticks) %3d ns\n",
- cs, name, ticks, gpmc_get_fclk_period() * ticks / 1000,
+ cs, name, ticks, gpmc_get_clk_period(cs, cd) * ticks / 1000,
(l >> st_bit) & mask, time);
#endif
l &= ~(mask << st_bit);
@@ -508,11 +577,14 @@ static int set_gpmc_timing_reg(int cs, int reg, int st_bit, int end_bit,
return 0;
}

-#define GPMC_SET_ONE(reg, st, end, field) \
- if (set_gpmc_timing_reg(cs, (reg), (st), (end), \
- t->field, #field) < 0) \
+#define GPMC_SET_ONE_CD(reg, st, end, field, cd) \
+ if (set_gpmc_timing_reg(cs, (reg), (st), (end), \
+ t->field, (cd), #field) < 0) \
return -1

+#define GPMC_SET_ONE(reg, st, end, field) \
+ GPMC_SET_ONE_CD(reg, st, end, field, GPMC_CD_FCLK)
+
/**
* gpmc_calc_waitmonitoring_divider - calculate proper GPMCFCLKDIVIDER based on WAITMONITORINGTIME
* @wait_monitoring WAITMONITORINGTIME in ns.
@@ -620,22 +692,23 @@ int gpmc_cs_set_timings(int cs, const struct gpmc_timings *t, const struct gpmc_
GPMC_SET_ONE(GPMC_CS_CONFIG6, 0, 3, bus_turnaround);
GPMC_SET_ONE(GPMC_CS_CONFIG6, 8, 11, cycle2cycle_delay);

- GPMC_SET_ONE(GPMC_CS_CONFIG1, 18, 19, wait_monitoring);
- GPMC_SET_ONE(GPMC_CS_CONFIG1, 25, 26, clk_activation);
-
if (gpmc_capability & GPMC_HAS_WR_DATA_MUX_BUS)
GPMC_SET_ONE(GPMC_CS_CONFIG6, 16, 19, wr_data_mux_bus);
if (gpmc_capability & GPMC_HAS_WR_ACCESS)
GPMC_SET_ONE(GPMC_CS_CONFIG6, 24, 28, wr_access);

l = gpmc_cs_read_reg(cs, GPMC_CS_CONFIG1);
+ l &= ~0x03;
+ l |= (div - 1);
+ gpmc_cs_write_reg(cs, GPMC_CS_CONFIG1, l);
+
+ GPMC_SET_ONE_CD(GPMC_CS_CONFIG1, 18, 19, wait_monitoring, GPMC_CD_CLK);
+ GPMC_SET_ONE(GPMC_CS_CONFIG1, 25, 26, clk_activation);
+
#ifdef DEBUG
printk(KERN_INFO "GPMC CS%d CLK period is %lu ns (div %d)\n",
cs, (div * gpmc_get_fclk_period()) / 1000, div);
#endif
- l &= ~0x03;
- l |= (div - 1);
- gpmc_cs_write_reg(cs, GPMC_CS_CONFIG1, l);

gpmc_cs_bool_timings(cs, &t->bool_timings);
gpmc_cs_show_timings(cs, "after gpmc_cs_set_timings");
--
2.3.0