Added functionality to modify clock frequency via DTS entry.
Signed-off-by: Damian Eppel <[email protected]>
Signed-off-by: Piyush Malgujar <[email protected]>
---
drivers/net/mdio/mdio-cavium.h | 1 +
drivers/net/mdio/mdio-thunder.c | 63 +++++++++++++++++++++++++++++++++
2 files changed, 64 insertions(+)
diff --git a/drivers/net/mdio/mdio-cavium.h b/drivers/net/mdio/mdio-cavium.h
index a2245d436f5dae4d6424b7c7bfca0aa969a3b3ad..ed4c48d8a38bd80e6a169f7a6d90c1f2a0daccfc 100644
--- a/drivers/net/mdio/mdio-cavium.h
+++ b/drivers/net/mdio/mdio-cavium.h
@@ -92,6 +92,7 @@ struct cavium_mdiobus {
struct mii_bus *mii_bus;
void __iomem *register_base;
enum cavium_mdiobus_mode mode;
+ u32 clk_freq;
};
#ifdef CONFIG_CAVIUM_OCTEON_SOC
diff --git a/drivers/net/mdio/mdio-thunder.c b/drivers/net/mdio/mdio-thunder.c
index 715c835ace785da345ac037177b0f291678e4c47..7ea6ef0a23f3f5d7df76e3a7aed007ed847f9140 100644
--- a/drivers/net/mdio/mdio-thunder.c
+++ b/drivers/net/mdio/mdio-thunder.c
@@ -14,11 +14,56 @@
#include "mdio-cavium.h"
+#define PHASE_MIN 3
+#define PHASE_DFLT 16
+
struct thunder_mdiobus_nexus {
void __iomem *bar0;
struct cavium_mdiobus *buses[4];
};
+static inline u32 clk_freq(u32 phase)
+{
+ return (100000000U / (2 * (phase)));
+}
+
+static inline u32 calc_sample(u32 phase)
+{
+ return (2 * (phase) - 3);
+}
+
+static u32 _config_clk(u32 req_freq, u32 *phase, u32 *sample)
+{
+ unsigned int p;
+ u32 freq = 0, freq_prev;
+
+ for (p = PHASE_MIN; p < PHASE_DFLT; p++) {
+ freq_prev = freq;
+ freq = clk_freq(p);
+
+ if (req_freq >= freq)
+ break;
+ }
+
+ if (p == PHASE_DFLT)
+ freq = clk_freq(PHASE_DFLT);
+
+ if (p == PHASE_MIN || p == PHASE_DFLT)
+ goto out;
+
+ /* Check which clock value from the identified range
+ * is closer to the requested value
+ */
+ if ((freq_prev - req_freq) < (req_freq - freq)) {
+ p = p - 1;
+ freq = freq_prev;
+ }
+out:
+ *phase = p;
+ *sample = calc_sample(p);
+ return freq;
+}
+
static int thunder_mdiobus_pci_probe(struct pci_dev *pdev,
const struct pci_device_id *ent)
{
@@ -56,6 +101,7 @@ static int thunder_mdiobus_pci_probe(struct pci_dev *pdev,
i = 0;
device_for_each_child_node(&pdev->dev, fwn) {
struct resource r;
+ u32 req_clk_freq;
struct mii_bus *mii_bus;
struct cavium_mdiobus *bus;
union cvmx_smix_clk smi_clk;
@@ -90,6 +136,23 @@ static int thunder_mdiobus_pci_probe(struct pci_dev *pdev,
smi_clk.u64 = oct_mdio_readq(bus->register_base + SMI_CLK);
smi_clk.s.clk_idle = 1;
+
+ if (!of_property_read_u32(node, "clock-frequency", &req_clk_freq)) {
+ u32 phase, sample;
+
+ dev_dbg(&pdev->dev, "requested bus clock frequency=%d\n",
+ req_clk_freq);
+
+ bus->clk_freq = _config_clk(req_clk_freq,
+ &phase, &sample);
+
+ smi_clk.s.phase = phase;
+ smi_clk.s.sample_hi = (sample >> 4) & 0x1f;
+ smi_clk.s.sample = sample & 0xf;
+ } else {
+ bus->clk_freq = clk_freq(PHASE_DFLT);
+ }
+
oct_mdio_writeq(smi_clk.u64, bus->register_base + SMI_CLK);
smi_en.u64 = 0;
--
2.17.1
On Mon, 30 May 2022 05:53:28 -0700 Piyush Malgujar wrote:
> +static inline u32 clk_freq(u32 phase)
> +{
> + return (100000000U / (2 * (phase)));
> +}
> +
> +static inline u32 calc_sample(u32 phase)
Please drop the inline keyword, the compiler will inline this anyway
and static inline prevents unused code warnings.
> +{
> + return (2 * (phase) - 3);
No need to wrap arguments to a static inline in brackets.
> +}
> +
> +static u32 _config_clk(u32 req_freq, u32 *phase, u32 *sample)
> +{
> + unsigned int p;
> + u32 freq = 0, freq_prev;
It's customary in networking to order variable decl lines longest
to shortest.
> + for (p = PHASE_MIN; p < PHASE_DFLT; p++) {
> + freq_prev = freq;
> + freq = clk_freq(p);
> +
> + if (req_freq >= freq)
> + break;
> + }
> +
> + if (p == PHASE_DFLT)
> + freq = clk_freq(PHASE_DFLT);
> +
> + if (p == PHASE_MIN || p == PHASE_DFLT)
> + goto out;
> +
> + /* Check which clock value from the identified range
> + * is closer to the requested value
> + */
> + if ((freq_prev - req_freq) < (req_freq - freq)) {
No need for brackets around the arithmetic, assume basic operator
precedence is not broken in the compiler...
> +static inline u32 clk_freq(u32 phase)
Please keep with the naming scheme in the rest of the driver,
thunder_mdiobus_clk_freq()
> +{
> + return (100000000U / (2 * (phase)));
> +}
> +
> +static inline u32 calc_sample(u32 phase)
> +{
thunder_mdiobus_calc_sample()
> + return (2 * (phase) - 3);
> +}
> +
> +static u32 _config_clk(u32 req_freq, u32 *phase, u32 *sample)
thunder_mdiobus_config_clk().
> +{
> + unsigned int p;
> + u32 freq = 0, freq_prev;
> +
> + for (p = PHASE_MIN; p < PHASE_DFLT; p++) {
> + freq_prev = freq;
> + freq = clk_freq(p);
> +
> + if (req_freq >= freq)
> + break;
> + }
> +
> + if (p == PHASE_DFLT)
> + freq = clk_freq(PHASE_DFLT);
> +
> + if (p == PHASE_MIN || p == PHASE_DFLT)
> + goto out;
> +
> + /* Check which clock value from the identified range
> + * is closer to the requested value
> + */
> + if ((freq_prev - req_freq) < (req_freq - freq)) {
> + p = p - 1;
> + freq = freq_prev;
> + }
> +out:
> + *phase = p;
> + *sample = calc_sample(p);
> + return freq;
> +}
> +
> static int thunder_mdiobus_pci_probe(struct pci_dev *pdev,
> const struct pci_device_id *ent)
> {
> @@ -56,6 +101,7 @@ static int thunder_mdiobus_pci_probe(struct pci_dev *pdev,
> i = 0;
> device_for_each_child_node(&pdev->dev, fwn) {
> struct resource r;
> + u32 req_clk_freq;
> struct mii_bus *mii_bus;
> struct cavium_mdiobus *bus;
> union cvmx_smix_clk smi_clk;
> @@ -90,6 +136,23 @@ static int thunder_mdiobus_pci_probe(struct pci_dev *pdev,
>
> smi_clk.u64 = oct_mdio_readq(bus->register_base + SMI_CLK);
> smi_clk.s.clk_idle = 1;
> +
> + if (!of_property_read_u32(node, "clock-frequency", &req_clk_freq)) {
> + u32 phase, sample;
> +
> + dev_dbg(&pdev->dev, "requested bus clock frequency=%d\n",
> + req_clk_freq);
> +
> + bus->clk_freq = _config_clk(req_clk_freq,
> + &phase, &sample);
> +
> + smi_clk.s.phase = phase;
> + smi_clk.s.sample_hi = (sample >> 4) & 0x1f;
> + smi_clk.s.sample = sample & 0xf;
> + } else {
> + bus->clk_freq = clk_freq(PHASE_DFLT);
> + }
You can make this simpler by setting req_clk_freq to your odd
default. Then call of_property_read_u32(). If the property is not
defined, the value of req_clk_freq will not be changed, and the
calculation should come out with the correct value.
Andrew