+++ /dev/null
-From f8e7e4a65b3f99452db67cfb7e21afc80b8af7f2 Mon Sep 17 00:00:00 2001
-From: Phil Elwell <phil@raspberrypi.org>
-Date: Mon, 6 Mar 2017 09:06:18 +0000
-Subject: [PATCH] clk-bcm2835: Read max core clock from firmware
-
-The VPU is responsible for managing the core clock, usually under
-direction from the bcm2835-cpufreq driver but not via the clk-bcm2835
-driver. Since the core frequency can change without warning, it is
-safer to report the maximum clock rate to users of the core clock -
-I2C, SPI and the mini UART - to err on the safe side when calculating
-clock divisors.
-
-If the DT node for the clock driver includes a reference to the
-firmware node, use the firmware API to query the maximum core clock
-instead of reading the divider registers.
-
-Prior to this patch, a "100KHz" I2C bus was sometimes clocked at about
-160KHz. In particular, switching to the 4.9 kernel was likely to break
-SenseHAT usage on a Pi3.
-
-Signed-off-by: Phil Elwell <phil@raspberrypi.org>
----
- drivers/clk/bcm/clk-bcm2835.c | 39 ++++++++++++++++++++++++++++++++++-
- 1 file changed, 38 insertions(+), 1 deletion(-)
-
---- a/drivers/clk/bcm/clk-bcm2835.c
-+++ b/drivers/clk/bcm/clk-bcm2835.c
-@@ -44,6 +44,7 @@
- #include <linux/platform_device.h>
- #include <linux/slab.h>
- #include <dt-bindings/clock/bcm2835.h>
-+#include <soc/bcm2835/raspberrypi-firmware.h>
-
- #define CM_PASSWORD 0x5a000000
-
-@@ -298,6 +299,8 @@
- #define LOCK_TIMEOUT_NS 100000000
- #define BCM2835_MAX_FB_RATE 1750000000u
-
-+#define VCMSG_ID_CORE_CLOCK 4
-+
- /*
- * Names of clocks used within the driver that need to be replaced
- * with an external parent's name. This array is in the order that
-@@ -316,6 +319,7 @@ static const char *const cprman_parent_n
- struct bcm2835_cprman {
- struct device *dev;
- void __iomem *regs;
-+ struct rpi_firmware *fw;
- spinlock_t regs_lock; /* spinlock for all clocks */
-
- /*
-@@ -998,6 +1002,30 @@ static unsigned long bcm2835_clock_get_r
- return bcm2835_clock_rate_from_divisor(clock, parent_rate, div);
- }
-
-+static unsigned long bcm2835_clock_get_rate_vpu(struct clk_hw *hw,
-+ unsigned long parent_rate)
-+{
-+ struct bcm2835_clock *clock = bcm2835_clock_from_hw(hw);
-+ struct bcm2835_cprman *cprman = clock->cprman;
-+
-+ if (cprman->fw) {
-+ struct {
-+ u32 id;
-+ u32 val;
-+ } packet;
-+
-+ packet.id = VCMSG_ID_CORE_CLOCK;
-+ packet.val = 0;
-+
-+ if (!rpi_firmware_property(cprman->fw,
-+ RPI_FIRMWARE_GET_MAX_CLOCK_RATE,
-+ &packet, sizeof(packet)))
-+ return packet.val;
-+ }
-+
-+ return bcm2835_clock_get_rate(hw, parent_rate);
-+}
-+
- static void bcm2835_clock_wait_busy(struct bcm2835_clock *clock)
- {
- struct bcm2835_cprman *cprman = clock->cprman;
-@@ -1286,7 +1314,7 @@ static int bcm2835_vpu_clock_is_on(struc
- */
- static const struct clk_ops bcm2835_vpu_clock_clk_ops = {
- .is_prepared = bcm2835_vpu_clock_is_on,
-- .recalc_rate = bcm2835_clock_get_rate,
-+ .recalc_rate = bcm2835_clock_get_rate_vpu,
- .set_rate = bcm2835_clock_set_rate,
- .determine_rate = bcm2835_clock_determine_rate,
- .set_parent = bcm2835_clock_set_parent,
-@@ -2165,6 +2193,7 @@ static int bcm2835_clk_probe(struct plat
- struct resource *res;
- const struct bcm2835_clk_desc *desc;
- const size_t asize = ARRAY_SIZE(clk_desc_array);
-+ struct device_node *fw_node;
- size_t i;
- u32 clk_id;
- int ret;
-@@ -2182,6 +2211,14 @@ static int bcm2835_clk_probe(struct plat
- if (IS_ERR(cprman->regs))
- return PTR_ERR(cprman->regs);
-
-+ fw_node = of_parse_phandle(dev->of_node, "firmware", 0);
-+ if (fw_node) {
-+ struct rpi_firmware *fw = rpi_firmware_get(NULL);
-+ if (!fw)
-+ return -EPROBE_DEFER;
-+ cprman->fw = fw;
-+ }
-+
- memset(bcm2835_clk_claimed, 0, sizeof(bcm2835_clk_claimed));
- for (i = 0;
- !of_property_read_u32_index(pdev->dev.of_node, "claim-clocks",
projects / openwrt / staging / chunkeey.git / blobdiff