Re: [PATCH v3 3/3] clk: qcom: Add Global Clock controller (GCC) driver for SDM845

From: Amit Nischal
Date: Wed Apr 18 2018 - 09:03:56 EST


On 2018-04-17 09:21, Stephen Boyd wrote:
Quoting Amit Nischal (2018-04-03 06:22:41)
diff --git a/drivers/clk/qcom/Kconfig b/drivers/clk/qcom/Kconfig
index fbf4532..c961e89 100644
--- a/drivers/clk/qcom/Kconfig
+++ b/drivers/clk/qcom/Kconfig
@@ -218,6 +218,15 @@ config MSM_MMCC_8996
Say Y if you want to support multimedia devices such as display,
graphics, video encode/decode, camera, etc.

+config SDM_GCC_845
+ tristate "SDM845 Global Clock Controller"
+ depends on COMMON_CLK_QCOM
+ help
+ Support for the global clock controller on Qualcomm Technologies, Inc
+ sdm845 devices.
+ Say Y if you want to use peripheral devices such as UART, SPI,
+ i2c, USB, UFS, SD/eMMC, PCIe, etc.

Is there eMMC?

Thanks for the review comments. There is no eMMC for SDM845. I will fix the
above in next patch series.


+
config SPMI_PMIC_CLKDIV
tristate "SPMI PMIC clkdiv Support"
depends on (COMMON_CLK_QCOM && SPMI) || COMPILE_TEST
diff --git a/drivers/clk/qcom/gcc-sdm845.c b/drivers/clk/qcom/gcc-sdm845.c
new file mode 100644
index 0000000..b1b7a1e
--- /dev/null
+++ b/drivers/clk/qcom/gcc-sdm845.c
@@ -0,0 +1,3546 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2018, The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/kernel.h>
+#include <linux/bitops.h>
+#include <linux/err.h>
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/clk.h>

Is this include used?

No, it is not getting used. We will remove this in next patch series.


+#include <linux/clk-provider.h>
+#include <linux/regmap.h>
+#include <linux/reset-controller.h>
+
[...]
+
+static struct clk_rcg2 gcc_usb30_prim_mock_utmi_clk_src = {
+ .cmd_rcgr = 0xf030,
+ .mnd_width = 0,
+ .hid_width = 5,
+ .parent_map = gcc_parent_map_0,
+ .freq_tbl = ftbl_gcc_usb30_prim_mock_utmi_clk_src,
+ .clkr.hw.init = &(struct clk_init_data){
+ .name = "gcc_usb30_prim_mock_utmi_clk_src",
+ .parent_names = gcc_parent_names_0,
+ .num_parents = 4,
+ .ops = &clk_rcg2_shared_ops,

Still shared? Why?

We would require the shared_ops for clocks which are configured by
bootloader.


+
+static struct clk_branch gcc_video_ahb_clk = {
+ .halt_reg = 0xb004,
+ .halt_check = BRANCH_HALT,
+ .hwcg_reg = 0xb004,
+ .hwcg_bit = 1,
+ .clkr = {
+ .enable_reg = 0xb004,
+ .enable_mask = BIT(0),
+ .hw.init = &(struct clk_init_data){
+ .name = "gcc_video_ahb_clk",
+ .flags = CLK_IS_CRITICAL,
+ .ops = &clk_branch2_ops,
+ },
+ },
+};
+
+

Weird double space here.

We will fix this in next patch series.


+static struct clk_branch gcc_video_xo_clk = {
+ .halt_reg = 0xb028,
+ .halt_check = BRANCH_HALT,
+ .clkr = {
+ .enable_reg = 0xb028,
+ .enable_mask = BIT(0),
+ .hw.init = &(struct clk_init_data){
+ .name = "gcc_video_xo_clk",
+ .flags = CLK_IS_CRITICAL,

For these "critical" clks that don't have parents can you just throw the
enable part in the gcc driver probe and remove these clks from being
exposed? They don't seem to provide any value to expose them as clks
when they don't hook into the final clk tree.


For all of the "critical" clocks which don't have parents, we have
removed the CRITICAL flag and mandate the clients to put their vote
to enable/disable them. Other than this, some of the "critical" clock
instances we have completely removed and enabled them in the probe.
This will be fixed in the next patch series.

+ .ops = &clk_branch2_ops,
+ },
+ },
+};
+
+static struct clk_branch gcc_vs_ctrl_ahb_clk = {
+ .halt_reg = 0x7a014,
+ .halt_check = BRANCH_HALT,
+ .hwcg_reg = 0x7a014,
+ .hwcg_bit = 1,
+ .clkr = {
+ .enable_reg = 0x7a014,
+ .enable_mask = BIT(0),
+ .hw.init = &(struct clk_init_data){
+ .name = "gcc_vs_ctrl_ahb_clk",
+ .ops = &clk_branch2_ops,
+ },
+ },
+};
+
+static struct clk_branch gcc_vs_ctrl_clk = {
+ .halt_reg = 0x7a010,
+ .halt_check = BRANCH_HALT,
+ .clkr = {
+ .enable_reg = 0x7a010,
+ .enable_mask = BIT(0),
+ .hw.init = &(struct clk_init_data){
+ .name = "gcc_vs_ctrl_clk",
+ .parent_names = (const char *[]){
+ "gcc_vs_ctrl_clk_src",
+ },
+ .num_parents = 1,
+ .flags = CLK_SET_RATE_PARENT,
+ .ops = &clk_branch2_ops,
+ },
+ },
+};
+
+
+static int gcc_sdm845_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct regmap *regmap;
+ int i, ret;
+
+ regmap = qcom_cc_map(pdev, &gcc_sdm845_desc);
+ if (IS_ERR(regmap))
+ return PTR_ERR(regmap);
+
+ for (i = 0; i < ARRAY_SIZE(gcc_sdm845_hws); i++) {
+ ret = devm_clk_hw_register(dev, gcc_sdm845_hws[i]);
+ if (ret)
+ return ret;
+ }
+
+ /* Disable the GPLL0 active input to MMSS and GPU via MISC registers */
+ regmap_update_bits(regmap, 0x09ffc, 0x3, 0x3);
+ regmap_update_bits(regmap, 0x71028, 0x3, 0x3);

I think we'll have to throw in the pipe clk branch stuff in here too?
And then drop the pipe clks from the driver?

All the USB pipe clocks would be taken care. The PCIE pipe branch
clocks would have to be explicitly disabled so as to retain the
memory logic. Otherwise, it would lead to memory corruption in case
the external source is directly disabled without disabling the branch clock.


+
+ return qcom_cc_really_probe(pdev, &gcc_sdm845_desc, regmap);
+}
+
diff --git a/include/dt-bindings/clock/qcom,gcc-sdm845.h b/include/dt-bindings/clock/qcom,gcc-sdm845.h
new file mode 100644
index 0000000..e27d8e2
--- /dev/null
+++ b/include/dt-bindings/clock/qcom,gcc-sdm845.h
@@ -0,0 +1,242 @@
[...]
+#define GCC_VDDA_VS_CLK 180
+#define GCC_VDDCX_VS_CLK 181
+#define GCC_VDDMX_VS_CLK 182
+#define GCC_VS_CTRL_AHB_CLK 183
+#define GCC_VS_CTRL_CLK 184
+#define GCC_VS_CTRL_CLK_SRC 185
+#define GCC_VSENSOR_CLK_SRC 186
+#define GPLL4 187

Do you have the define for the quad spi clks? And the implementation for
it?


In SDM845, Quad SPI clocks are part of gcc_qupv*_wrap*_s* clock group.

+
+/* GCC reset clocks */

They're just resets, not reset clks.

Will fix this in next patch series.


+#define GCC_MMSS_BCR 0
+#define GCC_PCIE_0_BCR 1
+#define GCC_PCIE_1_BCR 2
+#define GCC_PCIE_PHY_BCR 3
+#define GCC_PDM_BCR 4
+#define GCC_PRNG_BCR 5
+#define GCC_QUPV3_WRAPPER_0_BCR 6
+#define GCC_QUPV3_WRAPPER_1_BCR 7