On Wed, Aug 12, 2020 at 02:34:34PM +0200, Mateusz Holenko wrote:
From: Pawel Czarnecki <redacted>
This commit adds driver for the FPGA-based LiteX SoC
Controller from LiteX SoC builder.
Co-developed-by: Mateusz Holenko <mholenko@antmicro.com>
Signed-off-by: Mateusz Holenko <mholenko@antmicro.com>
Signed-off-by: Pawel Czarnecki <redacted>
---
...
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+static int litex_check_csr_access(void __iomem *reg_addr)
+{
+ unsigned long reg;
+
+ reg = litex_get_reg(reg_addr + SCRATCH_REG_OFF, SCRATCH_REG_SIZE);
+
+ if (reg != SCRATCH_REG_VALUE) {
+ panic("Scratch register read error! Expected: 0x%x but got: 0x%lx",
+ SCRATCH_REG_VALUE, reg);
+ return -EINVAL;
+ }
+
+ litex_set_reg(reg_addr + SCRATCH_REG_OFF,
+ SCRATCH_REG_SIZE, SCRATCH_TEST_VALUE);
+ reg = litex_get_reg(reg_addr + SCRATCH_REG_OFF, SCRATCH_REG_SIZE);
+
+ if (reg != SCRATCH_TEST_VALUE) {
+ panic("Scratch register write error! Expected: 0x%x but got: 0x%lx",
+ SCRATCH_TEST_VALUE, reg);
+ return -EINVAL;
+ }
+
+ /* restore original value of the SCRATCH register */
+ litex_set_reg(reg_addr + SCRATCH_REG_OFF,
+ SCRATCH_REG_SIZE, SCRATCH_REG_VALUE);
+
+ /* Set flag for other drivers */
What does this comment mean?
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+ pr_info("LiteX SoC Controller driver initialized");
+
+ return 0;
+}
+
+struct litex_soc_ctrl_device {
+ void __iomem *base;
+};
+
+static const struct of_device_id litex_soc_ctrl_of_match[] = {
+ {.compatible = "litex,soc-controller"},
+ {},
+};
+
+MODULE_DEVICE_TABLE(of, litex_soc_ctrl_of_match);
+
+static int litex_soc_ctrl_probe(struct platform_device *pdev)
+{
+ int result;
+ struct device *dev;
+ struct device_node *node;
+ struct litex_soc_ctrl_device *soc_ctrl_dev;
+
+ dev = &pdev->dev;
+ node = dev->of_node;
+ if (!node)
+ return -ENODEV;
+
+ soc_ctrl_dev = devm_kzalloc(dev, sizeof(*soc_ctrl_dev), GFP_KERNEL);
+ if (!soc_ctrl_dev)
+ return -ENOMEM;
+
+ soc_ctrl_dev->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(soc_ctrl_dev->base))
+ return PTR_ERR(soc_ctrl_dev->base);
+
+ result = litex_check_csr_access(soc_ctrl_dev->base);
+ if (result) {
+ // LiteX CSRs access is broken which means that
+ // none of LiteX drivers will most probably
+ // operate correctly
The comment format here with // is not usually used in the kernel, but its not
forbidded. Could you use the /* */ multiline style?
+ BUG();
Instead of stopping the system with BUG, could we just do:
return litex_check_csr_access(soc_ctrl_dev->base);
We already have failure for NODEV/NOMEM so might as well not call BUG() here
too.
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Other than that it looks ok to me.
-Stafford