[Patch v3 09/11] PCI: tegra194: add interconnect support in Tegra234

From: Sumit Gupta
Date: Mon Mar 20 2023 - 14:36:35 EST


Add support to request DRAM bandwidth with Memory Interconnect
in Tegra234 SoC. The DRAM BW required for different modes depends
on speed (Gen-1/2/3/4) and width/lanes (x1/x2/x4/x8).

Suggested-by: Manikanta Maddireddy <mmaddireddy@xxxxxxxxxx>
Signed-off-by: Sumit Gupta <sumitg@xxxxxxxxxx>
---
drivers/pci/controller/dwc/pcie-tegra194.c | 40 +++++++++++++++++-----
1 file changed, 32 insertions(+), 8 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
index 09825b4a075e..d2513c9d3feb 100644
--- a/drivers/pci/controller/dwc/pcie-tegra194.c
+++ b/drivers/pci/controller/dwc/pcie-tegra194.c
@@ -15,6 +15,7 @@
#include <linux/gpio.h>
#include <linux/gpio/consumer.h>
#include <linux/interrupt.h>
+#include <linux/interconnect.h>
#include <linux/iopoll.h>
#include <linux/kernel.h>
#include <linux/module.h>
@@ -287,6 +288,7 @@ struct tegra_pcie_dw {
unsigned int pex_rst_irq;
int ep_state;
long link_status;
+ struct icc_path *icc_path;
};

static inline struct tegra_pcie_dw *to_tegra_pcie(struct dw_pcie *pci)
@@ -309,6 +311,24 @@ struct tegra_pcie_soc {
enum dw_pcie_device_mode mode;
};

+static void tegra_pcie_icc_set(struct tegra_pcie_dw *pcie)
+{
+ struct dw_pcie *pci = &pcie->pci;
+ u32 val, speed, width;
+
+ val = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA);
+
+ speed = FIELD_GET(PCI_EXP_LNKSTA_CLS, val);
+ width = FIELD_GET(PCI_EXP_LNKSTA_NLW, val);
+
+ val = width * (PCIE_SPEED2MBS_ENC(pcie_link_speed[speed]) / BITS_PER_BYTE);
+
+ if (icc_set_bw(pcie->icc_path, MBps_to_icc(val), 0))
+ dev_err(pcie->dev, "can't set bw[%u]\n", val);
+
+ clk_set_rate(pcie->core_clk, pcie_gen_freq[speed - 1]);
+}
+
static void apply_bad_link_workaround(struct dw_pcie_rp *pp)
{
struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
@@ -452,14 +472,12 @@ static irqreturn_t tegra_pcie_ep_irq_thread(int irq, void *arg)
struct tegra_pcie_dw *pcie = arg;
struct dw_pcie_ep *ep = &pcie->pci.ep;
struct dw_pcie *pci = &pcie->pci;
- u32 val, speed;
+ u32 val;

if (test_and_clear_bit(0, &pcie->link_status))
dw_pcie_ep_linkup(ep);

- speed = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA) &
- PCI_EXP_LNKSTA_CLS;
- clk_set_rate(pcie->core_clk, pcie_gen_freq[speed - 1]);
+ tegra_pcie_icc_set(pcie);

if (pcie->of_data->has_ltr_req_fix)
return IRQ_HANDLED;
@@ -945,9 +963,9 @@ static int tegra_pcie_dw_host_init(struct dw_pcie_rp *pp)

static int tegra_pcie_dw_start_link(struct dw_pcie *pci)
{
- u32 val, offset, speed, tmp;
struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
struct dw_pcie_rp *pp = &pci->pp;
+ u32 val, offset, tmp;
bool retry = true;

if (pcie->of_data->mode == DW_PCIE_EP_TYPE) {
@@ -1018,9 +1036,7 @@ static int tegra_pcie_dw_start_link(struct dw_pcie *pci)
goto retry_link;
}

- speed = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA) &
- PCI_EXP_LNKSTA_CLS;
- clk_set_rate(pcie->core_clk, pcie_gen_freq[speed - 1]);
+ tegra_pcie_icc_set(pcie);

tegra_pcie_enable_interrupts(pp);

@@ -2224,6 +2240,14 @@ static int tegra_pcie_dw_probe(struct platform_device *pdev)

platform_set_drvdata(pdev, pcie);

+ pcie->icc_path = devm_of_icc_get(&pdev->dev, "write");
+ ret = PTR_ERR_OR_ZERO(pcie->icc_path);
+ if (ret) {
+ tegra_bpmp_put(pcie->bpmp);
+ dev_err_probe(&pdev->dev, ret, "failed to get write interconnect\n");
+ return ret;
+ }
+
switch (pcie->of_data->mode) {
case DW_PCIE_RC_TYPE:
ret = devm_request_irq(dev, pp->irq, tegra_pcie_rp_irq_handler,
--
2.17.1